diff --git a/.travis.yml b/.travis.yml
index 84e6fff8d..1da5be0e9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,7 +10,7 @@ env:
     - SYMFONY_DEPRECATIONS_HELPER="max[self]=0"
     - PHPUNIT_FLAGS="-v"
     - PHPUNIT_ENABLED="true"
-    - SYMFONY_PHPUNIT_VERSION="6.5"
+    - SYMFONY_PHPUNIT_VERSION="7.5"
     - COVERALLS_ENABLED="false"
     - STABILITY=stable
 
diff --git a/Tests/AbstractTest.php b/Tests/AbstractTest.php
index c017ef21c..8a082c475 100644
--- a/Tests/AbstractTest.php
+++ b/Tests/AbstractTest.php
@@ -25,6 +25,7 @@
 use Liip\ImagineBundle\Imagine\Filter\FilterManager;
 use Liip\ImagineBundle\Imagine\Filter\PostProcessor\PostProcessorInterface;
 use Liip\ImagineBundle\Service\FilterService;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
@@ -77,7 +78,7 @@ protected function tearDown()
     /**
      * @return string[]
      */
-    public function invalidPathProvider()
+    public function invalidPathProvider(): array
     {
         return [
             [$this->fixturesPath.'/assets/../../foobar.png'],
@@ -86,10 +87,7 @@ public function invalidPathProvider()
         ];
     }
 
-    /**
-     * @return FilterConfiguration
-     */
-    protected function createFilterConfiguration()
+    protected function createFilterConfiguration(): FilterConfiguration
     {
         $config = new FilterConfiguration();
         $config->set('thumbnail', [
@@ -101,7 +99,7 @@ protected function createFilterConfiguration()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|CacheManager
+     * @return MockObject|CacheManager
      */
     protected function createCacheManagerMock()
     {
@@ -117,7 +115,7 @@ protected function createCacheManagerMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|FilterConfiguration
+     * @return MockObject|FilterConfiguration
      */
     protected function createFilterConfigurationMock()
     {
@@ -125,7 +123,7 @@ protected function createFilterConfigurationMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|SignerInterface
+     * @return MockObject|SignerInterface
      */
     protected function createSignerInterfaceMock()
     {
@@ -133,7 +131,7 @@ protected function createSignerInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|RouterInterface
+     * @return MockObject|RouterInterface
      */
     protected function createRouterInterfaceMock()
     {
@@ -141,7 +139,7 @@ protected function createRouterInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ResolverInterface
+     * @return MockObject|ResolverInterface
      */
     protected function createCacheResolverInterfaceMock()
     {
@@ -149,7 +147,7 @@ protected function createCacheResolverInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|EventDispatcherInterface
+     * @return MockObject|EventDispatcherInterface
      */
     protected function createEventDispatcherInterfaceMock()
     {
@@ -157,7 +155,7 @@ protected function createEventDispatcherInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ImageInterface
+     * @return MockObject|ImageInterface
      */
     protected function getImageInterfaceMock()
     {
@@ -165,7 +163,7 @@ protected function getImageInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|MetadataBag
+     * @return MockObject|MetadataBag
      */
     protected function getMetadataBagMock()
     {
@@ -173,7 +171,7 @@ protected function getMetadataBagMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ImagineInterface
+     * @return MockObject|ImagineInterface
      */
     protected function createImagineInterfaceMock()
     {
@@ -181,7 +179,7 @@ protected function createImagineInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|LoggerInterface
+     * @return MockObject|LoggerInterface
      */
     protected function createLoggerInterfaceMock()
     {
@@ -189,7 +187,7 @@ protected function createLoggerInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|LoaderInterface
+     * @return MockObject|LoaderInterface
      */
     protected function createBinaryLoaderInterfaceMock()
     {
@@ -197,7 +195,7 @@ protected function createBinaryLoaderInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|MimeTypeGuesserInterface
+     * @return MockObject|MimeTypeGuesserInterface
      */
     protected function createMimeTypeGuesserInterfaceMock()
     {
@@ -205,7 +203,7 @@ protected function createMimeTypeGuesserInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ExtensionGuesserInterface
+     * @return MockObject|ExtensionGuesserInterface
      */
     protected function createExtensionGuesserInterfaceMock()
     {
@@ -217,7 +215,7 @@ protected function createExtensionGuesserInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|PostProcessorInterface
+     * @return MockObject|PostProcessorInterface
      */
     protected function createPostProcessorInterfaceMock()
     {
@@ -225,7 +223,7 @@ protected function createPostProcessorInterfaceMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|FilterManager
+     * @return MockObject|FilterManager
      */
     protected function createFilterManagerMock()
     {
@@ -233,15 +231,15 @@ protected function createFilterManagerMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|FilterService
+     * @return MockObject|FilterService
      */
     protected function createFilterServiceMock()
     {
-        return $this->createObjectMock('\Liip\ImagineBundle\Service\FilterService');
+        return $this->createObjectMock(FilterService::class);
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|DataManager
+     * @return MockObject|DataManager
      */
     protected function createDataManagerMock()
     {
@@ -254,14 +252,10 @@ protected function createControllerConfigInstance(int $redirectResponseCode = nu
     }
 
     /**
-     * @param string   $object
      * @param string[] $methods
-     * @param bool     $constructorInvoke
      * @param mixed[]  $constructorParams
-     *
-     * @return \PHPUnit_Framework_MockObject_MockObject
      */
-    protected function createObjectMock($object, array $methods = [], $constructorInvoke = false, array $constructorParams = [])
+    protected function createObjectMock(string $object, array $methods = [], bool $constructorInvoke = false, array $constructorParams = []): MockObject
     {
         $builder = $this->getMockBuilder($object);
 
@@ -284,11 +278,8 @@ protected function createObjectMock($object, array $methods = [], $constructorIn
 
     /**
      * @param object $object
-     * @param string $name
-     *
-     * @return \ReflectionMethod
      */
-    protected function getVisibilityRestrictedMethod($object, $name)
+    protected function getVisibilityRestrictedMethod($object, string $name): \ReflectionMethod
     {
         $r = new \ReflectionObject($object);
 
diff --git a/Tests/Async/CacheResolvedTest.php b/Tests/Async/CacheResolvedTest.php
index 7c79b029b..fbd6ef4fa 100644
--- a/Tests/Async/CacheResolvedTest.php
+++ b/Tests/Async/CacheResolvedTest.php
@@ -27,7 +27,7 @@ public static function setUpBeforeClass()
         }
     }
 
-    public function testCouldBeJsonSerialized()
+    public function testCouldBeJsonSerialized(): void
     {
         $message = new CacheResolved('thePath', [
             'fooFilter' => 'http://example.com/fooFilter/thePath',
@@ -40,11 +40,10 @@ public function testCouldBeJsonSerialized()
         );
     }
 
-    public function testCouldBeJsonDeSerialized()
+    public function testCouldBeJsonDeSerialized(): void
     {
         $message = CacheResolved::jsonDeserialize('{"path":"thePath","uris":{"fooFilter":"http:\/\/example.com\/fooFilter\/thePath","barFilter":"http:\/\/example.com\/barFilter\/thePath"}}');
 
-        $this->assertInstanceOf('Liip\ImagineBundle\Async\CacheResolved', $message);
         $this->assertSame('thePath', $message->getPath());
         $this->assertSame([
             'fooFilter' => 'http://example.com/fooFilter/thePath',
diff --git a/Tests/Async/ResolveCacheProcessorTest.php b/Tests/Async/ResolveCacheProcessorTest.php
index 7ebc8b9a4..6c26a86d3 100644
--- a/Tests/Async/ResolveCacheProcessorTest.php
+++ b/Tests/Async/ResolveCacheProcessorTest.php
@@ -28,6 +28,7 @@
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Service\FilterService;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\Async\ResolveCacheProcessor
@@ -41,32 +42,32 @@ public static function setUpBeforeClass()
         }
     }
 
-    public function testShouldImplementProcessorInterface()
+    public function testShouldImplementProcessorInterface(): void
     {
         $rc = new \ReflectionClass(ResolveCacheProcessor::class);
 
         $this->assertTrue($rc->implementsInterface(Processor::class));
     }
 
-    public function testShouldImplementCommandSubscriberInterface()
+    public function testShouldImplementCommandSubscriberInterface(): void
     {
         $rc = new \ReflectionClass(ResolveCacheProcessor::class);
 
         $this->assertTrue($rc->implementsInterface(CommandSubscriberInterface::class));
     }
 
-    public function testShouldImplementQueueSubscriberInterface()
+    public function testShouldImplementQueueSubscriberInterface(): void
     {
         $rc = new \ReflectionClass(ResolveCacheProcessor::class);
 
         $this->assertTrue($rc->implementsInterface(QueueSubscriberInterface::class));
     }
 
-    public function testShouldSubscribeToExpectedCommand()
+    public function testShouldSubscribeToExpectedCommand(): void
     {
         $command = ResolveCacheProcessor::getSubscribedCommand();
 
-        $this->assertInternalType('array', $command);
+        $this->assertIsArray($command);
         $this->assertSame([
             'command' => Commands::RESOLVE_CACHE,
             'queue' => Commands::RESOLVE_CACHE,
@@ -75,15 +76,15 @@ public function testShouldSubscribeToExpectedCommand()
         ], $command);
     }
 
-    public function testShouldSubscribeToExpectedQueue()
+    public function testShouldSubscribeToExpectedQueue(): void
     {
         $queues = ResolveCacheProcessor::getSubscribedQueues();
 
-        $this->assertInternalType('array', $queues);
+        $this->assertIsArray($queues);
         $this->assertSame(['liip_imagine_resolve_cache'], $queues);
     }
 
-    public function testCouldBeConstructedWithExpectedArguments()
+    public function testCouldBeConstructedWithExpectedArguments(): void
     {
         $processor = new ResolveCacheProcessor(
             $this->createFilterManagerMock(),
@@ -94,7 +95,7 @@ public function testCouldBeConstructedWithExpectedArguments()
         $this->assertInstanceOf(ResolveCacheProcessor::class, $processor);
     }
 
-    public function testShouldRejectMessagesWithInvalidJsonBody()
+    public function testShouldRejectMessagesWithInvalidJsonBody(): void
     {
         $processor = new ResolveCacheProcessor(
             $this->createFilterManagerMock(),
@@ -107,12 +108,12 @@ public function testShouldRejectMessagesWithInvalidJsonBody()
 
         $result = $processor->process($message, new NullContext());
 
-        $this->assertInstanceOf('Enqueue\Consumption\Result', $result);
+        $this->assertInstanceOf(Result::class, $result);
         $this->assertSame(Result::REJECT, $result->getStatus());
         $this->assertStringStartsWith('The malformed json given.', $result->getReason());
     }
 
-    public function testShouldSendFailedReplyOnException()
+    public function testShouldSendFailedReplyOnException(): void
     {
         $processor = new ResolveCacheProcessor(
             $this->createFilterManagerMock(),
@@ -136,7 +137,7 @@ public function testShouldSendFailedReplyOnException()
         );
     }
 
-    public function testShouldRejectMessagesWithoutPass()
+    public function testShouldRejectMessagesWithoutPass(): void
     {
         $processor = new ResolveCacheProcessor(
             $this->createFilterManagerMock(),
@@ -149,12 +150,12 @@ public function testShouldRejectMessagesWithoutPass()
 
         $result = $processor->process($message, new NullContext());
 
-        $this->assertInstanceOf('Enqueue\Consumption\Result', $result);
+        $this->assertInstanceOf(Result::class, $result);
         $this->assertSame(Result::REJECT, (string) $result);
         $this->assertSame('The message does not contain "path" but it is required.', $result->getReason());
     }
 
-    public function testShouldCreateFilteredImage()
+    public function testShouldCreateFilteredImage(): void
     {
         $filterName = 'fooFilter';
         $imagePath = 'theImagePath';
@@ -187,7 +188,7 @@ public function testShouldCreateFilteredImage()
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldCreateOneImagePerFilter()
+    public function testShouldCreateOneImagePerFilter(): void
     {
         $filterName1 = 'fooFilter';
         $filterName2 = 'barFilter';
@@ -225,7 +226,7 @@ public function testShouldCreateOneImagePerFilter()
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldOnlyCreateImageForRequestedFilter()
+    public function testShouldOnlyCreateImageForRequestedFilter(): void
     {
         $relevantFilter = 'fooFilter';
         $imagePath = 'theImagePath';
@@ -255,7 +256,7 @@ public function testShouldOnlyCreateImageForRequestedFilter()
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldCreateOneImagePerRequestedFilter()
+    public function testShouldCreateOneImagePerRequestedFilter(): void
     {
         $relevantFilter1 = 'fooFilter';
         $relevantFilter2 = 'fooFilter';
@@ -289,7 +290,7 @@ public function testShouldCreateOneImagePerRequestedFilter()
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldBurstCacheWhenResolvingForced()
+    public function testShouldBurstCacheWhenResolvingForced(): void
     {
         $filterName = 'fooFilter';
         $imagePath = 'theImagePath';
@@ -319,11 +320,11 @@ public function testShouldBurstCacheWhenResolvingForced()
 
         $result = $processor->process($message, new NullContext());
 
-        $this->assertInstanceOf('Enqueue\Consumption\Result', $result);
+        $this->assertInstanceOf(Result::class, $result);
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldNotBurstCacheWhenResolvingNotForced()
+    public function testShouldNotBurstCacheWhenResolvingNotForced(): void
     {
         $filterManagerMock = $this->createFilterManagerMock();
         $filterManagerMock
@@ -349,11 +350,11 @@ public function testShouldNotBurstCacheWhenResolvingNotForced()
 
         $result = $processor->process($message, new NullContext());
 
-        $this->assertInstanceOf('Enqueue\Consumption\Result', $result);
+        $this->assertInstanceOf(Result::class, $result);
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldSendMessageOnSuccessResolve()
+    public function testShouldSendMessageOnSuccessResolve(): void
     {
         $filterManagerMock = $this->createFilterManagerMock();
         $filterManagerMock
@@ -377,7 +378,7 @@ public function testShouldSendMessageOnSuccessResolve()
         $producerMock
             ->expects($this->once())
             ->method('sendEvent')
-            ->with(Topics::CACHE_RESOLVED, $this->isInstanceOf('Liip\ImagineBundle\Async\CacheResolved'))
+            ->with(Topics::CACHE_RESOLVED, $this->isInstanceOf(CacheResolved::class))
         ->willReturnCallback(function ($topic, CacheResolved $message) {
             $this->assertSame('theImagePath', $message->getPath());
             $this->assertSame([
@@ -398,11 +399,11 @@ public function testShouldSendMessageOnSuccessResolve()
 
         $result = $processor->process($message, new NullContext());
 
-        $this->assertInstanceOf('Enqueue\Consumption\Result', $result);
+        $this->assertInstanceOf(Result::class, $result);
         $this->assertSame(Result::ACK, (string) $result);
     }
 
-    public function testShouldReturnReplyOnSuccessResolve()
+    public function testShouldReturnReplyOnSuccessResolve(): void
     {
         $filterManagerMock = $this->createFilterManagerMock();
         $filterManagerMock
@@ -472,17 +473,14 @@ public function testShouldReturnReplyOnSuccessResolve()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ProducerInterface
+     * @return MockObject|ProducerInterface
      */
     private function createProducerMock()
     {
         return $this->createMock(ProducerInterface::class);
     }
 
-    /**
-     * @return Binary
-     */
-    private function createDummyBinary()
+    private function createDummyBinary(): Binary
     {
         return new Binary('theContent', 'image/png', 'png');
     }
diff --git a/Tests/Async/ResolveCacheTest.php b/Tests/Async/ResolveCacheTest.php
index e93456586..19aeffb77 100644
--- a/Tests/Async/ResolveCacheTest.php
+++ b/Tests/Async/ResolveCacheTest.php
@@ -27,68 +27,64 @@ public static function setUpBeforeClass()
         }
     }
 
-    public function testCouldBeJsonSerializedWithoutFiltersAndForce()
+    public function testCouldBeJsonSerializedWithoutFiltersAndForce(): void
     {
         $message = new ResolveCache('thePath');
 
         $this->assertSame('{"path":"thePath","filters":null,"force":false}', json_encode($message));
     }
 
-    public function testCouldBeJsonSerializedWithFilters()
+    public function testCouldBeJsonSerializedWithFilters(): void
     {
         $message = new ResolveCache('thePath', ['fooFilter', 'barFilter']);
 
         $this->assertSame('{"path":"thePath","filters":["fooFilter","barFilter"],"force":false}', json_encode($message));
     }
 
-    public function testCouldBeJsonSerializedWithFiltersAndForce()
+    public function testCouldBeJsonSerializedWithFiltersAndForce(): void
     {
         $message = new ResolveCache('thePath', ['fooFilter', 'barFilter'], true);
 
         $this->assertSame('{"path":"thePath","filters":["fooFilter","barFilter"],"force":true}', json_encode($message));
     }
 
-    public function testCouldBeJsonDeSerializedWithoutFiltersAndForce()
+    public function testCouldBeJsonDeSerializedWithoutFiltersAndForce(): void
     {
         $message = ResolveCache::jsonDeserialize('{"path":"thePath","filters":null,"force":false}');
 
-        $this->assertInstanceOf('Liip\ImagineBundle\Async\ResolveCache', $message);
         $this->assertSame('thePath', $message->getPath());
         $this->assertNull($message->getFilters());
         $this->assertFalse($message->isForce());
     }
 
-    public function testCouldBeJsonDeSerializedWithFilters()
+    public function testCouldBeJsonDeSerializedWithFilters(): void
     {
         $message = ResolveCache::jsonDeserialize('{"path":"thePath","filters":["fooFilter","barFilter"],"force":false}');
 
-        $this->assertInstanceOf('Liip\ImagineBundle\Async\ResolveCache', $message);
         $this->assertSame('thePath', $message->getPath());
         $this->assertSame(['fooFilter', 'barFilter'], $message->getFilters());
         $this->assertFalse($message->isForce());
     }
 
-    public function testCouldBeJsonDeSerializedWithFiltersAndForce()
+    public function testCouldBeJsonDeSerializedWithFiltersAndForce(): void
     {
         $message = ResolveCache::jsonDeserialize('{"path":"thePath","filters":["fooFilter","barFilter"],"force":true}');
 
-        $this->assertInstanceOf('Liip\ImagineBundle\Async\ResolveCache', $message);
         $this->assertSame('thePath', $message->getPath());
         $this->assertSame(['fooFilter', 'barFilter'], $message->getFilters());
         $this->assertTrue($message->isForce());
     }
 
-    public function testCouldBeJsonDeSerializedWithOnlyPath()
+    public function testCouldBeJsonDeSerializedWithOnlyPath(): void
     {
         $message = ResolveCache::jsonDeserialize('{"path":"thePath"}');
 
-        $this->assertInstanceOf('Liip\ImagineBundle\Async\ResolveCache', $message);
         $this->assertSame('thePath', $message->getPath());
         $this->assertNull($message->getFilters());
         $this->assertFalse($message->isForce());
     }
 
-    public function testThrowIfMessageMissingPathOnJsonDeserialize()
+    public function testThrowIfMessageMissingPathOnJsonDeserialize(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\LogicException::class);
         $this->expectExceptionMessage('The message does not contain "path" but it is required.');
@@ -96,7 +92,7 @@ public function testThrowIfMessageMissingPathOnJsonDeserialize()
         ResolveCache::jsonDeserialize('{}');
     }
 
-    public function testThrowIfMessageContainsNotSupportedFilters()
+    public function testThrowIfMessageContainsNotSupportedFilters(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\LogicException::class);
         $this->expectExceptionMessage('The message filters could be either null or array.');
diff --git a/Tests/Binary/Loader/AbstractDoctrineLoaderTest.php b/Tests/Binary/Loader/AbstractDoctrineLoaderTest.php
index 5ffee29e7..956f34e23 100644
--- a/Tests/Binary/Loader/AbstractDoctrineLoaderTest.php
+++ b/Tests/Binary/Loader/AbstractDoctrineLoaderTest.php
@@ -14,6 +14,7 @@
 use Doctrine\Common\Persistence\ObjectManager;
 use Doctrine\Common\Persistence\ObjectRepository;
 use Liip\ImagineBundle\Binary\Loader\AbstractDoctrineLoader;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -22,12 +23,12 @@
 class AbstractDoctrineLoaderTest extends TestCase
 {
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|ObjectRepository
+     * @var MockObject|ObjectRepository
      */
     private $om;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|AbstractDoctrineLoader
+     * @var MockObject|AbstractDoctrineLoader
      */
     private $loader;
 
@@ -47,7 +48,7 @@ public function setUp()
             ->getMockForAbstractClass();
     }
 
-    public function testFindWithValidObjectFirstHit()
+    public function testFindWithValidObjectFirstHit(): void
     {
         $image = new \stdClass();
 
@@ -72,7 +73,7 @@ public function testFindWithValidObjectFirstHit()
         $this->assertSame('foo', $this->loader->find('/foo/bar'));
     }
 
-    public function testFindWithValidObjectSecondHit()
+    public function testFindWithValidObjectSecondHit(): void
     {
         $image = new \stdClass();
 
@@ -101,7 +102,7 @@ public function testFindWithValidObjectSecondHit()
         $this->assertSame('foo', $this->loader->find('/foo/bar.png'));
     }
 
-    public function testFindWithInvalidObject()
+    public function testFindWithInvalidObject(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
 
diff --git a/Tests/Binary/Loader/ChainLoaderTest.php b/Tests/Binary/Loader/ChainLoaderTest.php
index 57307069b..2ce0b857b 100644
--- a/Tests/Binary/Loader/ChainLoaderTest.php
+++ b/Tests/Binary/Loader/ChainLoaderTest.php
@@ -21,8 +21,8 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpFoundation\File\MimeType\ExtensionGuesser;
 use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser;
-use Symfony\Component\Mime\MimeTypes;
 use Symfony\Component\Mime\MimeTypeGuesserInterface;
+use Symfony\Component\Mime\MimeTypes;
 
 /**
  * @covers \Liip\ImagineBundle\Binary\Loader\ChainLoader
@@ -71,9 +71,6 @@ public static function provideLoadCases(): array
 
     /**
      * @dataProvider provideLoadCases
-     *
-     * @param string $root
-     * @param string $path
      */
     public function testLoad(string $root, string $path): void
     {
@@ -93,8 +90,6 @@ public function provideInvalidPathsData(): array
 
     /**
      * @dataProvider provideInvalidPathsData
-     *
-     * @param string $path
      */
     public function testThrowsIfFileDoesNotExist(string $path): void
     {
@@ -106,8 +101,6 @@ public function testThrowsIfFileDoesNotExist(string $path): void
 
     /**
      * @dataProvider provideInvalidPathsData
-     *
-     * @param string $path
      */
     public function testThrowsIfFileDoesNotExistWithMultipleLoaders(string $path): void
     {
@@ -130,8 +123,6 @@ public function testThrowsIfFileDoesNotExistWithMultipleLoaders(string $path): v
 
     /**
      * @param string[] $paths
-     *
-     * @return FileSystemLocator
      */
     private function getFileSystemLocator(array $paths = []): FileSystemLocator
     {
@@ -141,8 +132,6 @@ private function getFileSystemLocator(array $paths = []): FileSystemLocator
     /**
      * @param string[]           $paths
      * @param FileSystemLoader[] $loaders
-     *
-     * @return ChainLoader
      */
     private function getChainLoader(array $paths = [], array $loaders = null): ChainLoader
     {
@@ -155,11 +144,7 @@ private function getChainLoader(array $paths = [], array $loaders = null): Chain
         return new ChainLoader($loaders);
     }
 
-    /**
-     * @param FileBinary|mixed $return
-     * @param string|null      $message
-     */
-    private function assertValidLoaderFindReturn($return, string $message = ''): void
+    private function assertValidLoaderFindReturn(FileBinary $return, string $message = ''): void
     {
         $this->assertInstanceOf(FileBinary::class, $return, $message);
         $this->assertStringStartsWith('text/', $return->getMimeType(), $message);
diff --git a/Tests/Binary/Loader/FileSystemLoaderTest.php b/Tests/Binary/Loader/FileSystemLoaderTest.php
index feef24dce..1557d7d09 100644
--- a/Tests/Binary/Loader/FileSystemLoaderTest.php
+++ b/Tests/Binary/Loader/FileSystemLoaderTest.php
@@ -19,15 +19,15 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\HttpFoundation\File\MimeType\ExtensionGuesser;
 use Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesser;
-use Symfony\Component\Mime\MimeTypes;
 use Symfony\Component\Mime\MimeTypeGuesserInterface;
+use Symfony\Component\Mime\MimeTypes;
 
 /**
  * @covers \Liip\ImagineBundle\Binary\Loader\FileSystemLoader
  */
 class FileSystemLoaderTest extends TestCase
 {
-    public function testConstruction()
+    public function testConstruction(): void
     {
         $loader = $this->getFileSystemLoader();
 
@@ -41,7 +41,7 @@ public function testConstruction()
      * @param $mimeGuesser
      * @param $extensionGuesser
      */
-    public function testThrowsIfConstructedWithWrongTypeArguments($expectedMessage, $mimeGuesser, $extensionGuesser)
+    public function testThrowsIfConstructedWithWrongTypeArguments($expectedMessage, $mimeGuesser, $extensionGuesser): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage($expectedMessage);
@@ -49,30 +49,30 @@ public function testThrowsIfConstructedWithWrongTypeArguments($expectedMessage,
         new FileSystemLoader(
             $mimeGuesser,
             $extensionGuesser,
-            $this->getFileSystemLocator( $this->getDefaultDataRoots())
+            $this->getFileSystemLocator($this->getDefaultDataRoots())
         );
     }
 
     /**
      * @return string[][]
      */
-    public static function provideMultipleWrongArgumentsConstructorCases()
+    public static function provideMultipleWrongArgumentsConstructorCases(): array
     {
         return [
             [
                 '$mimeGuesser must be an instance of Symfony\Component\Mime\MimeTypeGuesserInterface or Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface',
                 'foo',
-                'bar'
+                'bar',
             ],
             [
                 '$extensionGuesser must be an instance of Symfony\Component\Mime\MimeTypesInterface or Symfony\Component\HttpFoundation\File\MimeType\ExtensionGuesserInterface',
                 class_exists(MimeTypes::class) ? MimeTypes::getDefault() : MimeTypeGuesser::getInstance(),
-                'bar'
+                'bar',
             ],
         ];
     }
 
-    public function testImplementsLoaderInterface()
+    public function testImplementsLoaderInterface(): void
     {
         $this->assertInstanceOf(LoaderInterface::class, $this->getFileSystemLoader());
     }
@@ -80,7 +80,7 @@ public function testImplementsLoaderInterface()
     /**
      * @return array[]
      */
-    public static function provideLoadCases()
+    public static function provideLoadCases(): array
     {
         $file = pathinfo(__FILE__, PATHINFO_BASENAME);
 
@@ -114,11 +114,8 @@ public static function provideLoadCases()
 
     /**
      * @dataProvider provideLoadCases
-     *
-     * @param string $root
-     * @param string $path
      */
-    public function testLoad($root, $path)
+    public function testLoad(string $root, string $path): void
     {
         $this->assertValidLoaderFindReturn($this->getFileSystemLoader([$root])->find($path));
     }
@@ -126,7 +123,7 @@ public function testLoad($root, $path)
     /**
      * @return string[][]
      */
-    public static function provideMultipleRootLoadCases()
+    public static function provideMultipleRootLoadCases(): array
     {
         $pathsPrepended = [
             realpath(__DIR__.'/../'),
@@ -143,21 +140,20 @@ public static function provideMultipleRootLoadCases()
      * @dataProvider provideMultipleRootLoadCases
      *
      * @param string[] $roots
-     * @param string   $path
      */
-    public function testMultipleRootLoadCases($roots, $path)
+    public function testMultipleRootLoadCases(array $roots, string $path): void
     {
         $this->assertValidLoaderFindReturn($this->getFileSystemLoader($roots)->find($path));
     }
 
-    public function testAllowsEmptyRootPath()
+    public function testAllowsEmptyRootPath(): void
     {
         $loader = $this->getFileSystemLoader([]);
 
         $this->assertInstanceOf(FileSystemLoader::class, $loader);
     }
 
-    public function testThrowsIfRootPathDoesNotExist()
+    public function testThrowsIfRootPathDoesNotExist(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('Root image path not resolvable');
@@ -170,7 +166,7 @@ public function testThrowsIfRootPathDoesNotExist()
     /**
      * @return array[]
      */
-    public function provideOutsideRootPathsData()
+    public function provideOutsideRootPathsData(): array
     {
         return [
             ['../Loader/../../Binary/Loader/../../../Resources/config/routing.yaml'],
@@ -183,7 +179,7 @@ public function provideOutsideRootPathsData()
      *
      * @param string $path
      */
-    public function testThrowsIfRealPathOutsideRootPath($path)
+    public function testThrowsIfRealPathOutsideRootPath($path): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessage('Source image invalid');
@@ -193,12 +189,12 @@ public function testThrowsIfRealPathOutsideRootPath($path)
         $this->assertInstanceOf(FileSystemLoader::class, $loader);
     }
 
-    public function testPathWithDoublePeriodBackStep()
+    public function testPathWithDoublePeriodBackStep(): void
     {
         $this->assertValidLoaderFindReturn($this->getFileSystemLoader()->find('/../../Binary/Loader/'.pathinfo(__FILE__, PATHINFO_BASENAME)));
     }
 
-    public function testThrowsIfFileDoesNotExist()
+    public function testThrowsIfFileDoesNotExist(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessage('Source image not resolvable');
@@ -210,10 +206,8 @@ public function testThrowsIfFileDoesNotExist()
 
     /**
      * @param string[] $roots
-     *
-     * @return FileSystemLocator
      */
-    private function getFileSystemLocator(array $roots)
+    private function getFileSystemLocator(array $roots): FileSystemLocator
     {
         return new FileSystemLocator($roots);
     }
@@ -221,18 +215,12 @@ private function getFileSystemLocator(array $roots)
     /**
      * @return string[]
      */
-    private function getDefaultDataRoots()
+    private function getDefaultDataRoots(): array
     {
         return [__DIR__];
     }
 
-    /**
-     * @param array                 $roots
-     * @param LocatorInterface|null $locator
-     *
-     * @return FileSystemLoader
-     */
-    private function getFileSystemLoader(array $roots = [], LocatorInterface $locator = null)
+    private function getFileSystemLoader(array $roots = [], LocatorInterface $locator = null): FileSystemLoader
     {
         if (interface_exists(MimeTypeGuesserInterface::class)) {
             $mimeTypes = MimeTypes::getDefault();
@@ -240,22 +228,18 @@ private function getFileSystemLoader(array $roots = [], LocatorInterface $locato
             return new FileSystemLoader(
                 $mimeTypes,
                 $mimeTypes,
-                null !== $locator ? $locator : $this->getFileSystemLocator(\count($roots) ? $roots : $this->getDefaultDataRoots())
+                $locator ?? $this->getFileSystemLocator(\count($roots) ? $roots : $this->getDefaultDataRoots())
             );
         }
 
         return new FileSystemLoader(
             MimeTypeGuesser::getInstance(),
             ExtensionGuesser::getInstance(),
-            null !== $locator ? $locator : $this->getFileSystemLocator(\count($roots) ? $roots : $this->getDefaultDataRoots())
+            $locator ?? $this->getFileSystemLocator(\count($roots) ? $roots : $this->getDefaultDataRoots())
         );
     }
 
-    /**
-     * @param FileBinary|mixed $return
-     * @param string|null      $message
-     */
-    private function assertValidLoaderFindReturn($return, string $message = ''): void
+    private function assertValidLoaderFindReturn(FileBinary $return, string $message = ''): void
     {
         $this->assertInstanceOf(FileBinary::class, $return, $message);
         $this->assertStringStartsWith('text/', $return->getMimeType(), $message);
diff --git a/Tests/Binary/Loader/FlysystemLoaderTest.php b/Tests/Binary/Loader/FlysystemLoaderTest.php
index 70527526d..e070c615f 100644
--- a/Tests/Binary/Loader/FlysystemLoaderTest.php
+++ b/Tests/Binary/Loader/FlysystemLoaderTest.php
@@ -39,22 +39,19 @@ public function setUp()
         $this->flyFilesystem = new Filesystem(new Local($this->fixturesPath));
     }
 
-    /**
-     * @return FlysystemLoader
-     */
-    public function getFlysystemLoader()
+    public function getFlysystemLoader(): FlysystemLoader
     {
         $extensionGuesser = class_exists(MimeTypes::class) ? MimeTypes::getDefault() : ExtensionGuesser::getInstance();
 
         return new FlysystemLoader($extensionGuesser, $this->flyFilesystem);
     }
 
-    public function testShouldImplementLoaderInterface()
+    public function testShouldImplementLoaderInterface(): void
     {
         $this->assertInstanceOf(LoaderInterface::class, $this->getFlysystemLoader());
     }
 
-    public function testThrowsIfConstructedWithWrongTypeArguments()
+    public function testThrowsIfConstructedWithWrongTypeArguments(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('$extensionGuesser must be an instance of Symfony\Component\Mime\MimeTypesInterface or Symfony\Component\HttpFoundation\File\MimeType\ExtensionGuesserInterface');
@@ -65,7 +62,7 @@ public function testThrowsIfConstructedWithWrongTypeArguments()
         );
     }
 
-    public function testReturnImageContentOnFind()
+    public function testReturnImageContentOnFind(): void
     {
         $loader = $this->getFlysystemLoader();
 
@@ -74,7 +71,7 @@ public function testReturnImageContentOnFind()
         );
     }
 
-    public function testThrowsIfInvalidPathGivenOnFind()
+    public function testThrowsIfInvalidPathGivenOnFind(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessageRegExp('{Source image .+ not found}');
diff --git a/Tests/Binary/Loader/StreamLoaderTest.php b/Tests/Binary/Loader/StreamLoaderTest.php
index ebcd8baff..e9f547c99 100644
--- a/Tests/Binary/Loader/StreamLoaderTest.php
+++ b/Tests/Binary/Loader/StreamLoaderTest.php
@@ -19,7 +19,7 @@
  */
 class StreamLoaderTest extends AbstractTest
 {
-    public function testThrowsIfInvalidPathGivenOnFind()
+    public function testThrowsIfInvalidPathGivenOnFind(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessageRegExp('{Source image file://.+ not found.}');
@@ -28,7 +28,7 @@ public function testThrowsIfInvalidPathGivenOnFind()
         $loader->find($this->temporaryPath.'/invalid.jpeg');
     }
 
-    public function testReturnImageContentOnFind()
+    public function testReturnImageContentOnFind(): void
     {
         $loader = new StreamLoader('file://');
 
@@ -37,7 +37,7 @@ public function testReturnImageContentOnFind()
         );
     }
 
-    public function testReturnImageContentWhenStreamContextProvidedOnFind()
+    public function testReturnImageContentWhenStreamContextProvidedOnFind(): void
     {
         $loader = new StreamLoader('file://', stream_context_create());
 
@@ -46,7 +46,7 @@ public function testReturnImageContentWhenStreamContextProvidedOnFind()
         );
     }
 
-    public function testThrowsIfInvalidResourceGivenInConstructor()
+    public function testThrowsIfInvalidResourceGivenInConstructor(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('The given context is no valid resource');
diff --git a/Tests/Binary/Locator/AbstractFileSystemLocatorTest.php b/Tests/Binary/Locator/AbstractFileSystemLocatorTest.php
index d64ff3593..1c33292d9 100644
--- a/Tests/Binary/Locator/AbstractFileSystemLocatorTest.php
+++ b/Tests/Binary/Locator/AbstractFileSystemLocatorTest.php
@@ -13,42 +13,44 @@
 
 use Liip\ImagineBundle\Binary\Locator\FileSystemLocator;
 use Liip\ImagineBundle\Binary\Locator\LocatorInterface;
+use Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException;
+use Liip\ImagineBundle\Exception\InvalidArgumentException;
 use PHPUnit\Framework\TestCase;
 
 abstract class AbstractFileSystemLocatorTest extends TestCase
 {
-    public function testImplementsLocatorInterface()
+    public function testImplementsLocatorInterface(): void
     {
         $this->assertInstanceOf(LocatorInterface::class, new FileSystemLocator());
     }
 
-    public function testThrowsIfEmptyRootPath()
+    public function testThrowsIfEmptyRootPath(): void
     {
-        $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Root image path not resolvable');
 
         $this->getFileSystemLocator('');
     }
 
-    public function testThrowsIfRootPathDoesNotExist()
+    public function testThrowsIfRootPathDoesNotExist(): void
     {
-        $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Root image path not resolvable');
 
         $this->getFileSystemLocator('/a/bad/root/path');
     }
 
-    public function testThrowsIfFileDoesNotExist()
+    public function testThrowsIfFileDoesNotExist(): void
     {
-        $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
+        $this->expectException(NotLoadableException::class);
         $this->expectExceptionMessage('Source image not resolvable');
 
         $this->getFileSystemLocator(__DIR__)->locate('fileNotExist');
     }
 
-    public function testThrowsIfRootPlaceholderInvalid()
+    public function testThrowsIfRootPlaceholderInvalid(): void
     {
-        $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
+        $this->expectException(NotLoadableException::class);
         $this->expectExceptionMessage('Invalid root placeholder "@invalid-placeholder" for path');
 
         $this->getFileSystemLocator(__DIR__)->locate('@invalid-placeholder:file.ext');
@@ -57,18 +59,15 @@ public function testThrowsIfRootPlaceholderInvalid()
     /**
      * @return array[]
      */
-    public static function provideLoadCases()
+    public static function provideLoadCases(): array
     {
         return [];
     }
 
     /**
      * @dataProvider provideLoadCases
-     *
-     * @param string $root
-     * @param string $path
      */
-    public function testLoad($root, $path)
+    public function testLoad(string $root, string $path): void
     {
         $this->assertStringStartsWith(realpath($root.'/../'), $this->getFileSystemLocator($root)->locate($path));
     }
@@ -76,18 +75,15 @@ public function testLoad($root, $path)
     /**
      * @return array[]
      */
-    public static function provideMultipleRootLoadCases()
+    public static function provideMultipleRootLoadCases(): array
     {
         return [];
     }
 
     /**
      * @dataProvider provideMultipleRootLoadCases
-     *
-     * @param string $root
-     * @param string $path
      */
-    public function testMultipleRootLoadCases($root, $path)
+    public function testMultipleRootLoadCases(array $root, string $path): void
     {
         $this->assertNotNull($this->getFileSystemLocator($root)->locate($path));
     }
@@ -95,7 +91,7 @@ public function testMultipleRootLoadCases($root, $path)
     /**
      * @return array[]
      */
-    public function provideOutsideRootPathsData()
+    public function provideOutsideRootPathsData(): array
     {
         return [
             ['../Loader/../../Binary/Loader/../../../Resources/config/routing.yaml'],
@@ -105,12 +101,10 @@ public function provideOutsideRootPathsData()
 
     /**
      * @dataProvider provideOutsideRootPathsData
-     *
-     * @param string $path
      */
-    public function testThrowsIfRealPathOutsideRootPath($path)
+    public function testThrowsIfRealPathOutsideRootPath(string $path): void
     {
-        $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
+        $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('Root image path not resolvable');
 
         $this->getFileSystemLocator($path)->locate($path);
@@ -118,8 +112,6 @@ public function testThrowsIfRealPathOutsideRootPath($path)
 
     /**
      * @param string[]|string $paths
-     *
-     * @return LocatorInterface
      */
-    abstract protected function getFileSystemLocator($paths);
+    abstract protected function getFileSystemLocator($paths): LocatorInterface;
 }
diff --git a/Tests/Binary/Locator/FileSystemInsecureLocatorTest.php b/Tests/Binary/Locator/FileSystemInsecureLocatorTest.php
index ff9de4ca8..e63041702 100644
--- a/Tests/Binary/Locator/FileSystemInsecureLocatorTest.php
+++ b/Tests/Binary/Locator/FileSystemInsecureLocatorTest.php
@@ -19,13 +19,13 @@
  */
 class FileSystemInsecureLocatorTest extends AbstractFileSystemLocatorTest
 {
-    public function testLoadsOnSymbolicLinks()
+    public function testLoadsOnSymbolicLinks(): void
     {
         $loader = $this->getFileSystemLocator($root = realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-02'));
         $this->assertStringStartsWith(realpath($root), $loader->locate('root-01/file.ext'));
     }
 
-    public function testThrowsIfPathHasDoublePeriodBackStep()
+    public function testThrowsIfPathHasDoublePeriodBackStep(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessage('Source image not resolvable');
@@ -33,7 +33,7 @@ public function testThrowsIfPathHasDoublePeriodBackStep()
         $this->getFileSystemLocator(realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-02'))->locate('/../root-01/file.ext');
     }
 
-    public function testRootPlaceholders()
+    public function testRootPlaceholders(): void
     {
         $root01 = realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-01');
         $root02 = realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-02');
@@ -50,7 +50,7 @@ public function testRootPlaceholders()
     /**
      * @return array[]
      */
-    public static function provideLoadCases()
+    public static function provideLoadCases(): array
     {
         $fileName = pathinfo(__FILE__, PATHINFO_BASENAME);
 
@@ -66,7 +66,7 @@ public static function provideLoadCases()
     /**
      * @return array[]
      */
-    public static function provideMultipleRootLoadCases()
+    public static function provideMultipleRootLoadCases(): array
     {
         $prepend = [
             realpath(__DIR__.'/../'),
@@ -81,10 +81,8 @@ public static function provideMultipleRootLoadCases()
 
     /**
      * @param string|string[] $paths
-     *
-     * @return LocatorInterface
      */
-    protected function getFileSystemLocator($paths)
+    protected function getFileSystemLocator($paths): LocatorInterface
     {
         return new FileSystemInsecureLocator((array) $paths);
     }
diff --git a/Tests/Binary/Locator/FileSystemLocatorTest.php b/Tests/Binary/Locator/FileSystemLocatorTest.php
index 8170439b0..48e6b7dbf 100644
--- a/Tests/Binary/Locator/FileSystemLocatorTest.php
+++ b/Tests/Binary/Locator/FileSystemLocatorTest.php
@@ -19,7 +19,7 @@
  */
 class FileSystemLocatorTest extends AbstractFileSystemLocatorTest
 {
-    public function testAllowInvalidPaths()
+    public function testAllowInvalidPaths(): void
     {
         $locator = new FileSystemLocator(['/does/not/exist/foo', '/does/not/exist/bar', $temp = sys_get_temp_dir()], true);
         $roots = (new \ReflectionObject($locator))->getProperty('roots');
@@ -34,7 +34,7 @@ public function testAllowInvalidPaths()
         $this->assertSame($array, $roots->getValue($locator));
     }
 
-    public function testThrowsIfPathHasSymbolicLinksPointOutsideRoot()
+    public function testThrowsIfPathHasSymbolicLinksPointOutsideRoot(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Binary\Loader\NotLoadableException::class);
         $this->expectExceptionMessage('Source image invalid');
@@ -42,7 +42,7 @@ public function testThrowsIfPathHasSymbolicLinksPointOutsideRoot()
         $this->getFileSystemLocator(realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-02'))->locate('root-01/file.ext');
     }
 
-    public function testRootPlaceholders()
+    public function testRootPlaceholders(): void
     {
         $root01 = realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-01');
         $root02 = realpath(__DIR__.'/../../Fixtures/FileSystemLocator/root-02');
@@ -59,7 +59,7 @@ public function testRootPlaceholders()
     /**
      * @return array[]
      */
-    public static function provideLoadCases()
+    public static function provideLoadCases(): array
     {
         $fileName = pathinfo(__FILE__, PATHINFO_BASENAME);
 
@@ -76,7 +76,7 @@ public static function provideLoadCases()
     /**
      * @return array[]
      */
-    public static function provideMultipleRootLoadCases()
+    public static function provideMultipleRootLoadCases(): array
     {
         $prepend = [
             realpath(__DIR__.'/../'),
@@ -91,10 +91,8 @@ public static function provideMultipleRootLoadCases()
 
     /**
      * @param string|string[] $paths
-     *
-     * @return LocatorInterface
      */
-    protected function getFileSystemLocator($paths)
+    protected function getFileSystemLocator($paths): LocatorInterface
     {
         return new FileSystemLocator((array) $paths);
     }
diff --git a/Tests/Binary/SimpleMimeTypeGuesserTest.php b/Tests/Binary/SimpleMimeTypeGuesserTest.php
index a48734343..3a3a8416c 100644
--- a/Tests/Binary/SimpleMimeTypeGuesserTest.php
+++ b/Tests/Binary/SimpleMimeTypeGuesserTest.php
@@ -23,14 +23,14 @@
  */
 class SimpleMimeTypeGuesserTest extends TestCase
 {
-    public function testCouldBeConstructedWithSymfonyMimeTypeGuesserAsFirstArgument()
+    public function testCouldBeConstructedWithSymfonyMimeTypeGuesserAsFirstArgument(): void
     {
         $guesser = $this->getSimpleMimeTypeGuesser();
 
         $this->assertInstanceOf(SimpleMimeTypeGuesser::class, $guesser);
     }
 
-    public function testThrowsIfConstructedWithWrongTypeArguments()
+    public function testThrowsIfConstructedWithWrongTypeArguments(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('$mimeTypeGuesser must be an instance of Symfony\Component\Mime\MimeTypeGuesserInterface or Symfony\Component\HttpFoundation\File\MimeType\MimeTypeGuesserInterface');
@@ -38,7 +38,7 @@ public function testThrowsIfConstructedWithWrongTypeArguments()
         new SimpleMimeTypeGuesser('foo');
     }
 
-    public function testImplementsMimeTypeGuesserInterface()
+    public function testImplementsMimeTypeGuesserInterface(): void
     {
         $this->assertInstanceOf(MimeTypeGuesserInterface::class, $this->getSimpleMimeTypeGuesser());
     }
@@ -46,7 +46,7 @@ public function testImplementsMimeTypeGuesserInterface()
     /**
      * @return array[]
      */
-    public static function provideImageData()
+    public static function provideImageData(): array
     {
         return [
             'gif' => [__DIR__.'/../Fixtures/assets/cats.gif', 'image/gif'],
@@ -65,15 +65,12 @@ public static function provideImageData()
      *
      * @throws \Exception
      */
-    public function testGuessMimeType($fileName, $mimeType)
+    public function testGuessMimeType($fileName, $mimeType): void
     {
         $this->assertSame($mimeType, $this->getSimpleMimeTypeGuesser()->guess(file_get_contents($fileName)));
     }
 
-    /**
-     * @return SimpleMimeTypeGuesser
-     */
-    private function getSimpleMimeTypeGuesser()
+    private function getSimpleMimeTypeGuesser(): SimpleMimeTypeGuesser
     {
         if (interface_exists(SymfonyMimeTypeGuesserInterface::class)) {
             return new SimpleMimeTypeGuesser(MimeTypes::getDefault());
diff --git a/Tests/Component/Console/Style/ImagineStyleTest.php b/Tests/Component/Console/Style/ImagineStyleTest.php
index ed65514c8..e01dc6d55 100644
--- a/Tests/Component/Console/Style/ImagineStyleTest.php
+++ b/Tests/Component/Console/Style/ImagineStyleTest.php
@@ -32,7 +32,7 @@ public function testText(string $format, array $replacements): void
         $style = $this->createImagineStyle($output = $this->createBufferedOutput());
         $style->text($format, $replacements);
 
-        $this->assertContains(vsprintf($format, $replacements), $output->getBuffer());
+        $this->assertStringContainsString(vsprintf($format, $replacements), $output->getBuffer());
     }
 
     public static function provideTextData(): Generator
@@ -51,7 +51,7 @@ public function testTextWithoutDecoration(string $format, array $replacements):
         $style = $this->createImagineStyle($output = $this->createBufferedOutput(), false);
         $style->text($format, $replacements);
 
-        $this->assertContains(strip_tags(vsprintf($format, $replacements)), $output->getBuffer());
+        $this->assertStringContainsString(strip_tags(vsprintf($format, $replacements)), $output->getBuffer());
     }
 
     public static function provideTextWithoutDecorationData(): Generator
@@ -67,7 +67,7 @@ public function testLine(string $format, array $replacements): void
         $style = $this->createImagineStyle($output = $this->createBufferedOutput());
         $style->line($format, $replacements);
 
-        $this->assertContains(vsprintf($format, $replacements).PHP_EOL, $output->getBuffer());
+        $this->assertStringContainsString(vsprintf($format, $replacements).PHP_EOL, $output->getBuffer());
     }
 
     public static function provideLineData(): Generator
@@ -85,7 +85,7 @@ public function testNewline(int $newlineCount, string $separator): void
         $style->newline($newlineCount);
         $style->text($separator);
 
-        $this->assertContains(sprintf('%1$s%2$s%1$s', $separator, str_repeat(PHP_EOL, $newlineCount)), $output->getBuffer());
+        $this->assertStringContainsString(sprintf('%1$s%2$s%1$s', $separator, str_repeat(PHP_EOL, $newlineCount)), $output->getBuffer());
     }
 
     public static function provideNewlineData(): Generator
@@ -117,7 +117,7 @@ public function testTitle(string $title, string $type = null, bool $decoration):
             }
         }
 
-        $this->assertContains($expected, $output->getBuffer());
+        $this->assertStringContainsString($expected, $output->getBuffer());
     }
 
     public static function provideTitleData(): Generator
@@ -128,8 +128,8 @@ public static function provideTitleData(): Generator
         ];
 
         foreach ($titles as $type => $title) {
-            yield [$title, is_string($type) ? $type : null, true];
-            yield [$title, is_string($type) ? $type : null, false];
+            yield [$title, \is_string($type) ? $type : null, true];
+            yield [$title, \is_string($type) ? $type : null, false];
         }
     }
 
@@ -141,14 +141,14 @@ public function testBlockTypes(string $type, string $expectedFormat, string $for
         $blockMethod = sprintf('%sBlock', $type);
         $style = $this->createImagineStyle($output = $this->createBufferedOutput(), $decoration);
 
-        if (!is_callable([$style, $blockMethod])) {
+        if (!\is_callable([$style, $blockMethod])) {
             static::fail(sprintf('Required method "%s" for "%s" block type is not callable!', $blockMethod, $type));
         }
 
         $style->{$blockMethod}($format, $replacements);
         $compiled = vsprintf(strip_tags($format), $replacements);
 
-        $this->assertContains(sprintf($expectedFormat, $compiled), $output->getBuffer());
+        $this->assertStringContainsString(sprintf($expectedFormat, $compiled), $output->getBuffer());
     }
 
     public static function provideBlockTypesData(): Generator
@@ -178,11 +178,11 @@ public static function provideBlockTypesData(): Generator
     public function testStatus(string $status, string $fg = null, string $bg = null): void
     {
         $style = $this->createImagineStyle($output = $this->createBufferedOutput());
-        $style->status($status, $fg, $bg);
+        $style->status($status, $fg);
 
-        $this->assertContains($fg ?: 'default', $output->getBuffer());
-        $this->assertContains($bg ?: 'default', $output->getBuffer());
-        $this->assertContains(sprintf('(%s)', $status), strip_tags($output->getBuffer()));
+        $this->assertStringContainsString($fg ?: 'default', $output->getBuffer());
+        $this->assertStringContainsString($bg ?: 'default', $output->getBuffer());
+        $this->assertStringContainsString(sprintf('(%s)', $status), strip_tags($output->getBuffer()));
     }
 
     public static function provideStatusData(): Generator
@@ -204,9 +204,9 @@ public function testGroup(string $item, string $group, string $fg = null, string
         $style = $this->createImagineStyle($output = $this->createBufferedOutput());
         $style->group($item, $group, $fg, $bg);
 
-        $this->assertContains($fg ?: 'default', $output->getBuffer());
-        $this->assertContains($bg ?: 'default', $output->getBuffer());
-        $this->assertContains(sprintf('%s[%s]', $item, $group), strip_tags($output->getBuffer()));
+        $this->assertStringContainsString($fg ?: 'default', $output->getBuffer());
+        $this->assertStringContainsString($bg ?: 'default', $output->getBuffer());
+        $this->assertStringContainsString(sprintf('%s[%s]', $item, $group), strip_tags($output->getBuffer()));
     }
 
     public static function provideGroupData(): Generator
diff --git a/Tests/Config/FilterSetBuilderTest.php b/Tests/Config/FilterSetBuilderTest.php
index be05c5e9d..42f05ec3b 100644
--- a/Tests/Config/FilterSetBuilderTest.php
+++ b/Tests/Config/FilterSetBuilderTest.php
@@ -18,6 +18,7 @@
 use Liip\ImagineBundle\Factory\Config\FilterFactoryInterface;
 use Liip\ImagineBundle\Factory\Config\StackFactory;
 use Liip\ImagineBundle\Factory\Config\StackFactoryInterface;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -26,12 +27,12 @@
 class FilterSetBuilderTest extends TestCase
 {
     /**
-     * @var StackFactory|\PHPUnit_Framework_MockObject_MockObject
+     * @var StackFactory|MockObject
      */
     private $filterSetFactoryMock;
 
     /**
-     * @var FilterFactoryCollection|\PHPUnit_Framework_MockObject_MockObject
+     * @var FilterFactoryCollection|MockObject
      */
     private $filterFactoryCollectionMock;
 
@@ -47,7 +48,7 @@ protected function setUp()
         $this->model = new StackBuilder($this->filterSetFactoryMock, $this->filterFactoryCollectionMock);
     }
 
-    public function testBuildWithEmptyFilters()
+    public function testBuildWithEmptyFilters(): void
     {
         $name = 'foo';
         $dataLoader = 'bar';
@@ -72,7 +73,7 @@ public function testBuildWithEmptyFilters()
         $this->assertSame($filterSetMock, $filterSet);
     }
 
-    public function testBuildWithFilters()
+    public function testBuildWithFilters(): void
     {
         $name = 'foo';
         $dataLoader = 'bar';
diff --git a/Tests/Config/FilterSetCollectionTest.php b/Tests/Config/FilterSetCollectionTest.php
index 18306728b..8001437ea 100644
--- a/Tests/Config/FilterSetCollectionTest.php
+++ b/Tests/Config/FilterSetCollectionTest.php
@@ -21,7 +21,7 @@
  */
 class FilterSetCollectionTest extends TestCase
 {
-    public function testGetFilterSets()
+    public function testGetFilterSets(): void
     {
         $filterSetName = 'foo';
         $filterSetData = ['bar'];
diff --git a/Tests/Config/FilterSetTest.php b/Tests/Config/FilterSetTest.php
index 9be932651..a4517199f 100644
--- a/Tests/Config/FilterSetTest.php
+++ b/Tests/Config/FilterSetTest.php
@@ -20,7 +20,7 @@
  */
 class FilterSetTest extends TestCase
 {
-    public function testSetFiltersWithInvalidFilterThrowsException()
+    public function testSetFiltersWithInvalidFilterThrowsException(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('Unknown filter provided.');
@@ -28,21 +28,17 @@ public function testSetFiltersWithInvalidFilterThrowsException()
         $this->buildFilterSet(['not_a_filter']);
     }
 
-    public function testSetFiltersWithValidFilterSuccess()
+    public function testSetFiltersWithValidFilterSuccess(): void
     {
         $filterMock = $this->createMock(FilterInterface::class);
         $stack = $this->buildFilterSet([$filterMock]);
 
-        $this->assertInstanceOf(Stack::class, $stack);
         $this->assertSame('filter_name', $stack->getName());
         $this->assertSame('data_loader', $stack->getDataLoader());
         $this->assertSame(42, $stack->getQuality());
         $this->assertSame([$filterMock], $stack->getFilters());
     }
 
-    /**
-     * @param array $filters
-     */
     private function buildFilterSet(array $filters): Stack
     {
         return new Stack('filter_name', 'data_loader', 42, $filters);
diff --git a/Tests/DependencyInjection/Compiler/AbstractCompilerPassTest.php b/Tests/DependencyInjection/Compiler/AbstractCompilerPassTest.php
index fb3b83d08..0f7d99794 100644
--- a/Tests/DependencyInjection/Compiler/AbstractCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/AbstractCompilerPassTest.php
@@ -12,13 +12,14 @@
 namespace Liip\ImagineBundle\Tests\DependencyInjection\Compiler;
 
 use Liip\ImagineBundle\DependencyInjection\Compiler\AbstractCompilerPass;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\DependencyInjection\Compiler\AbstractCompilerPass
  */
 class AbstractCompilerPassTest extends AbstractCompilerPassTestCase
 {
-    public function testCompilerLogging()
+    public function testCompilerLogging(): void
     {
         $pass = $this->createAbstractCompilerPassMock();
 
@@ -36,7 +37,7 @@ public function testCompilerLogging()
     /**
      * @param string[] $methods
      *
-     * @return \PHPUnit_Framework_MockObject_MockObject|AbstractCompilerPass
+     * @return MockObject|AbstractCompilerPass
      */
     private function createAbstractCompilerPassMock(array $methods = [])
     {
diff --git a/Tests/DependencyInjection/Compiler/AbstractCompilerPassTestCase.php b/Tests/DependencyInjection/Compiler/AbstractCompilerPassTestCase.php
index 1ed1864e0..828abf79f 100644
--- a/Tests/DependencyInjection/Compiler/AbstractCompilerPassTestCase.php
+++ b/Tests/DependencyInjection/Compiler/AbstractCompilerPassTestCase.php
@@ -13,6 +13,7 @@
 
 use Liip\ImagineBundle\DependencyInjection\Compiler\AbstractCompilerPass;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
 
@@ -21,12 +22,7 @@
  */
 class AbstractCompilerPassTestCase extends AbstractTest
 {
-    /**
-     * @param array $tags
-     *
-     * @return Definition
-     */
-    protected function createDefinition(array $tags = [])
+    protected function createDefinition(array $tags = []): Definition
     {
         $definition = new Definition();
 
@@ -39,10 +35,8 @@ protected function createDefinition(array $tags = [])
 
     /**
      * @param Definition[] $definitions
-     *
-     * @return ContainerBuilder
      */
-    protected function createContainerBuilder(array $definitions = [])
+    protected function createContainerBuilder(array $definitions = []): ContainerBuilder
     {
         $container = new ContainerBuilder();
 
@@ -57,7 +51,7 @@ protected function createContainerBuilder(array $definitions = [])
      * @param string[]     $methods
      * @param Definition[] $definitions
      *
-     * @return ContainerBuilder|\PHPUnit_Framework_MockObject_MockObject
+     * @return ContainerBuilder|MockObject
      */
     protected function createContainerBuilderMock(array $methods = [], array $definitions = [])
     {
@@ -74,10 +68,9 @@ protected function createContainerBuilderMock(array $methods = [], array $defini
     }
 
     /**
-     * @param \PHPUnit_Framework_MockObject_MockObject $container
-     * @param mixed[]                                  ...$expectedArguments
+     * @param mixed[] ...$expectedArguments
      */
-    protected function expectContainerLogMethodCalledOnce(\PHPUnit_Framework_MockObject_MockObject $container, ...$expectedArguments): void
+    protected function expectContainerLogMethodCalledOnce(MockObject $container, ...$expectedArguments): void
     {
         $expectation = $container
             ->expects($this->once())
@@ -90,27 +83,17 @@ protected function expectContainerLogMethodCalledOnce(\PHPUnit_Framework_MockObj
         }
     }
 
-    /**
-     * @param Definition  $definition
-     * @param string|null $message
-     */
-    protected function assertDefinitionMethodCallsNone(Definition $definition, $message = '')
+    protected function assertDefinitionMethodCallsNone(Definition $definition, string $message = ''): void
     {
         $this->assertDefinitionMethodCallCount(0, $definition, $message);
     }
 
-    /**
-     * @param int         $expect
-     * @param Definition  $definition
-     * @param string|null $message
-     */
-    protected function assertDefinitionMethodCallCount($expect, Definition $definition, $message = '')
+    protected function assertDefinitionMethodCallCount(int $expect, Definition $definition, string $message = ''): void
     {
         $this->assertCount($expect, $definition->getMethodCalls(), $message);
     }
 
     /**
-     * @param AbstractCompilerPass $pass
      * @param Definition[]|array[] $definitions
      */
     protected function assertContainerLogMethodCalledForCompilerPass(AbstractCompilerPass $pass, array $definitions): void
@@ -122,10 +105,6 @@ protected function assertContainerLogMethodCalledForCompilerPass(AbstractCompile
     }
 
     /**
-     * @param string $definition
-     * @param string $manager
-     * @param array  $tags
-     *
      * @return Definition[]|array[]
      */
     protected function getCompilerPassContainerDefinitions(string $definition, string $manager, array $tags): array
diff --git a/Tests/DependencyInjection/Compiler/FiltersCompilerPassTest.php b/Tests/DependencyInjection/Compiler/FiltersCompilerPassTest.php
index 53caa56c7..13858992f 100644
--- a/Tests/DependencyInjection/Compiler/FiltersCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/FiltersCompilerPassTest.php
@@ -19,7 +19,7 @@
  */
 class FiltersCompilerPassTest extends AbstractCompilerPassTestCase
 {
-    public function testProcess()
+    public function testProcess(): void
     {
         [$d, $m] = $this->getFiltersCompilerPassContainerDefinitions();
 
@@ -32,7 +32,7 @@ public function testProcess()
         $this->assertDefinitionMethodCallCount(1, $m);
     }
 
-    public function testProcessLogging()
+    public function testProcessLogging(): void
     {
         $this->assertContainerLogMethodCalledForCompilerPass(
             new FiltersCompilerPass(),
diff --git a/Tests/DependencyInjection/Compiler/LoadersCompilerPassTest.php b/Tests/DependencyInjection/Compiler/LoadersCompilerPassTest.php
index 845e78a3c..62f4cb1f5 100644
--- a/Tests/DependencyInjection/Compiler/LoadersCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/LoadersCompilerPassTest.php
@@ -19,7 +19,7 @@
  */
 class LoadersCompilerPassTest extends AbstractCompilerPassTestCase
 {
-    public function testProcess()
+    public function testProcess(): void
     {
         [$d, $m] = $this->getLoadersCompilerPassContainerDefinitions();
 
@@ -32,7 +32,7 @@ public function testProcess()
         $this->assertDefinitionMethodCallCount(1, $m);
     }
 
-    public function testProcessLogging()
+    public function testProcessLogging(): void
     {
         $this->assertContainerLogMethodCalledForCompilerPass(
             new LoadersCompilerPass(),
diff --git a/Tests/DependencyInjection/Compiler/MetadataReaderCompilerPassTest.php b/Tests/DependencyInjection/Compiler/MetadataReaderCompilerPassTest.php
index 131cca537..9f4e86cec 100644
--- a/Tests/DependencyInjection/Compiler/MetadataReaderCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/MetadataReaderCompilerPassTest.php
@@ -12,6 +12,7 @@
 namespace Liip\ImagineBundle\Tests\DependencyInjection\Compiler;
 
 use Liip\ImagineBundle\DependencyInjection\Compiler\MetadataReaderCompilerPass;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Definition;
@@ -21,7 +22,7 @@
  */
 class MetadataReaderCompilerPassTest extends TestCase
 {
-    public function testProcessBasedOnExtensionsInEnvironment()
+    public function testProcessBasedOnExtensionsInEnvironment(): void
     {
         [$metadataServiceId, $metadataExifClass, $metadataDefaultClass] = static::getReaderParamAndDefaultAndExifValues();
 
@@ -33,7 +34,7 @@ public function testProcessBasedOnExtensionsInEnvironment()
         $this->assertInstanceOf(\extension_loaded('exif') ? $metadataExifClass : $metadataDefaultClass, $container->get($metadataServiceId));
     }
 
-    public function testProcessWithoutExtExifAddsDefaultReader()
+    public function testProcessWithoutExtExifAddsDefaultReader(): void
     {
         [$metadataServiceId, $metadataExifClass, $metadataDefaultClass] = static::getReaderParamAndDefaultAndExifValues();
 
@@ -46,7 +47,7 @@ public function testProcessWithoutExtExifAddsDefaultReader()
         $this->assertInstanceOf($metadataDefaultClass, $container->get($metadataServiceId));
     }
 
-    public function testProcessWithExtExifKeepsExifReader()
+    public function testProcessWithExtExifKeepsExifReader(): void
     {
         [$metadataServiceId, $metadataExifClass] = static::getReaderParamAndDefaultAndExifValues();
 
@@ -59,7 +60,7 @@ public function testProcessWithExtExifKeepsExifReader()
         $this->assertInstanceOf($metadataExifClass, $container->get($metadataServiceId));
     }
 
-    public function testDoesNotOverrideCustomReaderWhenExifNotAvailable()
+    public function testDoesNotOverrideCustomReaderWhenExifNotAvailable(): void
     {
         [$metadataServiceId] = static::getReaderParamAndDefaultAndExifValues();
 
@@ -72,13 +73,7 @@ public function testDoesNotOverrideCustomReaderWhenExifNotAvailable()
         $this->assertInstanceOf('stdClass', $container->get($metadataServiceId));
     }
 
-    /**
-     * @param \ReflectionClass $r
-     * @param string           $p
-     *
-     * @return string
-     */
-    private static function getVisibilityRestrictedStaticProperty(\ReflectionClass $r, $p)
+    private static function getVisibilityRestrictedStaticProperty(\ReflectionClass $r, string $p): string
     {
         $property = $r->getProperty($p);
         $property->setAccessible(true);
@@ -91,7 +86,7 @@ private static function getVisibilityRestrictedStaticProperty(\ReflectionClass $
      *
      * @return mixed[]
      */
-    private static function getReaderParamAndDefaultAndExifValues()
+    private static function getReaderParamAndDefaultAndExifValues(): array
     {
         $r = new \ReflectionClass(MetadataReaderCompilerPass::class);
 
@@ -103,11 +98,9 @@ private static function getReaderParamAndDefaultAndExifValues()
     }
 
     /**
-     * @param bool $isExifExtensionLoaded
-     *
-     * @return \PHPUnit_Framework_MockObject_MockObject|MetadataReaderCompilerPass
+     * @return MockObject|MetadataReaderCompilerPass
      */
-    private function getMetadataReaderCompilerPass($isExifExtensionLoaded)
+    private function getMetadataReaderCompilerPass(bool $isExifExtensionLoaded)
     {
         $mock = $this->getMockBuilder(MetadataReaderCompilerPass::class)
             ->setMethods(['isExifExtensionLoaded'])
diff --git a/Tests/DependencyInjection/Compiler/PostProcessorsCompilerPassTest.php b/Tests/DependencyInjection/Compiler/PostProcessorsCompilerPassTest.php
index 9f5ba3252..839788fb7 100644
--- a/Tests/DependencyInjection/Compiler/PostProcessorsCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/PostProcessorsCompilerPassTest.php
@@ -19,7 +19,7 @@
  */
 class PostProcessorsCompilerPassTest extends AbstractCompilerPassTestCase
 {
-    public function testProcess()
+    public function testProcess(): void
     {
         [$d, $m] = $this->getPostProcessorsCompilerPassContainerDefinitions();
 
@@ -32,7 +32,7 @@ public function testProcess()
         $this->assertDefinitionMethodCallCount(1, $m);
     }
 
-    public function testProcessLogging()
+    public function testProcessLogging(): void
     {
         $this->assertContainerLogMethodCalledForCompilerPass(
             new PostProcessorsCompilerPass(),
diff --git a/Tests/DependencyInjection/Compiler/ResolversCompilerPassTest.php b/Tests/DependencyInjection/Compiler/ResolversCompilerPassTest.php
index 015ff377a..d65de88e8 100644
--- a/Tests/DependencyInjection/Compiler/ResolversCompilerPassTest.php
+++ b/Tests/DependencyInjection/Compiler/ResolversCompilerPassTest.php
@@ -19,7 +19,7 @@
  */
 class ResolversCompilerPassTest extends AbstractCompilerPassTestCase
 {
-    public function testProcess()
+    public function testProcess(): void
     {
         [$d, $m] = $this->getResolversCompilerPassContainerDefinitions();
 
@@ -32,7 +32,7 @@ public function testProcess()
         $this->assertDefinitionMethodCallCount(1, $m);
     }
 
-    public function testProcessLogging()
+    public function testProcessLogging(): void
     {
         $this->assertContainerLogMethodCalledForCompilerPass(
             new ResolversCompilerPass(),
diff --git a/Tests/DependencyInjection/ConfigurationTest.php b/Tests/DependencyInjection/ConfigurationTest.php
index 70c481b73..49edba3b4 100644
--- a/Tests/DependencyInjection/ConfigurationTest.php
+++ b/Tests/DependencyInjection/ConfigurationTest.php
@@ -27,28 +27,28 @@
  */
 class ConfigurationTest extends TestCase
 {
-    public function testImplementsConfigurationInterface()
+    public function testImplementsConfigurationInterface(): void
     {
         $rc = new \ReflectionClass(Configuration::class);
 
         $this->assertTrue($rc->implementsInterface(ConfigurationInterface::class));
     }
 
-    public function testTemplatingSupportIsEnabledByDefault()
+    public function testTemplatingSupportIsEnabledByDefault(): void
     {
         $config = $this->processConfiguration(new Configuration([], []), []);
 
         $this->assertTrue($config['templating']);
     }
 
-    public function testCouldBeConstructedWithResolversAndLoadersFactoriesAsArguments()
+    public function testCouldBeConstructedWithResolversAndLoadersFactoriesAsArguments(): void
     {
         $config = new Configuration([], []);
 
         $this->assertInstanceOf(Configuration::class, $config);
     }
 
-    public function testInjectLoaderFactoryConfig()
+    public function testInjectLoaderFactoryConfig(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -78,7 +78,7 @@ public function testInjectLoaderFactoryConfig()
         $this->assertSame('theValue', $config['loaders']['aLoader']['foo']['foo_option']);
     }
 
-    public function testAllowToUseLoaderFactorySeveralTimes()
+    public function testAllowToUseLoaderFactorySeveralTimes(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -111,7 +111,7 @@ public function testAllowToUseLoaderFactorySeveralTimes()
         $this->assertArrayHasKey('anotherLoader', $config['loaders']);
     }
 
-    public function testSetFilesystemLoaderAsDefaultLoaderIfNotDefined()
+    public function testSetFilesystemLoaderAsDefaultLoaderIfNotDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -133,7 +133,7 @@ public function testSetFilesystemLoaderAsDefaultLoaderIfNotDefined()
         $this->assertArrayHasKey('filesystem', $config['loaders']['default']);
     }
 
-    public function testSetFilesystemLoaderAsDefaultLoaderIfNull()
+    public function testSetFilesystemLoaderAsDefaultLoaderIfNull(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -154,7 +154,7 @@ public function testSetFilesystemLoaderAsDefaultLoaderIfNull()
         $this->assertArrayHasKey('filesystem', $config['loaders']['default']);
     }
 
-    public function testThrowIfLoadersNotArray()
+    public function testThrowIfLoadersNotArray(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('Loaders has to be array');
@@ -174,7 +174,7 @@ public function testThrowIfLoadersNotArray()
         );
     }
 
-    public function testSetFilesystemLoaderAsDefaultIfLoadersSectionNotDefined()
+    public function testSetFilesystemLoaderAsDefaultIfLoadersSectionNotDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -193,7 +193,7 @@ public function testSetFilesystemLoaderAsDefaultIfLoadersSectionNotDefined()
         $this->assertArrayHasKey('filesystem', $config['loaders']['default']);
     }
 
-    public function testSetWebPathResolversAsDefaultIfResolversSectionNotDefined()
+    public function testSetWebPathResolversAsDefaultIfResolversSectionNotDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -212,7 +212,7 @@ public function testSetWebPathResolversAsDefaultIfResolversSectionNotDefined()
         $this->assertArrayHasKey('web_path', $config['resolvers']['default']);
     }
 
-    public function testShouldNotOverwriteDefaultLoaderIfDefined()
+    public function testShouldNotOverwriteDefaultLoaderIfDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -240,7 +240,7 @@ public function testShouldNotOverwriteDefaultLoaderIfDefined()
         $this->assertArrayHasKey('foo', $config['loaders']['default']);
     }
 
-    public function testInjectResolverFactoryConfig()
+    public function testInjectResolverFactoryConfig(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -269,7 +269,7 @@ public function testInjectResolverFactoryConfig()
         $this->assertSame('theValue', $config['resolvers']['aResolver']['bar']['bar_option']);
     }
 
-    public function testAllowToUseResolverFactorySeveralTimes()
+    public function testAllowToUseResolverFactorySeveralTimes(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -302,7 +302,7 @@ public function testAllowToUseResolverFactorySeveralTimes()
         $this->assertArrayHasKey('anotherResolver', $config['resolvers']);
     }
 
-    public function testSetWebPathAsDefaultResolverIfNotDefined()
+    public function testSetWebPathAsDefaultResolverIfNotDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -323,7 +323,7 @@ public function testSetWebPathAsDefaultResolverIfNotDefined()
         $this->assertArrayHasKey('web_path', $config['resolvers']['default']);
     }
 
-    public function testSetWebPathAsDefaultResolverIfNull()
+    public function testSetWebPathAsDefaultResolverIfNull(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -343,7 +343,7 @@ public function testSetWebPathAsDefaultResolverIfNull()
         $this->assertArrayHasKey('web_path', $config['resolvers']['default']);
     }
 
-    public function testThrowsIfResolversNotArray()
+    public function testThrowsIfResolversNotArray(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('Resolvers has to be array');
@@ -366,7 +366,7 @@ public function testThrowsIfResolversNotArray()
         $this->assertArrayHasKey('web_path', $config['resolvers']['default']);
     }
 
-    public function testShouldNotOverwriteDefaultResolverIfDefined()
+    public function testShouldNotOverwriteDefaultResolverIfDefined(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -394,7 +394,7 @@ public function testShouldNotOverwriteDefaultResolverIfDefined()
         $this->assertArrayHasKey('bar', $config['resolvers']['default']);
     }
 
-    public function testNewFilterQualitySettings()
+    public function testNewFilterQualitySettings(): void
     {
         $config = $this->processConfiguration(
             new Configuration(
@@ -427,13 +427,7 @@ public function testNewFilterQualitySettings()
         $this->assertSame(PNG_ALL_FILTERS, $config['filter_sets']['test']['png_compression_filter']);
     }
 
-    /**
-     * @param ConfigurationInterface $configuration
-     * @param array                  $configs
-     *
-     * @return array
-     */
-    protected function processConfiguration(ConfigurationInterface $configuration, array $configs)
+    protected function processConfiguration(ConfigurationInterface $configuration, array $configs): array
     {
         $processor = new Processor();
 
@@ -447,12 +441,12 @@ public function create(ContainerBuilder $container, $loaderName, array $config)
     {
     }
 
-    public function getName()
+    public function getName(): string
     {
         return 'foo';
     }
 
-    public function addConfiguration(ArrayNodeDefinition $builder)
+    public function addConfiguration(ArrayNodeDefinition $builder): void
     {
         $builder
             ->children()
@@ -467,12 +461,12 @@ public function create(ContainerBuilder $container, $resolverName, array $config
     {
     }
 
-    public function getName()
+    public function getName(): string
     {
         return 'bar';
     }
 
-    public function addConfiguration(ArrayNodeDefinition $builder)
+    public function addConfiguration(ArrayNodeDefinition $builder): void
     {
         $builder
             ->children()
diff --git a/Tests/DependencyInjection/Factory/FactoryTestCase.php b/Tests/DependencyInjection/Factory/FactoryTestCase.php
index 62f53f895..b6837b28b 100644
--- a/Tests/DependencyInjection/Factory/FactoryTestCase.php
+++ b/Tests/DependencyInjection/Factory/FactoryTestCase.php
@@ -17,10 +17,7 @@
 
 abstract class FactoryTestCase extends TestCase
 {
-    /**
-     * @param Definition $definition
-     */
-    protected function assertInstanceOfChildDefinition(Definition $definition)
+    protected function assertInstanceOfChildDefinition(Definition $definition): void
     {
         $this->assertInstanceOf(ChildDefinition::class, $definition);
     }
diff --git a/Tests/DependencyInjection/Factory/Loader/ChainLoaderFactoryTest.php b/Tests/DependencyInjection/Factory/Loader/ChainLoaderFactoryTest.php
index a3ebac216..b0c942fb3 100644
--- a/Tests/DependencyInjection/Factory/Loader/ChainLoaderFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Loader/ChainLoaderFactoryTest.php
@@ -18,6 +18,7 @@
 use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * @covers \Liip\ImagineBundle\DependencyInjection\Factory\Loader\ChainLoaderFactory
@@ -56,7 +57,7 @@ public function testCreateLoaderDefinition(): void
         $this->assertSame('liip_imagine.binary.loader.prototype.chain', $loaderDefinition->getParent());
 
         foreach ($loaderDefinition->getArgument(0) as $reference) {
-            $this->assertInstanceOf('\Symfony\Component\DependencyInjection\Reference', $reference);
+            $this->assertInstanceOf(Reference::class, $reference);
         }
     }
 
@@ -83,12 +84,6 @@ public function testProcessOptionsOnAddConfiguration(): void
         $this->assertSame(['foo', 'bar'], $config['loaders']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
     private function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         return (new Processor())->process($treeBuilder->buildTree(), $configs);
diff --git a/Tests/DependencyInjection/Factory/Loader/FileSystemLoaderFactoryTest.php b/Tests/DependencyInjection/Factory/Loader/FileSystemLoaderFactoryTest.php
index ee95e50b1..13f6e648d 100644
--- a/Tests/DependencyInjection/Factory/Loader/FileSystemLoaderFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Loader/FileSystemLoaderFactoryTest.php
@@ -26,24 +26,24 @@
  */
 class FileSystemLoaderFactoryTest extends FactoryTestCase
 {
-    public function testImplementsLoaderFactoryInterface()
+    public function testImplementsLoaderFactoryInterface(): void
     {
         $this->assertInstanceOf(LoaderFactoryInterface::class, new FileSystemLoaderFactory());
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $this->assertInstanceOf(FileSystemLoaderFactory::class, new FileSystemLoaderFactory());
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $loader = new FileSystemLoaderFactory();
 
         $this->assertSame('filesystem', $loader->getName());
     }
 
-    public function testCreateLoaderDefinitionOnCreate()
+    public function testCreateLoaderDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -70,7 +70,7 @@ public function testCreateLoaderDefinitionOnCreate()
         $this->assertFalse($loaderDefinition->getArgument(2)->getArgument(1));
     }
 
-    public function testCreateLoaderDefinitionWithUnresolvableRoots()
+    public function testCreateLoaderDefinitionWithUnresolvableRoots(): void
     {
         $container = new ContainerBuilder();
 
@@ -97,7 +97,7 @@ public function testCreateLoaderDefinitionWithUnresolvableRoots()
         $this->assertTrue($loaderDefinition->getArgument(2)->getArgument(1));
     }
 
-    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadata()
+    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadata(): void
     {
         $fooBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/FooBundle');
         $barBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/BarBundle');
@@ -133,7 +133,7 @@ public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadat
         $this->assertSame($expected, $container->getDefinition('liip_imagine.binary.loader.the_loader_name')->getArgument(2)->getArgument(0));
     }
 
-    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadataAndBlacklisting()
+    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadataAndBlacklisting(): void
     {
         $fooBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/FooBundle');
         $barBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/BarBundle');
@@ -170,7 +170,7 @@ public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadat
         $this->assertSame($expected, $container->getDefinition('liip_imagine.binary.loader.the_loader_name')->getArgument(2)->getArgument(0));
     }
 
-    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadataAndWhitelisting()
+    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadataAndWhitelisting(): void
     {
         $fooBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/FooBundle');
         $barBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/BarBundle');
@@ -207,7 +207,7 @@ public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingMetadat
         $this->assertSame($expected, $container->getDefinition('liip_imagine.binary.loader.the_loader_name')->getArgument(2)->getArgument(0));
     }
 
-    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingNamedObj()
+    public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingNamedObj(): void
     {
         $fooBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/FooBundle');
         $barBundleRootPath = realpath(__DIR__.'/../../../Functional/Fixtures/BarBundle');
@@ -239,7 +239,7 @@ public function testCreateLoaderDefinitionOnCreateWithBundlesEnabledUsingNamedOb
         $this->assertSame($expected, $container->getDefinition('liip_imagine.binary.loader.the_loader_name')->getArgument(2)->getArgument(0));
     }
 
-    public function testAbleToCreateTwoDistinctLoaders()
+    public function testAbleToCreateTwoDistinctLoaders(): void
     {
         $container = new ContainerBuilder();
 
@@ -273,7 +273,7 @@ public function testAbleToCreateTwoDistinctLoaders()
         );
     }
 
-    public function testThrowsExceptionOnCreateWithBundlesEnabledUsingInvalidNamedObj()
+    public function testThrowsExceptionOnCreateWithBundlesEnabledUsingInvalidNamedObj(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('Unable to resolve bundle "ThisBundleDoesNotExistPleaseNoOneNameTheirObjectThisInThisScopeOrTheGlobalScopeIMeanAreYouInsane" while auto-registering bundle resource paths');
@@ -294,7 +294,7 @@ public function testThrowsExceptionOnCreateWithBundlesEnabledUsingInvalidNamedOb
         ]);
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedDataRoot = ['theDataRoot'];
 
@@ -316,7 +316,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedDataRoot, $config['data_root']);
     }
 
-    public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
+    public function testAddDefaultOptionsIfNotSetOnAddConfiguration(): void
     {
         $expectedDataRoot = [SymfonyFramework::getContainerResolvableRootWebPath()];
 
@@ -336,7 +336,7 @@ public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
         $this->assertSame($expectedDataRoot, $config['data_root']);
     }
 
-    public function testAddAsScalarExpectingArrayNormalizationOfConfiguration()
+    public function testAddAsScalarExpectingArrayNormalizationOfConfiguration(): void
     {
         $expectedDataRoot = [SymfonyFramework::getContainerResolvableRootWebPath()];
 
@@ -358,13 +358,7 @@ public function testAddAsScalarExpectingArrayNormalizationOfConfiguration()
         $this->assertSame($expectedDataRoot, $config['data_root']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/Factory/Loader/FlysystemLoaderFactoryTest.php b/Tests/DependencyInjection/Factory/Loader/FlysystemLoaderFactoryTest.php
index 6dc9fea49..37658faf4 100644
--- a/Tests/DependencyInjection/Factory/Loader/FlysystemLoaderFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Loader/FlysystemLoaderFactoryTest.php
@@ -34,28 +34,28 @@ public function setUp()
         }
     }
 
-    public function testImplementsLoaderFactoryInterface()
+    public function testImplementsLoaderFactoryInterface(): void
     {
         $rc = new \ReflectionClass(FlysystemLoaderFactory::class);
 
         $this->assertTrue($rc->implementsInterface(LoaderFactoryInterface::class));
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $loader = new FlysystemLoaderFactory();
 
         $this->assertInstanceOf(FlysystemLoaderFactory::class, $loader);
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $loader = new FlysystemLoaderFactory();
 
         $this->assertSame('flysystem', $loader->getName());
     }
 
-    public function testCreateLoaderDefinitionOnCreate()
+    public function testCreateLoaderDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -72,10 +72,10 @@ public function testCreateLoaderDefinitionOnCreate()
         $this->assertSame('liip_imagine.binary.loader.prototype.flysystem', $loaderDefinition->getParent());
 
         $reference = $loaderDefinition->getArgument(1);
-        $this->assertSame('flyfilesystemservice', "$reference");
+        $this->assertSame('flyfilesystemservice', (string) $reference);
     }
 
-    public function testThrowIfFileSystemServiceNotSetOnAddConfiguration()
+    public function testThrowIfFileSystemServiceNotSetOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "filesystem_service" at path "flysystem" must be configured.');
@@ -91,7 +91,7 @@ public function testThrowIfFileSystemServiceNotSetOnAddConfiguration()
         $this->processConfigTree($treeBuilder, []);
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedService = 'theService';
 
@@ -113,13 +113,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedService, $config['filesystem_service']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/Factory/Loader/StreamLoaderFactoryTest.php b/Tests/DependencyInjection/Factory/Loader/StreamLoaderFactoryTest.php
index 5699db436..665f224bd 100644
--- a/Tests/DependencyInjection/Factory/Loader/StreamLoaderFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Loader/StreamLoaderFactoryTest.php
@@ -24,28 +24,28 @@
  */
 class StreamLoaderFactoryTest extends TestCase
 {
-    public function testImplementsLoaderFactoryInterface()
+    public function testImplementsLoaderFactoryInterface(): void
     {
         $rc = new \ReflectionClass(StreamLoaderFactory::class);
 
         $this->assertTrue($rc->implementsInterface(LoaderFactoryInterface::class));
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $loader = new StreamLoaderFactory();
 
         $this->assertInstanceOf(StreamLoaderFactory::class, $loader);
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $loader = new StreamLoaderFactory();
 
         $this->assertSame('stream', $loader->getName());
     }
 
-    public function testCreateLoaderDefinitionOnCreate()
+    public function testCreateLoaderDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -66,7 +66,7 @@ public function testCreateLoaderDefinitionOnCreate()
         $this->assertSame('theContext', $loaderDefinition->getArgument(1));
     }
 
-    public function testThrowIfWrapperNotSetOnAddConfiguration()
+    public function testThrowIfWrapperNotSetOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "wrapper" at path "stream" must be configured.');
@@ -82,7 +82,7 @@ public function testThrowIfWrapperNotSetOnAddConfiguration()
         $this->processConfigTree($treeBuilder, []);
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedWrapper = 'theWrapper';
         $expectedContext = 'theContext';
@@ -109,7 +109,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedContext, $config['context']);
     }
 
-    public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
+    public function testAddDefaultOptionsIfNotSetOnAddConfiguration(): void
     {
         $treeBuilder = new TreeBuilder('stream');
         $rootNode = method_exists(TreeBuilder::class, 'getRootNode')
@@ -129,13 +129,7 @@ public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
         $this->assertNull($config['context']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/Factory/Resolver/AwsS3ResolverFactoryTest.php b/Tests/DependencyInjection/Factory/Resolver/AwsS3ResolverFactoryTest.php
index 8c558a507..ed71bb28a 100644
--- a/Tests/DependencyInjection/Factory/Resolver/AwsS3ResolverFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Resolver/AwsS3ResolverFactoryTest.php
@@ -11,6 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\DependencyInjection\Factory\Resolver;
 
+use Aws\S3\S3Client;
 use Liip\ImagineBundle\DependencyInjection\Factory\Resolver\AwsS3ResolverFactory;
 use Liip\ImagineBundle\DependencyInjection\Factory\Resolver\ResolverFactoryInterface;
 use PHPUnit\Framework\TestCase;
@@ -25,28 +26,28 @@
  */
 class AwsS3ResolverFactoryTest extends TestCase
 {
-    public function testImplementsResolverFactoryInterface()
+    public function testImplementsResolverFactoryInterface(): void
     {
         $rc = new \ReflectionClass(AwsS3ResolverFactory::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverFactoryInterface::class));
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $loader = new AwsS3ResolverFactory();
 
         $this->assertInstanceOf(AwsS3ResolverFactory::class, $loader);
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $resolver = new AwsS3ResolverFactory();
 
         $this->assertSame('aws_s3', $resolver->getName());
     }
 
-    public function testCreateResolverDefinitionOnCreate()
+    public function testCreateResolverDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -77,7 +78,7 @@ public function testCreateResolverDefinitionOnCreate()
         $this->assertSame(['barKey' => 'barVal'], $resolverDefinition->getArgument(4));
     }
 
-    public function testCreateS3ClientDefinitionOnCreate()
+    public function testCreateS3ClientDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -96,11 +97,11 @@ public function testCreateS3ClientDefinitionOnCreate()
         $this->assertTrue($container->hasDefinition('liip_imagine.cache.resolver.the_resolver_name.client'));
 
         $clientDefinition = $container->getDefinition('liip_imagine.cache.resolver.the_resolver_name.client');
-        $this->assertSame('Aws\S3\S3Client', $clientDefinition->getClass());
+        $this->assertSame(S3Client::class, $clientDefinition->getClass());
         $this->assertSame(['theClientConfigKey' => 'theClientConfigVal'], $clientDefinition->getArgument(0));
     }
 
-    public function testCreateS3ClientDefinitionWithFactoryOnCreate()
+    public function testCreateS3ClientDefinitionWithFactoryOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -117,10 +118,10 @@ public function testCreateS3ClientDefinitionWithFactoryOnCreate()
         ]);
 
         $clientDefinition = $container->getDefinition('liip_imagine.cache.resolver.the_resolver_name.client');
-        $this->assertSame(['Aws\S3\S3Client', 'factory'], $clientDefinition->getFactory());
+        $this->assertSame([S3Client::class, 'factory'], $clientDefinition->getFactory());
     }
 
-    public function testWrapResolverWithProxyOnCreateWithoutCache()
+    public function testWrapResolverWithProxyOnCreateWithoutCache(): void
     {
         $container = new ContainerBuilder();
 
@@ -154,7 +155,7 @@ public function testWrapResolverWithProxyOnCreateWithoutCache()
         $this->assertSame(['foo'], $resolverDefinition->getArgument(1));
     }
 
-    public function testWrapResolverWithCacheOnCreateWithoutProxy()
+    public function testWrapResolverWithCacheOnCreateWithoutProxy(): void
     {
         $container = new ContainerBuilder();
 
@@ -189,7 +190,7 @@ public function testWrapResolverWithCacheOnCreateWithoutProxy()
         $this->assertSame('liip_imagine.cache.resolver.the_resolver_name.cached', (string) $resolverDefinition->getArgument(1));
     }
 
-    public function testWrapResolverWithProxyAndCacheOnCreate()
+    public function testWrapResolverWithProxyAndCacheOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -232,7 +233,7 @@ public function testWrapResolverWithProxyAndCacheOnCreate()
         $this->assertSame('liip_imagine.cache.resolver.the_resolver_name.cached', (string) $resolverDefinition->getArgument(1));
     }
 
-    public function testWrapResolverWithProxyMatchReplaceStrategyOnCreate()
+    public function testWrapResolverWithProxyMatchReplaceStrategyOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -264,7 +265,7 @@ public function testWrapResolverWithProxyMatchReplaceStrategyOnCreate()
         $this->assertSame(['foo' => 'bar'], $cachedResolverDefinition->getArgument(1));
     }
 
-    public function testSetCachePrefixIfDefined()
+    public function testSetCachePrefixIfDefined(): void
     {
         $container = new ContainerBuilder();
 
@@ -291,7 +292,7 @@ public function testSetCachePrefixIfDefined()
         $this->assertSame(['theCachePrefix'], $methodCalls[0][1]);
     }
 
-    public function testThrowBucketNotSetOnAddConfiguration()
+    public function testThrowBucketNotSetOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "bucket" at path "aws_s3" must be configured.');
@@ -307,7 +308,7 @@ public function testThrowBucketNotSetOnAddConfiguration()
         $this->processConfigTree($treeBuilder, []);
     }
 
-    public function testThrowClientConfigNotSetOnAddConfiguration()
+    public function testThrowClientConfigNotSetOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
         $this->expectExceptionMessage('The child node "client_config" at path "aws_s3" must be configured.');
@@ -327,7 +328,7 @@ public function testThrowClientConfigNotSetOnAddConfiguration()
         ]);
     }
 
-    public function testThrowClientConfigNotArrayOnAddConfiguration()
+    public function testThrowClientConfigNotArrayOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
         $this->expectExceptionMessage('Invalid type for path "aws_s3.client_config". Expected array, but got string');
@@ -348,7 +349,7 @@ public function testThrowClientConfigNotArrayOnAddConfiguration()
         ]);
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedClientConfig = [
             'theKey' => 'theClientConfigVal',
@@ -404,7 +405,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedCachePrefix, $config['cache_prefix']);
     }
 
-    public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
+    public function testAddDefaultOptionsIfNotSetOnAddConfiguration(): void
     {
         $expectedAcl = 'public-read';
 
@@ -433,7 +434,7 @@ public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
         $this->assertNull($config['cache_prefix']);
     }
 
-    public function testSupportAwsV3ClientConfig()
+    public function testSupportAwsV3ClientConfig(): void
     {
         $expectedClientConfig = [
             'credentials' => [
@@ -494,13 +495,7 @@ public function testSupportAwsV3ClientConfig()
         $this->assertSame($expectedCachePrefix, $config['cache_prefix']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/Factory/Resolver/FlysystemResolverFactoryTest.php b/Tests/DependencyInjection/Factory/Resolver/FlysystemResolverFactoryTest.php
index 47fa00acd..1d71ab813 100644
--- a/Tests/DependencyInjection/Factory/Resolver/FlysystemResolverFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Resolver/FlysystemResolverFactoryTest.php
@@ -34,28 +34,28 @@ public function setUp()
         }
     }
 
-    public function testImplementsResolverFactoryInterface()
+    public function testImplementsResolverFactoryInterface(): void
     {
         $rc = new \ReflectionClass(FlysystemResolverFactory::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverFactoryInterface::class));
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $loader = new FlysystemResolverFactory();
 
         $this->assertInstanceOf(FlysystemResolverFactory::class, $loader);
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $resolver = new FlysystemResolverFactory();
 
         $this->assertSame('flysystem', $resolver->getName());
     }
 
-    public function testCreateResolverDefinitionOnCreate()
+    public function testCreateResolverDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -79,7 +79,7 @@ public function testCreateResolverDefinitionOnCreate()
         $this->assertSame('public', $resolverDefinition->getArgument(4));
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedRootUrl = 'http://images.example.com';
         $expectedCachePrefix = 'theCachePrefix';
@@ -116,7 +116,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedVisibility, $config['visibility']);
     }
 
-    public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
+    public function testAddDefaultOptionsIfNotSetOnAddConfiguration(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
 
@@ -133,13 +133,7 @@ public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
         ]);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/Factory/Resolver/WebPathResolverFactoryTest.php b/Tests/DependencyInjection/Factory/Resolver/WebPathResolverFactoryTest.php
index ce966277d..f25391ec3 100644
--- a/Tests/DependencyInjection/Factory/Resolver/WebPathResolverFactoryTest.php
+++ b/Tests/DependencyInjection/Factory/Resolver/WebPathResolverFactoryTest.php
@@ -25,28 +25,28 @@
  */
 class WebPathResolverFactoryTest extends TestCase
 {
-    public function testImplementsResolverFactoryInterface()
+    public function testImplementsResolverFactoryInterface(): void
     {
         $rc = new \ReflectionClass(WebPathResolverFactory::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverFactoryInterface::class));
     }
 
-    public function testCouldBeConstructedWithoutAnyArguments()
+    public function testCouldBeConstructedWithoutAnyArguments(): void
     {
         $loader = new WebPathResolverFactory();
 
         $this->assertInstanceOf(WebPathResolverFactory::class, $loader);
     }
 
-    public function testReturnExpectedName()
+    public function testReturnExpectedName(): void
     {
         $resolver = new WebPathResolverFactory();
 
         $this->assertSame('web_path', $resolver->getName());
     }
 
-    public function testCreateResolverDefinitionOnCreate()
+    public function testCreateResolverDefinitionOnCreate(): void
     {
         $container = new ContainerBuilder();
 
@@ -67,7 +67,7 @@ public function testCreateResolverDefinitionOnCreate()
         $this->assertSame('theCachePrefix', $resolverDefinition->getArgument(3));
     }
 
-    public function testProcessCorrectlyOptionsOnAddConfiguration()
+    public function testProcessCorrectlyOptionsOnAddConfiguration(): void
     {
         $expectedWebPath = 'theWebPath';
         $expectedCachePrefix = 'theCachePrefix';
@@ -94,7 +94,7 @@ public function testProcessCorrectlyOptionsOnAddConfiguration()
         $this->assertSame($expectedCachePrefix, $config['cache_prefix']);
     }
 
-    public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
+    public function testAddDefaultOptionsIfNotSetOnAddConfiguration(): void
     {
         $treeBuilder = new TreeBuilder('web_path');
         $rootNode = method_exists(TreeBuilder::class, 'getRootNode')
@@ -115,13 +115,7 @@ public function testAddDefaultOptionsIfNotSetOnAddConfiguration()
         $this->assertSame('media/cache', $config['cache_prefix']);
     }
 
-    /**
-     * @param TreeBuilder $treeBuilder
-     * @param array       $configs
-     *
-     * @return array
-     */
-    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs)
+    protected function processConfigTree(TreeBuilder $treeBuilder, array $configs): array
     {
         $processor = new Processor();
 
diff --git a/Tests/DependencyInjection/LiipImagineExtensionTest.php b/Tests/DependencyInjection/LiipImagineExtensionTest.php
index 9afceb160..48050268f 100644
--- a/Tests/DependencyInjection/LiipImagineExtensionTest.php
+++ b/Tests/DependencyInjection/LiipImagineExtensionTest.php
@@ -34,7 +34,7 @@ class LiipImagineExtensionTest extends AbstractTest
      */
     protected $containerBuilder;
 
-    public function testUserLoadThrowsExceptionUnlessDriverIsValid()
+    public function testUserLoadThrowsExceptionUnlessDriverIsValid(): void
     {
         $this->expectException(\Symfony\Component\Config\Definition\Exception\InvalidConfigurationException::class);
 
@@ -42,7 +42,7 @@ public function testUserLoadThrowsExceptionUnlessDriverIsValid()
         $loader->load([['driver' => 'foo']], new ContainerBuilder());
     }
 
-    public function testLoadFilterSetsDefaults()
+    public function testLoadFilterSetsDefaults(): void
     {
         $this->createConfigurationWithOneEmptyFilterSet();
         $filterSets = $this->containerBuilder->getParameter('liip_imagine.filter_sets');
@@ -63,7 +63,7 @@ public function testLoadFilterSetsDefaults()
         $this->assertNull($emptyFilterSet['default_image']);
     }
 
-    public function testLoadFilterSetsWithDefaults()
+    public function testLoadFilterSetsWithDefaults(): void
     {
         $this->createConfigurationWithDefaultsFilterSets();
         $filterSets = $this->containerBuilder->getParameter('liip_imagine.filter_sets');
@@ -111,64 +111,7 @@ public function testLoadFilterSetsWithDefaults()
         $this->assertArrayHasKey('mozjpeg', $filterSet2['post_processors']);
     }
 
-    protected function createConfigurationWithDefaultsFilterSets()
-    {
-        if (!class_exists(Parser::class)) {
-            $this->markTestSkipped('Requires the symfony/yaml package.');
-        }
-
-        $this->createConfiguration($this->getConfigurationWithDefaultsFilterSets());
-    }
-
-    protected function createConfigurationWithOneEmptyFilterSet()
-    {
-        if (!class_exists(Parser::class)) {
-            $this->markTestSkipped('Requires the symfony/yaml package.');
-        }
-
-        $this->createConfiguration($this->getConfigurationWithOneEmptyFilterSet());
-    }
-
-    protected function getConfigurationWithOneEmptyFilterSet()
-    {
-        $yaml = <<<'EOF'
-filter_sets:
-    empty_filter_set: ~
-EOF;
-        $parser = new Parser();
-
-        return $parser->parse($yaml);
-    }
-
-    protected function getConfigurationWithDefaultsFilterSets()
-    {
-        $yaml = <<<'EOF'
-default_filter_set_settings:
-    jpeg_quality: 70
-    quality: 80
-    data_loader: 'my_loader'
-    filters:
-        thumbnail: { mode: 'inset' }
-    post_processors:
-        mozjpeg: {}
-filter_sets:
-    filter_set_1:
-        jpeg_quality: 80
-        quality: 90
-        data_loader: 'my_new_loader'
-        filters:
-            thumbnail: { size: [483, 350], mode: 'outbound' }
-    filter_set_2:
-        filters:
-            thumbnail: { size: [483, 350] }
-            fixed: { width: 120, height: 90 }
-EOF;
-        $parser = new Parser();
-
-        return $parser->parse($yaml);
-    }
-
-    public function testLoadWithDefaults()
+    public function testLoadWithDefaults(): void
     {
         $this->createEmptyConfiguration();
 
@@ -186,7 +129,7 @@ public function testLoadWithDefaults()
         );
     }
 
-    public function testTemplatingFilterExtensionIsDeprecated()
+    public function testTemplatingFilterExtensionIsDeprecated(): void
     {
         $this->createEmptyConfiguration();
 
@@ -194,7 +137,7 @@ public function testTemplatingFilterExtensionIsDeprecated()
         $this->assertDefinitionIsDeprecated('liip_imagine.templating.filter_helper', 'The "liip_imagine.templating.filter_helper" service is deprecated since LiipImagineBundle 2.2 and will be removed in 3.0.');
     }
 
-    public static function provideFactoryData()
+    public static function provideFactoryData(): array
     {
         return [
             [
@@ -214,7 +157,7 @@ public static function provideFactoryData()
      * @param string $service
      * @param string $factory
      */
-    public function testFactoriesConfiguration($service, $factory)
+    public function testFactoriesConfiguration($service, $factory): void
     {
         $this->createEmptyConfiguration();
         $definition = $this->containerBuilder->getDefinition($service);
@@ -222,21 +165,11 @@ public function testFactoriesConfiguration($service, $factory)
         $this->assertSame($factory, $definition->getFactory());
     }
 
-    protected function createEmptyConfiguration(): void
-    {
-        $this->createConfiguration([]);
-    }
-
-    protected function createFullConfiguration(): void
-    {
-        $this->createConfiguration($this->getFullConfig());
-    }
-
     /**
      * @group legacy
      * @expectedDeprecation Symfony templating integration has been deprecated since LiipImagineBundle 2.2 and will be removed in 3.0. Use Twig and use "false" as "liip_imagine.templating" value instead.
      */
-    public function testHelperIsRegisteredWhenTemplatingIsEnabled()
+    public function testHelperIsRegisteredWhenTemplatingIsEnabled(): void
     {
         $this->createConfiguration([
             'templating' => true,
@@ -244,7 +177,7 @@ public function testHelperIsRegisteredWhenTemplatingIsEnabled()
         $this->assertHasDefinition('liip_imagine.templating.filter_helper');
     }
 
-    public function testHelperIsNotRegisteredWhenTemplatingIsDisabled()
+    public function testHelperIsNotRegisteredWhenTemplatingIsDisabled(): void
     {
         $this->createConfiguration([
             'templating' => false,
@@ -252,6 +185,73 @@ public function testHelperIsNotRegisteredWhenTemplatingIsDisabled()
         $this->assertHasNotDefinition('liip_imagine.templating.filter_helper');
     }
 
+    protected function createConfigurationWithDefaultsFilterSets(): void
+    {
+        if (!class_exists(Parser::class)) {
+            $this->markTestSkipped('Requires the symfony/yaml package.');
+        }
+
+        $this->createConfiguration($this->getConfigurationWithDefaultsFilterSets());
+    }
+
+    protected function createConfigurationWithOneEmptyFilterSet(): void
+    {
+        if (!class_exists(Parser::class)) {
+            $this->markTestSkipped('Requires the symfony/yaml package.');
+        }
+
+        $this->createConfiguration($this->getConfigurationWithOneEmptyFilterSet());
+    }
+
+    protected function getConfigurationWithOneEmptyFilterSet()
+    {
+        $yaml = <<<'EOF'
+filter_sets:
+    empty_filter_set: ~
+EOF;
+        $parser = new Parser();
+
+        return $parser->parse($yaml);
+    }
+
+    protected function getConfigurationWithDefaultsFilterSets()
+    {
+        $yaml = <<<'EOF'
+default_filter_set_settings:
+    jpeg_quality: 70
+    quality: 80
+    data_loader: 'my_loader'
+    filters:
+        thumbnail: { mode: 'inset' }
+    post_processors:
+        mozjpeg: {}
+filter_sets:
+    filter_set_1:
+        jpeg_quality: 80
+        quality: 90
+        data_loader: 'my_new_loader'
+        filters:
+            thumbnail: { size: [483, 350], mode: 'outbound' }
+    filter_set_2:
+        filters:
+            thumbnail: { size: [483, 350] }
+            fixed: { width: 120, height: 90 }
+EOF;
+        $parser = new Parser();
+
+        return $parser->parse($yaml);
+    }
+
+    protected function createEmptyConfiguration(): void
+    {
+        $this->createConfiguration([]);
+    }
+
+    protected function createFullConfiguration(): void
+    {
+        $this->createConfiguration($this->getFullConfig());
+    }
+
     protected function createConfiguration(array $configuration): void
     {
         $this->containerBuilder = new ContainerBuilder();
@@ -301,45 +301,27 @@ protected function getFullConfig()
         return $parser->parse($yaml);
     }
 
-    /**
-     * @param string $value
-     * @param string $key
-     */
-    private function assertAlias($value, $key)
+    private function assertAlias(string $value, string $key): void
     {
         $this->assertSame($value, (string) $this->containerBuilder->getAlias($key), sprintf('%s alias is correct', $key));
     }
 
-    /**
-     * @param string $value
-     * @param string $key
-     */
-    private function assertParameter($value, $key)
+    private function assertParameter(string $value, string $key): void
     {
         $this->assertSame($value, $this->containerBuilder->getParameter($key), sprintf('%s parameter is correct', $key));
     }
 
-    /**
-     * @param string $id
-     */
-    private function assertHasDefinition($id)
+    private function assertHasDefinition(string $id): void
     {
         $this->assertTrue(($this->containerBuilder->hasDefinition($id) ?: $this->containerBuilder->hasAlias($id)));
     }
 
-    /**
-     * @param string $id
-     */
-    private function assertHasNotDefinition($id)
+    private function assertHasNotDefinition(string $id): void
     {
         $this->assertFalse(($this->containerBuilder->hasDefinition($id) || $this->containerBuilder->hasAlias($id)));
     }
 
-    /**
-     * @param Definition $definition
-     * @param array      $arguments
-     */
-    private function assertDICConstructorArguments(Definition $definition, array $arguments)
+    private function assertDICConstructorArguments(Definition $definition, array $arguments): void
     {
         $castArrayElementsToString = function (array $a): array {
             return array_map(function ($v) { return (string) $v; }, $a);
@@ -358,7 +340,7 @@ private function assertDICConstructorArguments(Definition $definition, array $ar
         ]));
     }
 
-    private function assertDefinitionIsDeprecated(string $id, string $message)
+    private function assertDefinitionIsDeprecated(string $id, string $message): void
     {
         $definition = $this->containerBuilder->getDefinition($id);
 
diff --git a/Tests/Events/CacheResolveEventTest.php b/Tests/Events/CacheResolveEventTest.php
index 2d56ddc6d..7ef9f9e5d 100644
--- a/Tests/Events/CacheResolveEventTest.php
+++ b/Tests/Events/CacheResolveEventTest.php
@@ -23,29 +23,29 @@ protected function setUp()
     {
     }
 
-    public function testShouldAllowSetPathInConstruct()
+    public function testShouldAllowSetPathInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
 
-        $this->assertAttributeSame('default_path', 'path', $event);
+        $this->assertSame('default_path', $event->getPath());
     }
 
-    public function testShouldAllowSetPathByMethod()
+    public function testShouldAllowSetPathByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setPath('new_path');
 
-        $this->assertAttributeSame('new_path', 'path', $event);
+        $this->assertSame('new_path', $event->getPath());
     }
 
-    public function testShouldAllowGetPathWhichWasSetInConstruct()
+    public function testShouldAllowGetPathWhichWasSetInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
 
         $this->assertSame('default_path', $event->getPath());
     }
 
-    public function testShouldAllowGetPathWhichWasSetByMethod()
+    public function testShouldAllowGetPathWhichWasSetByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setPath('new_path');
@@ -53,29 +53,29 @@ public function testShouldAllowGetPathWhichWasSetByMethod()
         $this->assertSame('new_path', $event->getPath());
     }
 
-    public function testShouldAllowSetFilterInConstruct()
+    public function testShouldAllowSetFilterInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
 
-        $this->assertAttributeSame('default_filter', 'filter', $event);
+        $this->assertSame('default_filter', $event->getFilter());
     }
 
-    public function testShouldAllowSetFilterByMethod()
+    public function testShouldAllowSetFilterByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setFilter('new_filter');
 
-        $this->assertAttributeSame('new_filter', 'filter', $event);
+        $this->assertSame('new_filter', $event->getFilter());
     }
 
-    public function testShouldAllowGetFilterWhichWasSetInConstruct()
+    public function testShouldAllowGetFilterWhichWasSetInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
 
         $this->assertSame('default_filter', $event->getFilter());
     }
 
-    public function testShouldAllowGetFilterWhichWasSetByMethod()
+    public function testShouldAllowGetFilterWhichWasSetByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setFilter('new_filter');
@@ -83,29 +83,29 @@ public function testShouldAllowGetFilterWhichWasSetByMethod()
         $this->assertSame('new_filter', $event->getFilter());
     }
 
-    public function testShouldAllowSetUrlInConstruct()
+    public function testShouldAllowSetUrlInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter', 'default_url');
 
-        $this->assertAttributeSame('default_url', 'url', $event);
+        $this->assertSame('default_url', $event->getUrl());
     }
 
-    public function testShouldAllowSetUrlByMethod()
+    public function testShouldAllowSetUrlByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setUrl('new_url');
 
-        $this->assertAttributeSame('new_url', 'url', $event);
+        $this->assertSame('new_url', $event->getUrl());
     }
 
-    public function testShouldAllowGetUrlWhichWasSetInConstruct()
+    public function testShouldAllowGetUrlWhichWasSetInConstruct(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter', 'default_url');
 
         $this->assertSame('default_url', $event->getUrl());
     }
 
-    public function testShouldAllowGetUrlWhichWasSetByMethod()
+    public function testShouldAllowGetUrlWhichWasSetByMethod(): void
     {
         $event = new CacheResolveEvent('default_path', 'default_filter');
         $event->setUrl('new_url');
diff --git a/Tests/Exception/Imagine/Cache/Resolver/NotResolvableExceptionTest.php b/Tests/Exception/Imagine/Cache/Resolver/NotResolvableExceptionTest.php
index ae73c83fa..4d85d56ba 100644
--- a/Tests/Exception/Imagine/Cache/Resolver/NotResolvableExceptionTest.php
+++ b/Tests/Exception/Imagine/Cache/Resolver/NotResolvableExceptionTest.php
@@ -20,14 +20,14 @@
  */
 class NotResolvableExceptionTest extends TestCase
 {
-    public function testSubClassOfRuntimeException()
+    public function testSubClassOfRuntimeException(): void
     {
         $e = new NotResolvableException();
 
         $this->assertInstanceOf(\RuntimeException::class, $e);
     }
 
-    public function testImplementsExceptionInterface()
+    public function testImplementsExceptionInterface(): void
     {
         $e = new NotResolvableException();
 
diff --git a/Tests/Exception/Imagine/Cache/Resolver/NotStorableExceptionTest.php b/Tests/Exception/Imagine/Cache/Resolver/NotStorableExceptionTest.php
index 8fee76bce..84f7214d9 100644
--- a/Tests/Exception/Imagine/Cache/Resolver/NotStorableExceptionTest.php
+++ b/Tests/Exception/Imagine/Cache/Resolver/NotStorableExceptionTest.php
@@ -20,14 +20,14 @@
  */
 class NotStorableExceptionTest extends TestCase
 {
-    public function testSubClassOfRuntimeException()
+    public function testSubClassOfRuntimeException(): void
     {
         $e = new NotStorableException();
 
         $this->assertInstanceOf(\RuntimeException::class, $e);
     }
 
-    public function testImplementsExceptionInterface()
+    public function testImplementsExceptionInterface(): void
     {
         $e = new NotStorableException();
 
diff --git a/Tests/Exception/Imagine/Filter/PostProcessor/InvalidOptionExceptionTest.php b/Tests/Exception/Imagine/Filter/PostProcessor/InvalidOptionExceptionTest.php
index 1678f8025..ef9f8f512 100644
--- a/Tests/Exception/Imagine/Filter/PostProcessor/InvalidOptionExceptionTest.php
+++ b/Tests/Exception/Imagine/Filter/PostProcessor/InvalidOptionExceptionTest.php
@@ -12,7 +12,7 @@
 namespace Liip\ImagineBundle\Tests\Exception\Imagine\Filter\PostProcessor;
 
 use Liip\ImagineBundle\Exception\Imagine\Filter\PostProcessor\InvalidOptionException;
-use Symfony\Bundle\FrameworkBundle\Tests\TestCase;
+use PHPUnit\Framework\TestCase;
 
 /**
  * @covers \Liip\ImagineBundle\Exception\Imagine\Filter\PostProcessor\InvalidOptionException
@@ -38,7 +38,7 @@ public function testExceptionMessage(string $message, array $options, string $op
     {
         $exception = new InvalidOptionException($message, $options);
 
-        $this->assertContains(sprintf('(%s)', $message), $exception->getMessage());
-        $this->assertContains(sprintf('[%s]', $optionsText), $exception->getMessage());
+        $this->assertStringContainsString(sprintf('(%s)', $message), $exception->getMessage());
+        $this->assertStringContainsString(sprintf('[%s]', $optionsText), $exception->getMessage());
     }
 }
diff --git a/Tests/Fixtures/Model.php b/Tests/Fixtures/Model.php
index 724eeaf70..030ef94d1 100644
--- a/Tests/Fixtures/Model.php
+++ b/Tests/Fixtures/Model.php
@@ -13,7 +13,7 @@
 
 class Model
 {
-    public function get($key)
+    public function get($key): void
     {
     }
 }
diff --git a/Tests/Form/Type/ImageTypeTest.php b/Tests/Form/Type/ImageTypeTest.php
index eb9576a28..5657c3156 100644
--- a/Tests/Form/Type/ImageTypeTest.php
+++ b/Tests/Form/Type/ImageTypeTest.php
@@ -31,14 +31,14 @@ protected function setUp()
         }
     }
 
-    public function testGetParent()
+    public function testGetParent(): void
     {
         $type = new ImageType();
 
         $this->assertSame(FileType::class, $type->getParent());
     }
 
-    public function testConfigureOptions()
+    public function testConfigureOptions(): void
     {
         $resolver = new OptionsResolver();
         $type = new ImageType();
@@ -54,7 +54,7 @@ public function testConfigureOptions()
         $this->assertTrue($resolver->isDefined('link_attr'));
     }
 
-    public function testBuildView()
+    public function testBuildView(): void
     {
         $options = [
             'image_path' => 'foo',
diff --git a/Tests/Functional/AbstractSetupWebTestCase.php b/Tests/Functional/AbstractSetupWebTestCase.php
index 449ad36ef..dfbe6efd7 100644
--- a/Tests/Functional/AbstractSetupWebTestCase.php
+++ b/Tests/Functional/AbstractSetupWebTestCase.php
@@ -11,7 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\Functional;
 
-use Symfony\Bundle\FrameworkBundle\Client;
+use Symfony\Bundle\FrameworkBundle\KernelBrowser;
 use Symfony\Component\Filesystem\Filesystem;
 
 /**
@@ -20,7 +20,7 @@
 class AbstractSetupWebTestCase extends AbstractWebTestCase
 {
     /**
-     * @var Client
+     * @var KernelBrowser
      */
     protected $client;
 
diff --git a/Tests/Functional/AbstractWebTestCase.php b/Tests/Functional/AbstractWebTestCase.php
index 1627e25c4..43be920d9 100644
--- a/Tests/Functional/AbstractWebTestCase.php
+++ b/Tests/Functional/AbstractWebTestCase.php
@@ -11,6 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\Functional;
 
+use Liip\ImagineBundle\Tests\Functional\app\AppKernel;
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 use Symfony\Component\BrowserKit\Client;
 
@@ -35,36 +36,31 @@ public static function getKernelClass()
     {
         require_once __DIR__.'/app/AppKernel.php';
 
-        return 'Liip\ImagineBundle\Tests\Functional\app\AppKernel';
+        return AppKernel::class;
     }
 
     /**
-     * @param string $name
-     *
      * @return object
      */
-    protected function getService($name)
+    protected function getService(string $name)
     {
         return static::$kernel->getContainer()->get($name);
     }
 
     /**
-     * @param string $name
-     *
      * @return mixed
      */
-    protected function getParameter($name)
+    protected function getParameter(string $name)
     {
         return static::$kernel->getContainer()->getParameter($name);
     }
 
     /**
      * @param object $object
-     * @param string $name
      *
      * @return mixed
      */
-    protected function getPrivateProperty($object, $name)
+    protected function getPrivateProperty($object, string $name)
     {
         $r = new \ReflectionObject($object);
 
diff --git a/Tests/Functional/Binary/Loader/ChainLoaderTest.php b/Tests/Functional/Binary/Loader/ChainLoaderTest.php
index 914503e66..370aacc0d 100644
--- a/Tests/Functional/Binary/Loader/ChainLoaderTest.php
+++ b/Tests/Functional/Binary/Loader/ChainLoaderTest.php
@@ -31,8 +31,6 @@ public function testFind(): void
     }
 
     /**
-     * @param string $name
-     *
      * @return ChainLoader|object
      */
     private function getLoader(string $name): ChainLoader
diff --git a/Tests/Functional/Binary/Loader/FileSystemLoaderTest.php b/Tests/Functional/Binary/Loader/FileSystemLoaderTest.php
index d133ccd72..e068fb498 100644
--- a/Tests/Functional/Binary/Loader/FileSystemLoaderTest.php
+++ b/Tests/Functional/Binary/Loader/FileSystemLoaderTest.php
@@ -19,7 +19,7 @@
  */
 class FileSystemLoaderTest extends AbstractWebTestCase
 {
-    public function testMultipleLoadersHaveDifferentLocatorInstances()
+    public function testMultipleLoadersHaveDifferentLocatorInstances(): void
     {
         static::createClient();
 
@@ -41,11 +41,9 @@ public function testMultipleLoadersHaveDifferentLocatorInstances()
     }
 
     /**
-     * @param string $name
-     *
      * @return FileSystemLoader|object
      */
-    private function getLoader($name)
+    private function getLoader(string $name)
     {
         return $this->getService(sprintf('liip_imagine.binary.loader.%s', $name));
     }
diff --git a/Tests/Functional/Binary/Locator/FileSystemLocatorTest.php b/Tests/Functional/Binary/Locator/FileSystemLocatorTest.php
index 00483f1cb..e411537ca 100644
--- a/Tests/Functional/Binary/Locator/FileSystemLocatorTest.php
+++ b/Tests/Functional/Binary/Locator/FileSystemLocatorTest.php
@@ -20,7 +20,7 @@
  */
 class FileSystemLocatorTest extends AbstractWebTestCase
 {
-    public function testBundleResourcesOnAllLoader()
+    public function testBundleResourcesOnAllLoader(): void
     {
         static::createClient();
 
@@ -35,7 +35,7 @@ public function testBundleResourcesOnAllLoader()
         $this->assertBarBundleResourcesExist($locator);
     }
 
-    public function testBundleResourcesOnFooLoader()
+    public function testBundleResourcesOnFooLoader(): void
     {
         static::createClient();
 
@@ -48,7 +48,7 @@ public function testBundleResourcesOnFooLoader()
         $this->assertFooBundleResourcesExist($locator);
     }
 
-    public function testBundleResourcesOnBarLoader()
+    public function testBundleResourcesOnBarLoader(): void
     {
         static::createClient();
 
@@ -61,20 +61,12 @@ public function testBundleResourcesOnBarLoader()
         $this->assertBarBundleResourcesExist($locator, true);
     }
 
-    /**
-     * @param string $name
-     *
-     * @return FileSystemLocator
-     */
-    private function getFileSystemLoaderLocator($name)
+    private function getFileSystemLoaderLocator(string $name): FileSystemLocator
     {
         return $this->getPrivateProperty($this->getService(sprintf('liip_imagine.binary.loader.%s', $name)), 'locator');
     }
 
-    /**
-     * @param LocatorInterface $locator
-     */
-    private function assertFooBundleResourcesExist(LocatorInterface $locator)
+    private function assertFooBundleResourcesExist(LocatorInterface $locator): void
     {
         $this->assertLocatedFileContentsStartsWith($locator, 'file.ext', 'Fixtures/FooBundle');
         $this->assertLocatedFileContentsStartsWith($locator, '@LiipFooBundle:file.ext', 'Fixtures/FooBundle');
@@ -82,11 +74,7 @@ private function assertFooBundleResourcesExist(LocatorInterface $locator)
         $this->assertLocatedFileContentsStartsWith($locator, '@LiipFooBundle:foo-bundle-file.ext', 'Fixtures/FooBundle');
     }
 
-    /**
-     * @param LocatorInterface $locator
-     * @param bool             $only
-     */
-    private function assertBarBundleResourcesExist(LocatorInterface $locator, $only = false)
+    private function assertBarBundleResourcesExist(LocatorInterface $locator, bool $only = false): void
     {
         $this->assertLocatedFileContentsStartsWith($locator, 'file.ext', $only ? 'Fixtures/BarBundle' : 'Fixtures/FooBundle');
         $this->assertLocatedFileContentsStartsWith($locator, '@LiipBarBundle:file.ext', 'Fixtures/BarBundle');
@@ -94,13 +82,7 @@ private function assertBarBundleResourcesExist(LocatorInterface $locator, $only
         $this->assertLocatedFileContentsStartsWith($locator, '@LiipBarBundle:bar-bundle-file.ext', 'Fixtures/BarBundle');
     }
 
-    /**
-     * @param LocatorInterface $locator
-     * @param string           $filePath
-     * @param string           $expectedContents
-     * @param string|null      $message
-     */
-    private function assertLocatedFileContentsStartsWith(LocatorInterface $locator, $filePath, $expectedContents, $message = '')
+    private function assertLocatedFileContentsStartsWith(LocatorInterface $locator, string $filePath, string $expectedContents, $message = ''): void
     {
         $this->assertStringStartsWith($expectedContents, file_get_contents($locator->locate($filePath)), $message);
     }
diff --git a/Tests/Functional/Command/AbstractCommandTestCase.php b/Tests/Functional/Command/AbstractCommandTestCase.php
index 10da012d6..f99d42832 100644
--- a/Tests/Functional/Command/AbstractCommandTestCase.php
+++ b/Tests/Functional/Command/AbstractCommandTestCase.php
@@ -22,7 +22,8 @@ class AbstractCommandTestCase extends AbstractSetupWebTestCase
 {
     protected function executeConsole(string $commandName, array $arguments = [], &$return = null): string
     {
-        $application = new Application($this->createClient()->getKernel());
+        $kernel = static::createKernel();
+        $application = new Application($kernel);
         $command = $application->find($commandName);
 
         $arguments = array_replace(['command' => $command->getName()], $arguments);
@@ -81,7 +82,7 @@ protected function assertOutputContainsFailedImages($output, array $images, arra
     {
         foreach ($images as $i) {
             foreach ($filters as $f) {
-                $this->assertContains(sprintf('%s[%s] (failed)', $i, $f), $output);
+                $this->assertStringContainsString(sprintf('%s[%s] (failed)', $i, $f), $output);
             }
         }
     }
@@ -95,7 +96,7 @@ protected function assertOutputContainsImage($output, $image, $filter, $type): v
             $filter,
             $image,
         ]);
-        $this->assertContains($expected, $output);
+        $this->assertStringContainsString($expected, $output);
     }
 
     /**
diff --git a/Tests/Functional/Command/RemoveCacheCommandTest.php b/Tests/Functional/Command/RemoveCacheCommandTest.php
index 6a283a55c..3953bb114 100644
--- a/Tests/Functional/Command/RemoveCacheCommandTest.php
+++ b/Tests/Functional/Command/RemoveCacheCommandTest.php
@@ -146,7 +146,7 @@ protected function assertOutputContainsSkippedImages($output, array $images, arr
     {
         foreach ($images as $i) {
             foreach ($filters as $f) {
-                $this->assertContains(sprintf('%s[%s] (skipped)', $i, $f), $output);
+                $this->assertStringContainsString(sprintf('%s[%s] (skipped)', $i, $f), $output);
             }
         }
     }
@@ -155,7 +155,7 @@ protected function assertOutputContainsRemovedImages($output, array $images, arr
     {
         foreach ($images as $i) {
             foreach ($filters as $f) {
-                $this->assertContains(sprintf('%s[%s] (removed)', $i, $f), $output);
+                $this->assertStringContainsString(sprintf('%s[%s] (removed)', $i, $f), $output);
             }
         }
     }
@@ -166,11 +166,11 @@ protected function assertOutputContainsRemovedImages($output, array $images, arr
      */
     protected function assertOutputContainsSummary(string $output, array $images, array $filters, int $failures = 0): void
     {
-        $this->assertContains(sprintf('Completed %d removal', (count($images) * count($filters)) - $failures), $output);
-        $this->assertContains(sprintf('%d image', count($images)), $output);
-        $this->assertContains(sprintf('%d filter', count($filters)), $output);
+        $this->assertStringContainsString(sprintf('Completed %d removal', (\count($images) * \count($filters)) - $failures), $output);
+        $this->assertStringContainsString(sprintf('%d image', \count($images)), $output);
+        $this->assertStringContainsString(sprintf('%d filter', \count($filters)), $output);
         if (0 !== $failures) {
-            $this->assertContains(sprintf('%d failure', $failures), $output);
+            $this->assertStringContainsString(sprintf('%d failure', $failures), $output);
         }
     }
 
@@ -180,11 +180,11 @@ protected function assertOutputContainsSummary(string $output, array $images, ar
      */
     protected function assertOutputNotContainsSummary(string $output, array $images, array $filters, int $failures = 0): void
     {
-        $this->assertNotContains(sprintf('Completed %d removal', (count($images) * count($filters)) - $failures), $output);
-        $this->assertNotContains(sprintf('%d image', count($images)), $output);
-        $this->assertNotContains(sprintf('%d filter', count($filters)), $output);
+        $this->assertStringNotContainsString(sprintf('Completed %d removal', (\count($images) * \count($filters)) - $failures), $output);
+        $this->assertStringNotContainsString(sprintf('%d image', \count($images)), $output);
+        $this->assertStringNotContainsString(sprintf('%d filter', \count($filters)), $output);
         if (0 !== $failures) {
-            $this->assertNotContains(sprintf('%d failure', $failures), $output);
+            $this->assertStringNotContainsString(sprintf('%d failure', $failures), $output);
         }
     }
 
@@ -197,7 +197,7 @@ private function executeRemoveCacheCommand(array $paths, array $filters = [], ar
     {
         $options = array_merge(['path' => $paths], $additionalOptions);
 
-        if (0 < count($filters)) {
+        if (0 < \count($filters)) {
             $options['--filter'] = $filters;
         }
 
diff --git a/Tests/Functional/Command/ResolveCacheCommandTest.php b/Tests/Functional/Command/ResolveCacheCommandTest.php
index 26f0c6d6a..96e96aeb7 100644
--- a/Tests/Functional/Command/ResolveCacheCommandTest.php
+++ b/Tests/Functional/Command/ResolveCacheCommandTest.php
@@ -172,14 +172,14 @@ public function testScriptReadableOption(): void
 
         $output = $this->executeResolveCacheCommand($images, $filters, ['--as-script' => false]);
 
-        $this->assertContains('liip/imagine-bundle', $output);
+        $this->assertStringContainsString('liip/imagine-bundle', $output);
         $this->assertOutputContainsFailedImages($output, $images, $filters);
         $this->assertOutputContainsSummary($output, $images, $filters, 2);
 
         $output = $this->executeResolveCacheCommand($images, $filters, ['--as-script' => true]);
 
         $this->assertImagesNotExist($images, $filters);
-        $this->assertNotContains('liip/imagine-bundle', $output);
+        $this->assertStringNotContainsString('liip/imagine-bundle', $output);
         $this->assertOutputContainsFailedImages($output, $images, $filters);
         $this->assertOutputNotContainsSummary($output, $images, $filters, 2);
 
@@ -192,11 +192,11 @@ public function testScriptReadableOption(): void
      */
     protected function assertOutputContainsSummary(string $output, array $images, array $filters, int $failures = 0): void
     {
-        $this->assertContains(sprintf('Completed %d resolution', (count($images) * count($filters)) - $failures), $output);
-        $this->assertContains(sprintf('%d image', count($images)), $output);
-        $this->assertContains(sprintf('%d filter', count($filters)), $output);
+        $this->assertStringContainsString(sprintf('Completed %d resolution', (\count($images) * \count($filters)) - $failures), $output);
+        $this->assertStringContainsString(sprintf('%d image', \count($images)), $output);
+        $this->assertStringContainsString(sprintf('%d filter', \count($filters)), $output);
         if (0 !== $failures) {
-            $this->assertContains(sprintf('%d failure', $failures), $output);
+            $this->assertStringContainsString(sprintf('%d failure', $failures), $output);
         }
     }
 
@@ -206,11 +206,11 @@ protected function assertOutputContainsSummary(string $output, array $images, ar
      */
     protected function assertOutputNotContainsSummary(string $output, array $images, array $filters, int $failures = 0): void
     {
-        $this->assertNotContains(sprintf('Completed %d resolution', (count($images) * count($filters)) - $failures), $output);
-        $this->assertNotContains(sprintf('%d image', count($images)), $output);
-        $this->assertNotContains(sprintf('%d filter', count($filters)), $output);
+        $this->assertStringNotContainsString(sprintf('Completed %d resolution', (\count($images) * \count($filters)) - $failures), $output);
+        $this->assertStringNotContainsString(sprintf('%d image', \count($images)), $output);
+        $this->assertStringNotContainsString(sprintf('%d filter', \count($filters)), $output);
         if (0 !== $failures) {
-            $this->assertNotContains(sprintf('%d failure', $failures), $output);
+            $this->assertStringNotContainsString(sprintf('%d failure', $failures), $output);
         }
     }
 
@@ -218,15 +218,12 @@ protected function assertOutputNotContainsSummary(string $output, array $images,
      * @param string[] $paths
      * @param string[] $filters
      * @param string[] $additionalOptions
-     * @param int      $return
-     *
-     * @return string
      */
-    private function executeResolveCacheCommand(array $paths, array $filters = [], array $additionalOptions = [], &$return = null): string
+    private function executeResolveCacheCommand(array $paths, array $filters = [], array $additionalOptions = [], int &$return = null): string
     {
         $options = array_merge(['path' => $paths], $additionalOptions);
 
-        if (0 < count($filters)) {
+        if (0 < \count($filters)) {
             $options['--filter'] = $filters;
         }
 
diff --git a/Tests/Functional/Controller/ImagineControllerTest.php b/Tests/Functional/Controller/ImagineControllerTest.php
index faa3a5ae6..af4d2c8c5 100644
--- a/Tests/Functional/Controller/ImagineControllerTest.php
+++ b/Tests/Functional/Controller/ImagineControllerTest.php
@@ -21,12 +21,12 @@
  */
 class ImagineControllerTest extends AbstractSetupWebTestCase
 {
-    public function testCouldBeGetFromContainer()
+    public function testCouldBeGetFromContainer(): void
     {
         $this->assertInstanceOf(ImagineController::class, self::$kernel->getContainer()->get(ImagineController::class));
     }
 
-    public function testShouldResolvePopulatingCacheFirst()
+    public function testShouldResolvePopulatingCacheFirst(): void
     {
         //guard
         $this->assertFileNotExists($this->cacheRoot.'/thumbnail_web_path/images/cats.jpeg');
@@ -42,7 +42,7 @@ public function testShouldResolvePopulatingCacheFirst()
         $this->assertFileExists($this->cacheRoot.'/thumbnail_web_path/images/cats.jpeg');
     }
 
-    public function testShouldResolveFromCache()
+    public function testShouldResolveFromCache(): void
     {
         $this->filesystem->dumpFile(
             $this->cacheRoot.'/thumbnail_web_path/images/cats.jpeg',
@@ -60,7 +60,7 @@ public function testShouldResolveFromCache()
         $this->assertFileExists($this->cacheRoot.'/thumbnail_web_path/images/cats.jpeg');
     }
 
-    public function testThrowBadRequestIfSignInvalidWhileUsingCustomFilters()
+    public function testThrowBadRequestIfSignInvalidWhileUsingCustomFilters(): void
     {
         $this->expectException(\Symfony\Component\HttpKernel\Exception\BadRequestHttpException::class);
         $this->expectExceptionMessage('Signed url does not pass the sign check for path "images/cats.jpeg" and filter "thumbnail_web_path" and runtime config {"thumbnail":{"size":["50","50"]}}');
@@ -73,7 +73,7 @@ public function testThrowBadRequestIfSignInvalidWhileUsingCustomFilters()
         ]));
     }
 
-    public function testShouldThrowNotFoundHttpExceptionIfFiltersNotArray()
+    public function testShouldThrowNotFoundHttpExceptionIfFiltersNotArray(): void
     {
         $this->expectException(\Symfony\Component\HttpKernel\Exception\NotFoundHttpException::class);
         $this->expectExceptionMessage('Filters must be an array. Value was "some-string"');
@@ -84,7 +84,7 @@ public function testShouldThrowNotFoundHttpExceptionIfFiltersNotArray()
         ]));
     }
 
-    public function testShouldThrowNotFoundHttpExceptionIfFileNotExists()
+    public function testShouldThrowNotFoundHttpExceptionIfFileNotExists(): void
     {
         $this->expectException(\Symfony\Component\HttpKernel\Exception\NotFoundHttpException::class);
         $this->expectExceptionMessage('Source image for path "images/shrodinger_cats_which_not_exist.jpeg" could not be found');
@@ -92,14 +92,14 @@ public function testShouldThrowNotFoundHttpExceptionIfFileNotExists()
         $this->client->request('GET', '/media/cache/resolve/thumbnail_web_path/images/shrodinger_cats_which_not_exist.jpeg');
     }
 
-    public function testInvalidFilterShouldThrowNotFoundHttpException()
+    public function testInvalidFilterShouldThrowNotFoundHttpException(): void
     {
         $this->expectException(\Symfony\Component\HttpKernel\Exception\NotFoundHttpException::class);
 
         $this->client->request('GET', '/media/cache/resolve/invalid-filter/images/cats.jpeg');
     }
 
-    public function testShouldResolveWithCustomFiltersPopulatingCacheFirst()
+    public function testShouldResolveWithCustomFiltersPopulatingCacheFirst(): void
     {
         /** @var Signer $signer */
         $signer = self::$kernel->getContainer()->get('liip_imagine.cache.signer');
@@ -132,7 +132,7 @@ public function testShouldResolveWithCustomFiltersPopulatingCacheFirst()
         $this->assertFileExists($this->cacheRoot.'/'.$expectedCachePath);
     }
 
-    public function testShouldResolveWithCustomFiltersFromCache()
+    public function testShouldResolveWithCustomFiltersFromCache(): void
     {
         /** @var Signer $signer */
         $signer = self::$kernel->getContainer()->get('liip_imagine.cache.signer');
@@ -167,7 +167,7 @@ public function testShouldResolveWithCustomFiltersFromCache()
         $this->assertFileExists($this->cacheRoot.'/'.$expectedCachePath);
     }
 
-    public function testShouldResolvePathWithSpecialCharactersAndWhiteSpaces()
+    public function testShouldResolvePathWithSpecialCharactersAndWhiteSpaces(): void
     {
         $this->filesystem->dumpFile(
             $this->cacheRoot.'/thumbnail_web_path/images/foo bar.jpeg',
diff --git a/Tests/Functional/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php b/Tests/Functional/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
index 03855d9df..d49e6513e 100644
--- a/Tests/Functional/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
+++ b/Tests/Functional/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
@@ -19,7 +19,7 @@
  */
 class NoCacheWebPathResolverTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainer()
+    public function testCouldBeGetFromContainer(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Cache/SignerTest.php b/Tests/Functional/Imagine/Cache/SignerTest.php
index ce8154ae9..051b7edbb 100644
--- a/Tests/Functional/Imagine/Cache/SignerTest.php
+++ b/Tests/Functional/Imagine/Cache/SignerTest.php
@@ -19,7 +19,7 @@
  */
 class SignerTest extends AbstractWebTestCase
 {
-    public function testGetAsService()
+    public function testGetAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Data/DataManagerTest.php b/Tests/Functional/Imagine/Data/DataManagerTest.php
index 9f8abe018..d71975684 100644
--- a/Tests/Functional/Imagine/Data/DataManagerTest.php
+++ b/Tests/Functional/Imagine/Data/DataManagerTest.php
@@ -19,7 +19,7 @@
  */
 class DataManagerTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Filter/FilterManagerTest.php b/Tests/Functional/Imagine/Filter/FilterManagerTest.php
index e10357f75..dbb29594b 100644
--- a/Tests/Functional/Imagine/Filter/FilterManagerTest.php
+++ b/Tests/Functional/Imagine/Filter/FilterManagerTest.php
@@ -19,7 +19,7 @@
  */
 class FilterManagerTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
index 85a4c6453..7f046633c 100644
--- a/Tests/Functional/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
@@ -19,7 +19,7 @@
  */
 class DownscaleFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Filter/Loader/FlipFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/FlipFilterLoaderTest.php
index 01a605ae7..375d0ccc6 100644
--- a/Tests/Functional/Imagine/Filter/Loader/FlipFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/FlipFilterLoaderTest.php
@@ -11,6 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\Functional\Imagine\Filter\Loader;
 
+use Liip\ImagineBundle\Imagine\Filter\Loader\FlipFilterLoader;
 use Liip\ImagineBundle\Tests\Functional\AbstractWebTestCase;
 
 /**
@@ -18,11 +19,11 @@
  */
 class FlipFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
         $this->assertInstanceOf(
-            '\Liip\ImagineBundle\Imagine\Filter\Loader\FlipFilterLoader',
+            FlipFilterLoader::class,
             self::$kernel->getContainer()->get('liip_imagine.filter.loader.flip')
         );
     }
diff --git a/Tests/Functional/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
index 26a4cd999..68d1e7c51 100644
--- a/Tests/Functional/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
@@ -21,7 +21,7 @@
  */
 class GrayscaleFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
index e73fbcec1..ebe62f84b 100644
--- a/Tests/Functional/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
@@ -19,7 +19,7 @@
  */
 class InterlaceFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/Imagine/Filter/Loader/ResampleFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
index ed4c65d08..e2c91e15d 100644
--- a/Tests/Functional/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
@@ -11,6 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\Functional\Imagine\Filter\Loader;
 
+use Liip\ImagineBundle\Imagine\Filter\Loader\ResampleFilterLoader;
 use Liip\ImagineBundle\Tests\Functional\AbstractWebTestCase;
 
 /**
@@ -18,12 +19,12 @@
  */
 class ResampleFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testContainerHasService()
+    public function testContainerHasService(): void
     {
         $this->createClient();
 
         $this->assertInstanceOf(
-            '\Liip\ImagineBundle\Imagine\Filter\Loader\ResampleFilterLoader',
+            ResampleFilterLoader::class,
             self::$kernel->getContainer()->get('liip_imagine.filter.loader.resample')
         );
     }
diff --git a/Tests/Functional/Imagine/Filter/Loader/RotateFilterLoaderTest.php b/Tests/Functional/Imagine/Filter/Loader/RotateFilterLoaderTest.php
index 2e6fc0735..044e6a8e5 100644
--- a/Tests/Functional/Imagine/Filter/Loader/RotateFilterLoaderTest.php
+++ b/Tests/Functional/Imagine/Filter/Loader/RotateFilterLoaderTest.php
@@ -21,7 +21,7 @@
  */
 class RotateFilterLoaderTest extends AbstractWebTestCase
 {
-    public function testCouldBeGetFromContainerAsService()
+    public function testCouldBeGetFromContainerAsService(): void
     {
         $this->createClient();
 
diff --git a/Tests/Functional/app/AppKernel.php b/Tests/Functional/app/AppKernel.php
index f9f835a74..2bdb24023 100644
--- a/Tests/Functional/app/AppKernel.php
+++ b/Tests/Functional/app/AppKernel.php
@@ -48,8 +48,6 @@ public function getLogDir()
     }
 
     /**
-     * @param \Symfony\Component\Config\Loader\LoaderInterface $loader
-     *
      * @throws \Exception
      */
     public function registerContainerConfiguration(LoaderInterface $loader)
diff --git a/Tests/Imagine/Cache/CacheManagerTest.php b/Tests/Imagine/Cache/CacheManagerTest.php
index 60edc0513..542bb862f 100644
--- a/Tests/Imagine/Cache/CacheManagerTest.php
+++ b/Tests/Imagine/Cache/CacheManagerTest.php
@@ -19,6 +19,7 @@
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
 use Liip\ImagineBundle\Tests\Fixtures\CacheManagerAwareResolver;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Contracts\EventDispatcher\EventDispatcherInterface as ContractsEventDispatcherInterface;
@@ -28,7 +29,7 @@
  */
 class CacheManagerTest extends AbstractTest
 {
-    public function testAddCacheManagerAwareResolver()
+    public function testAddCacheManagerAwareResolver(): void
     {
         $cacheManager = new CacheManager($this->createFilterConfigurationMock(), $this->createRouterInterfaceMock(), new Signer('secret'), $this->createEventDispatcherInterfaceMock());
 
@@ -41,7 +42,7 @@ public function testAddCacheManagerAwareResolver()
         $cacheManager->addResolver('thumbnail', $resolver);
     }
 
-    public function testGetBrowserPathWithoutResolver()
+    public function testGetBrowserPathWithoutResolver(): void
     {
         $this->expectException(\OutOfBoundsException::class);
         $this->expectExceptionMessage('Could not find resolver "default" for "thumbnail" filter type');
@@ -61,7 +62,7 @@ public function testGetBrowserPathWithoutResolver()
         $cacheManager->getBrowserPath('cats.jpeg', 'thumbnail');
     }
 
-    public function testGetRuntimePath()
+    public function testGetRuntimePath(): void
     {
         $config = $this->createFilterConfigurationMock();
         $cacheManager = new CacheManager($config, $this->createRouterInterfaceMock(), new Signer('secret'), $this->createEventDispatcherInterfaceMock());
@@ -75,7 +76,7 @@ public function testGetRuntimePath()
         $this->assertSame('rc/ILfTutxX/image.jpg', $rcPath);
     }
 
-    public function testDefaultResolverUsedIfNoneSetOnGetBrowserPath()
+    public function testDefaultResolverUsedIfNoneSetOnGetBrowserPath(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -113,7 +114,7 @@ public function testDefaultResolverUsedIfNoneSetOnGetBrowserPath()
         $this->assertSame('http://a/path/to/an/image.png', $actualBrowserPath);
     }
 
-    public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBrowserPath()
+    public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBrowserPath(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -150,7 +151,7 @@ public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBr
         $this->assertSame('/media/cache/thumbnail/cats.jpeg', $actualBrowserPath);
     }
 
-    public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBrowserPathWithRuntimeConfig()
+    public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBrowserPathWithRuntimeConfig(): void
     {
         $runtimeConfig = [
             'thumbnail' => [
@@ -198,7 +199,7 @@ public function testFilterActionUrlGeneratedAndReturnIfResolverReturnNullOnGetBr
      *
      * @param string $path
      */
-    public function testResolveInvalidPath($path)
+    public function testResolveInvalidPath($path): void
     {
         $this->expectException(\Symfony\Component\HttpKernel\Exception\NotFoundHttpException::class);
 
@@ -212,7 +213,7 @@ public function testResolveInvalidPath($path)
         $cacheManager->resolve($path, 'thumbnail');
     }
 
-    public function testThrowsIfConcreteResolverNotExists()
+    public function testThrowsIfConcreteResolverNotExists(): void
     {
         $this->expectException(\OutOfBoundsException::class);
         $this->expectExceptionMessage('Could not find resolver "default" for "thumbnail" filter type');
@@ -227,7 +228,7 @@ public function testThrowsIfConcreteResolverNotExists()
         $this->assertFalse($cacheManager->resolve('cats.jpeg', 'thumbnail'));
     }
 
-    public function testFallbackToDefaultResolver()
+    public function testFallbackToDefaultResolver(): void
     {
         $binary = new Binary('aContent', 'image/png', 'png');
 
@@ -275,7 +276,7 @@ public function testFallbackToDefaultResolver()
         $cacheManager->remove('/thumbs/cats.jpeg', 'thumbnail');
     }
 
-    public function testGenerateUrl()
+    public function testGenerateUrl(): void
     {
         $path = 'thePath';
         $expectedUrl = 'theUrl';
@@ -307,7 +308,7 @@ public function testGenerateUrl()
         );
     }
 
-    public function testRemoveCacheForPathAndFilterOnRemove()
+    public function testRemoveCacheForPathAndFilterOnRemove(): void
     {
         $expectedPath = 'thePath';
         $expectedFilter = 'theFilter';
@@ -333,7 +334,7 @@ public function testRemoveCacheForPathAndFilterOnRemove()
         $cacheManager->remove($expectedPath, $expectedFilter);
     }
 
-    public function testRemoveCacheForPathAndSomeFiltersOnRemove()
+    public function testRemoveCacheForPathAndSomeFiltersOnRemove(): void
     {
         $expectedPath = 'thePath';
         $expectedFilterOne = 'theFilterOne';
@@ -367,7 +368,7 @@ public function testRemoveCacheForPathAndSomeFiltersOnRemove()
         $cacheManager->remove($expectedPath, [$expectedFilterOne, $expectedFilterTwo]);
     }
 
-    public function testRemoveCacheForSomePathsAndFilterOnRemove()
+    public function testRemoveCacheForSomePathsAndFilterOnRemove(): void
     {
         $expectedPathOne = 'thePathOne';
         $expectedPathTwo = 'thePathTwo';
@@ -397,7 +398,7 @@ public function testRemoveCacheForSomePathsAndFilterOnRemove()
         $cacheManager->remove([$expectedPathOne, $expectedPathTwo], $expectedFilter);
     }
 
-    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
+    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove(): void
     {
         $expectedPathOne = 'thePath';
         $expectedPathTwo = 'thePath';
@@ -435,7 +436,7 @@ public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
         );
     }
 
-    public function testRemoveCacheForAllFiltersOnRemove()
+    public function testRemoveCacheForAllFiltersOnRemove(): void
     {
         $expectedFilterOne = 'theFilterOne';
         $expectedFilterTwo = 'theFilterTwo';
@@ -475,7 +476,7 @@ public function testRemoveCacheForAllFiltersOnRemove()
         $cacheManager->remove();
     }
 
-    public function testRemoveCacheForPathAndAllFiltersOnRemove()
+    public function testRemoveCacheForPathAndAllFiltersOnRemove(): void
     {
         $expectedFilterOne = 'theFilterOne';
         $expectedFilterTwo = 'theFilterTwo';
@@ -516,7 +517,7 @@ public function testRemoveCacheForPathAndAllFiltersOnRemove()
         $cacheManager->remove($expectedPath);
     }
 
-    public function testAggregateFiltersByResolverOnRemove()
+    public function testAggregateFiltersByResolverOnRemove(): void
     {
         $expectedFilterOne = 'theFilterOne';
         $expectedFilterTwo = 'theFilterTwo';
@@ -543,7 +544,7 @@ public function testAggregateFiltersByResolverOnRemove()
         $cacheManager->remove(null, [$expectedFilterOne, $expectedFilterTwo]);
     }
 
-    public function testShouldDispatchCachePreResolveEvent()
+    public function testShouldDispatchCachePreResolveEvent(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
@@ -551,7 +552,7 @@ public function testShouldDispatchCachePreResolveEvent()
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [
                 new CacheResolveEvent('cats.jpg', 'thumbnail'),
-                ImagineEvents::PRE_RESOLVE
+                ImagineEvents::PRE_RESOLVE,
             ]));
 
         $cacheManager = new CacheManager(
@@ -565,7 +566,7 @@ public function testShouldDispatchCachePreResolveEvent()
         $cacheManager->resolve('cats.jpg', 'thumbnail');
     }
 
-    public function testShouldDispatchCachePostResolveEvent()
+    public function testShouldDispatchCachePostResolveEvent(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
@@ -573,7 +574,7 @@ public function testShouldDispatchCachePostResolveEvent()
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [
                 new CacheResolveEvent('cats.jpg', 'thumbnail'),
-                ImagineEvents::POST_RESOLVE
+                ImagineEvents::POST_RESOLVE,
             ]));
 
         $cacheManager = new CacheManager(
@@ -587,7 +588,7 @@ public function testShouldDispatchCachePostResolveEvent()
         $cacheManager->resolve('cats.jpg', 'thumbnail');
     }
 
-    public function testShouldAllowToPassChangedDataFromPreResolveEventToResolver()
+    public function testShouldAllowToPassChangedDataFromPreResolveEventToResolver(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
@@ -595,9 +596,9 @@ public function testShouldAllowToPassChangedDataFromPreResolveEventToResolver()
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [
                 $this->isInstanceOf(CacheResolveEvent::class),
-                ImagineEvents::PRE_RESOLVE
+                ImagineEvents::PRE_RESOLVE,
             ]))
-            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event, $name) {
+            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event) {
                 $event->setPath('changed_path');
                 $event->setFilter('changed_filter');
             }));
@@ -619,13 +620,13 @@ public function testShouldAllowToPassChangedDataFromPreResolveEventToResolver()
         $cacheManager->resolve('cats.jpg', 'thumbnail');
     }
 
-    public function testShouldAllowToGetResolverByFilterChangedInPreResolveEvent()
+    public function testShouldAllowToGetResolverByFilterChangedInPreResolveEvent(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
             ->expects($this->at(0))
             ->method('dispatch')
-            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event, $name) {
+            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event) {
                 $event->setFilter('thumbnail');
             }));
 
@@ -648,7 +649,7 @@ public function testShouldAllowToGetResolverByFilterChangedInPreResolveEvent()
         $cacheManager->resolve('cats.jpg', 'default');
     }
 
-    public function testShouldAllowToPassChangedDataFromPreResolveEventToPostResolveEvent()
+    public function testShouldAllowToPassChangedDataFromPreResolveEventToPostResolveEvent(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
@@ -656,9 +657,9 @@ public function testShouldAllowToPassChangedDataFromPreResolveEventToPostResolve
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [
                 $this->isInstanceOf(CacheResolveEvent::class),
-                ImagineEvents::PRE_RESOLVE
+                ImagineEvents::PRE_RESOLVE,
             ]))
-            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event, $name) {
+            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function (CacheResolveEvent $event) {
                 $event->setPath('changed_path');
                 $event->setFilter('changed_filter');
             }));
@@ -668,8 +669,9 @@ public function testShouldAllowToPassChangedDataFromPreResolveEventToPostResolve
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [$this->logicalAnd(
                 $this->isInstanceOf(CacheResolveEvent::class),
-                $this->attributeEqualTo('path', 'changed_path'),
-                $this->attributeEqualTo('filter', 'changed_filter')
+                $this->callback(function (CacheResolveEvent $event) {
+                    return 'changed_filter' === $event->getFilter() && 'changed_path' === $event->getPath();
+                })
             ), ImagineEvents::POST_RESOLVE]));
 
         $cacheManager = new CacheManager(
@@ -683,7 +685,7 @@ public function testShouldAllowToPassChangedDataFromPreResolveEventToPostResolve
         $cacheManager->resolve('cats.jpg', 'thumbnail');
     }
 
-    public function testShouldReturnUrlChangedInPostResolveEvent()
+    public function testShouldReturnUrlChangedInPostResolveEvent(): void
     {
         $dispatcher = $this->createEventDispatcherInterfaceMock();
         $dispatcher
@@ -691,9 +693,9 @@ public function testShouldReturnUrlChangedInPostResolveEvent()
             ->method('dispatch')
             ->with(...$this->getDispatcherArgumentsWithBC($dispatcher, [
                 $this->isInstanceOf(CacheResolveEvent::class),
-                ImagineEvents::POST_RESOLVE
+                ImagineEvents::POST_RESOLVE,
             ]))
-            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event, $name) {
+            ->willReturnCallback($this->getDispatcherCallbackWithBC($dispatcher, function ($event) {
                 $event->setUrl('changed_url');
             }));
 
@@ -709,21 +711,17 @@ public function testShouldReturnUrlChangedInPostResolveEvent()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ResolverInterface
+     * @return MockObject|ResolverInterface
      */
     private function createCacheManagerAwareResolverMock()
     {
-        return $resolver = $this
+        return $this
             ->getMockBuilder(CacheManagerAwareResolver::class)
             ->getMock();
     }
 
     /**
      * BC Layer for Symfony < 4.3
-     *
-     * @param EventDispatcherInterface $dispatcher
-     * @param callable $callable
-     * @return callable
      */
     private function getDispatcherCallbackWithBC(EventDispatcherInterface $dispatcher, callable $callable): callable
     {
@@ -738,10 +736,6 @@ private function getDispatcherCallbackWithBC(EventDispatcherInterface $dispatche
 
     /**
      * BC Layer for Symfony < 4.3
-     *
-     * @param EventDispatcherInterface $dispatcher
-     * @param array $arguments
-     * @return array
      */
     private function getDispatcherArgumentsWithBC(EventDispatcherInterface $dispatcher, array $arguments): array
     {
diff --git a/Tests/Imagine/Cache/Resolver/AmazonS3ResolverTest.php b/Tests/Imagine/Cache/Resolver/AmazonS3ResolverTest.php
index 937593034..3e202001c 100644
--- a/Tests/Imagine/Cache/Resolver/AmazonS3ResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/AmazonS3ResolverTest.php
@@ -15,20 +15,21 @@
 use Liip\ImagineBundle\Imagine\Cache\Resolver\ResolverInterface;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\Imagine\Cache\Resolver\AmazonS3Resolver
  */
 class AmazonS3ResolverTest extends AbstractTest
 {
-    public function testImplementsResolverInterface()
+    public function testImplementsResolverInterface(): void
     {
         $rc = new \ReflectionClass(AmazonS3Resolver::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverInterface::class));
     }
 
-    public function testNoDoubleSlashesInObjectUrlOnResolve()
+    public function testNoDoubleSlashesInObjectUrlOnResolve(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -40,7 +41,7 @@ public function testNoDoubleSlashesInObjectUrlOnResolve()
         $resolver->resolve('/some-folder/path.jpg', 'thumb');
     }
 
-    public function testObjUrlOptionsPassedToAmazonOnResolve()
+    public function testObjUrlOptionsPassedToAmazonOnResolve(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -53,7 +54,7 @@ public function testObjUrlOptionsPassedToAmazonOnResolve()
         $resolver->resolve('/some-folder/path.jpg', 'thumb');
     }
 
-    public function testThrowsAndLogIfCanNotCreateObjectOnAmazon()
+    public function testThrowsAndLogIfCanNotCreateObjectOnAmazon(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Imagine\Cache\Resolver\NotStorableException::class);
         $this->expectExceptionMessage('The object could not be created on Amazon S3');
@@ -76,7 +77,7 @@ public function testThrowsAndLogIfCanNotCreateObjectOnAmazon()
         $resolver->store($binary, 'foobar.jpg', 'thumb');
     }
 
-    public function testCreatedObjectOnAmazon()
+    public function testCreatedObjectOnAmazon(): void
     {
         $binary = new Binary('aContent', 'image/jpeg', 'jpeg');
 
@@ -90,7 +91,7 @@ public function testCreatedObjectOnAmazon()
         $resolver->store($binary, 'foobar.jpg', 'thumb');
     }
 
-    public function testIsStoredChecksObjectExistence()
+    public function testIsStoredChecksObjectExistence(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -103,7 +104,7 @@ public function testIsStoredChecksObjectExistence()
         $this->assertFalse($resolver->isStored('/some-folder/path.jpg', 'thumb'));
     }
 
-    public function testReturnResolvedImageUrlOnResolve()
+    public function testReturnResolvedImageUrlOnResolve(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -120,7 +121,7 @@ public function testReturnResolvedImageUrlOnResolve()
         );
     }
 
-    public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
+    public function testDoNothingIfFiltersAndPathsEmptyOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -137,7 +138,7 @@ public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
         $resolver->remove([], []);
     }
 
-    public function testRemoveCacheForPathAndFilterOnRemove()
+    public function testRemoveCacheForPathAndFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -155,7 +156,7 @@ public function testRemoveCacheForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testRemoveCacheForSomePathsAndFilterOnRemove()
+    public function testRemoveCacheForSomePathsAndFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -183,7 +184,7 @@ public function testRemoveCacheForSomePathsAndFilterOnRemove()
         $resolver->remove(['pathOne.jpg', 'pathTwo.jpg'], ['filter']);
     }
 
-    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
+    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -234,7 +235,7 @@ public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
         );
     }
 
-    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
+    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -250,7 +251,7 @@ public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
         $resolver->remove(['path.jpg'], ['filter']);
     }
 
-    public function testLogIfNotDeletedForPathAndFilterOnRemove()
+    public function testLogIfNotDeletedForPathAndFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -273,7 +274,7 @@ public function testLogIfNotDeletedForPathAndFilterOnRemove()
         $resolver->remove(['path.jpg'], ['filter']);
     }
 
-    public function testRemoveCacheForFilterOnRemove()
+    public function testRemoveCacheForFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -286,7 +287,7 @@ public function testRemoveCacheForFilterOnRemove()
         $resolver->remove([], ['filter']);
     }
 
-    public function testRemoveCacheForSomeFiltersOnRemove()
+    public function testRemoveCacheForSomeFiltersOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -299,7 +300,7 @@ public function testRemoveCacheForSomeFiltersOnRemove()
         $resolver->remove([], ['filterOne', 'filterTwo']);
     }
 
-    public function testLogIfBatchNotDeletedForFilterOnRemove()
+    public function testLogIfBatchNotDeletedForFilterOnRemove(): void
     {
         $s3 = $this->createAmazonS3Mock();
         $s3
@@ -321,7 +322,7 @@ public function testLogIfBatchNotDeletedForFilterOnRemove()
     /**
      * @param bool $ok
      *
-     * @return \PHPUnit_Framework_MockObject_MockObject|\CFResponse
+     * @return MockObject|\CFResponse
      */
     protected function createCFResponseMock($ok = true)
     {
@@ -335,7 +336,7 @@ protected function createCFResponseMock($ok = true)
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|\AmazonS3
+     * @return MockObject|\AmazonS3
      */
     protected function createAmazonS3Mock()
     {
diff --git a/Tests/Imagine/Cache/Resolver/AwsS3ResolverTest.php b/Tests/Imagine/Cache/Resolver/AwsS3ResolverTest.php
index 9539cd669..9f358a966 100644
--- a/Tests/Imagine/Cache/Resolver/AwsS3ResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/AwsS3ResolverTest.php
@@ -17,20 +17,21 @@
 use Liip\ImagineBundle\Imagine\Cache\Resolver\ResolverInterface;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\Imagine\Cache\Resolver\AwsS3Resolver
  */
 class AwsS3ResolverTest extends AbstractTest
 {
-    public function testImplementsResolverInterface()
+    public function testImplementsResolverInterface(): void
     {
         $rc = new \ReflectionClass(AwsS3Resolver::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverInterface::class));
     }
 
-    public function testNoDoubleSlashesInObjectUrlOnResolve()
+    public function testNoDoubleSlashesInObjectUrlOnResolve(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -42,7 +43,7 @@ public function testNoDoubleSlashesInObjectUrlOnResolve()
         $resolver->resolve('/some-folder/path.jpg', 'thumb');
     }
 
-    public function testObjUrlOptionsPassedToS3ClintOnResolve()
+    public function testObjUrlOptionsPassedToS3ClintOnResolve(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -55,7 +56,7 @@ public function testObjUrlOptionsPassedToS3ClintOnResolve()
         $resolver->resolve('/some-folder/path.jpg', 'thumb');
     }
 
-    public function testLogNotCreatedObjects()
+    public function testLogNotCreatedObjects(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Imagine\Cache\Resolver\NotStorableException::class);
         $this->expectExceptionMessage('The object could not be created on Amazon S3');
@@ -78,7 +79,7 @@ public function testLogNotCreatedObjects()
         $resolver->store($binary, 'foobar.jpg', 'thumb');
     }
 
-    public function testCreateObjectOnAmazon()
+    public function testCreateObjectOnAmazon(): void
     {
         $binary = new Binary('aContent', 'image/jpeg', 'jpeg');
 
@@ -92,7 +93,7 @@ public function testCreateObjectOnAmazon()
         $resolver->store($binary, 'thumb/foobar.jpg', 'thumb');
     }
 
-    public function testObjectOptionsPassedToS3ClintOnCreate()
+    public function testObjectOptionsPassedToS3ClintOnCreate(): void
     {
         $binary = new Binary('aContent', 'image/jpeg', 'jpeg');
 
@@ -114,7 +115,7 @@ public function testObjectOptionsPassedToS3ClintOnCreate()
         $resolver->store($binary, 'images/foobar.jpg', 'filter');
     }
 
-    public function testIsStoredChecksObjectExistence()
+    public function testIsStoredChecksObjectExistence(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -127,7 +128,7 @@ public function testIsStoredChecksObjectExistence()
         $this->assertFalse($resolver->isStored('/some-folder/path.jpg', 'thumb'));
     }
 
-    public function testReturnResolvedImageUrlOnResolve()
+    public function testReturnResolvedImageUrlOnResolve(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -144,7 +145,7 @@ public function testReturnResolvedImageUrlOnResolve()
         );
     }
 
-    public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
+    public function testDoNothingIfFiltersAndPathsEmptyOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -161,7 +162,7 @@ public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
         $resolver->remove([], []);
     }
 
-    public function testRemoveCacheForPathAndFilterOnRemove()
+    public function testRemoveCacheForPathAndFilterOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -182,7 +183,7 @@ public function testRemoveCacheForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testRemoveCacheForSomePathsAndFilterOnRemove()
+    public function testRemoveCacheForSomePathsAndFilterOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -219,7 +220,7 @@ public function testRemoveCacheForSomePathsAndFilterOnRemove()
         );
     }
 
-    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
+    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -282,7 +283,7 @@ public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
         );
     }
 
-    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
+    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -298,7 +299,7 @@ public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testCatchAndLogExceptionsForPathAndFilterOnRemove()
+    public function testCatchAndLogExceptionsForPathAndFilterOnRemove(): void
     {
         $s3 = $this->getS3ClientMock();
         $s3
@@ -321,7 +322,7 @@ public function testCatchAndLogExceptionsForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testRemoveCacheForFilterOnRemove()
+    public function testRemoveCacheForFilterOnRemove(): void
     {
         $expectedBucket = 'images.example.com';
         $expectedFilter = 'theFilter';
@@ -336,7 +337,7 @@ public function testRemoveCacheForFilterOnRemove()
         $resolver->remove([], [$expectedFilter]);
     }
 
-    public function testRemoveCacheForSomeFiltersOnRemove()
+    public function testRemoveCacheForSomeFiltersOnRemove(): void
     {
         $expectedBucket = 'images.example.com';
         $expectedFilterOne = 'theFilterOne';
@@ -352,7 +353,7 @@ public function testRemoveCacheForSomeFiltersOnRemove()
         $resolver->remove([], [$expectedFilterOne, $expectedFilterTwo]);
     }
 
-    public function testCatchAndLogExceptionForFilterOnRemove()
+    public function testCatchAndLogExceptionForFilterOnRemove(): void
     {
         $expectedBucket = 'images.example.com';
         $expectedFilter = 'theFilter';
@@ -374,7 +375,7 @@ public function testCatchAndLogExceptionForFilterOnRemove()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|Model
+     * @return MockObject|Model
      */
     protected function getS3ResponseMock()
     {
@@ -382,7 +383,7 @@ protected function getS3ResponseMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|\Aws\S3\S3Client
+     * @return MockObject|\Aws\S3\S3Client
      */
     protected function getS3ClientMock()
     {
diff --git a/Tests/Imagine/Cache/Resolver/CacheResolverTest.php b/Tests/Imagine/Cache/Resolver/CacheResolverTest.php
index fe22a0d58..0c540fb23 100644
--- a/Tests/Imagine/Cache/Resolver/CacheResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/CacheResolverTest.php
@@ -35,7 +35,7 @@ protected function setUp()
         parent::setUp();
     }
 
-    public function testResolveIsSavedToCache()
+    public function testResolveIsSavedToCache(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -53,7 +53,7 @@ public function testResolveIsSavedToCache()
         $this->assertSame($this->webPath, $cacheResolver->resolve($this->path, $this->filter));
     }
 
-    public function testNotCallInternalResolverIfCachedOnIsStored()
+    public function testNotCallInternalResolverIfCachedOnIsStored(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -74,7 +74,7 @@ public function testNotCallInternalResolverIfCachedOnIsStored()
         $this->assertTrue($cacheResolver->isStored($this->path, $this->filter));
     }
 
-    public function testCallInternalResolverIfNotCachedOnIsStored()
+    public function testCallInternalResolverIfNotCachedOnIsStored(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -88,7 +88,7 @@ public function testCallInternalResolverIfNotCachedOnIsStored()
         $this->assertTrue($cacheResolver->isStored($this->path, $this->filter));
     }
 
-    public function testStoreIsForwardedToResolver()
+    public function testStoreIsForwardedToResolver(): void
     {
         $binary = new Binary('aContent', 'image/jpeg', 'jpg');
 
@@ -105,7 +105,7 @@ public function testStoreIsForwardedToResolver()
         $this->assertNull($cacheResolver->store($binary, $this->webPath, $this->filter));
     }
 
-    public function testSavesToCacheIfInternalResolverReturnUrlOnResolve()
+    public function testSavesToCacheIfInternalResolverReturnUrlOnResolve(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -124,7 +124,7 @@ public function testSavesToCacheIfInternalResolverReturnUrlOnResolve()
         $cacheResolver->resolve($this->path, $this->filter);
     }
 
-    public function testRemoveSinglePathCacheOnRemove()
+    public function testRemoveSinglePathCacheOnRemove(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -154,7 +154,7 @@ public function testRemoveSinglePathCacheOnRemove()
         $this->assertCount(0, $this->getCacheEntries($cache));
     }
 
-    public function testRemoveAllFilterCacheOnRemove()
+    public function testRemoveAllFilterCacheOnRemove(): void
     {
         $resolver = $this->createCacheResolverInterfaceMock();
         $resolver
@@ -191,12 +191,8 @@ public function testRemoveAllFilterCacheOnRemove()
      * version, it may or may not be there depending on doctrine-cache
      * version. There's no point in checking it anyway since it's a detail
      * of doctrine cache implementation.
-     *
-     * @param ArrayCache $cache
-     *
-     * @return array
      */
-    private function getCacheEntries(ArrayCache $cache)
+    private function getCacheEntries(ArrayCache $cache): array
     {
         $cacheEntries = $this->readAttribute($cache, 'data');
         unset($cacheEntries['DoctrineNamespaceCacheKey[]']);
diff --git a/Tests/Imagine/Cache/Resolver/FlysystemResolverTest.php b/Tests/Imagine/Cache/Resolver/FlysystemResolverTest.php
index 827510dad..8c1574e5a 100644
--- a/Tests/Imagine/Cache/Resolver/FlysystemResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/FlysystemResolverTest.php
@@ -16,6 +16,7 @@
 use Liip\ImagineBundle\Imagine\Cache\Resolver\ResolverInterface;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\Routing\RequestContext;
 
 /**
@@ -32,14 +33,14 @@ public function setUp()
         }
     }
 
-    public function testImplementsResolverInterface()
+    public function testImplementsResolverInterface(): void
     {
         $rc = new \ReflectionClass(FlysystemResolver::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverInterface::class));
     }
 
-    public function testResolveUriForFilter()
+    public function testResolveUriForFilter(): void
     {
         $resolver = new FlysystemResolver($this->createFlySystemMock(), new RequestContext(), 'http://images.example.com');
 
@@ -49,7 +50,7 @@ public function testResolveUriForFilter()
         );
     }
 
-    public function testRemoveObjectsForFilter()
+    public function testRemoveObjectsForFilter(): void
     {
         $expectedFilter = 'theFilter';
         $fs = $this->createFlySystemMock();
@@ -62,7 +63,7 @@ public function testRemoveObjectsForFilter()
         $resolver->remove([], [$expectedFilter]);
     }
 
-    public function testCreateObjectInAdapter()
+    public function testCreateObjectInAdapter(): void
     {
         $binary = new Binary('aContent', 'image/jpeg', 'jpeg');
 
@@ -77,7 +78,7 @@ public function testCreateObjectInAdapter()
         $this->assertNull($resolver->store($binary, 'thumb/foobar.jpg', 'thumb'));
     }
 
-    public function testIsStoredChecksObjectExistence()
+    public function testIsStoredChecksObjectExistence(): void
     {
         $fs = $this->createFlySystemMock();
         $fs
@@ -90,7 +91,7 @@ public function testIsStoredChecksObjectExistence()
         $this->assertFalse($resolver->isStored('/some-folder/path.jpg', 'thumb'));
     }
 
-    public function testReturnResolvedImageUrlOnResolve()
+    public function testReturnResolvedImageUrlOnResolve(): void
     {
         $fs = $this->createFlySystemMock();
 
@@ -102,7 +103,7 @@ public function testReturnResolvedImageUrlOnResolve()
         );
     }
 
-    public function testResolveWithPrefixCacheEmpty()
+    public function testResolveWithPrefixCacheEmpty(): void
     {
         $resolver = new FlysystemResolver($this->createFlySystemMock(), new RequestContext(), 'http://images.example.com', '');
 
@@ -112,7 +113,7 @@ public function testResolveWithPrefixCacheEmpty()
         );
     }
 
-    public function testRemoveCacheForPathAndFilterOnRemove()
+    public function testRemoveCacheForPathAndFilterOnRemove(): void
     {
         $fs = $this->createFlySystemMock();
         $fs
@@ -130,7 +131,7 @@ public function testRemoveCacheForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testRemoveCacheForSomePathsAndFilterOnRemove()
+    public function testRemoveCacheForSomePathsAndFilterOnRemove(): void
     {
         $fs = $this->createFlySystemMock();
         $fs
@@ -161,7 +162,7 @@ public function testRemoveCacheForSomePathsAndFilterOnRemove()
         );
     }
 
-    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
+    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove(): void
     {
         $fs = $this->createFlySystemMock();
         $fs
@@ -212,7 +213,7 @@ public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
         );
     }
 
-    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
+    public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove(): void
     {
         $fs = $this->createFlySystemMock();
         $fs
@@ -228,7 +229,7 @@ public function testDoNothingWhenObjectNotExistForPathAndFilterOnRemove()
         $resolver->remove(['some-folder/path.jpg'], ['thumb']);
     }
 
-    public function testRemoveCacheForFilterOnRemove()
+    public function testRemoveCacheForFilterOnRemove(): void
     {
         $expectedFilter = 'theFilter';
 
@@ -242,7 +243,7 @@ public function testRemoveCacheForFilterOnRemove()
         $resolver->remove([], [$expectedFilter]);
     }
 
-    public function testRemoveCacheForSomeFiltersOnRemove()
+    public function testRemoveCacheForSomeFiltersOnRemove(): void
     {
         $expectedFilterOne = 'theFilterOne';
         $expectedFilterTwo = 'theFilterTwo';
@@ -262,7 +263,7 @@ public function testRemoveCacheForSomeFiltersOnRemove()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|Filesystem
+     * @return MockObject|Filesystem
      */
     protected function createFlySystemMock()
     {
diff --git a/Tests/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php b/Tests/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
index 2ca88f27c..90e8fb974 100644
--- a/Tests/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/NoCacheWebPathResolverTest.php
@@ -21,28 +21,28 @@
  */
 class NoCacheWebPathResolverTest extends AbstractTest
 {
-    public function testCouldBeConstructedWithRequestContextAsArgument()
+    public function testCouldBeConstructedWithRequestContextAsArgument(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext());
 
         $this->assertInstanceOf(NoCacheWebPathResolver::class, $resolver);
     }
 
-    public function testComposeSchemaHostAndPathOnResolve()
+    public function testComposeSchemaHostAndPathOnResolve(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext('', 'GET', 'thehost', 'theSchema'));
 
         $this->assertSame('theschema://thehost/aPath', $resolver->resolve('aPath', 'aFilter'));
     }
 
-    public function testDoNothingOnStore()
+    public function testDoNothingOnStore(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext());
 
         $this->assertNull($resolver->store(new Binary('aContent', 'image/jpeg', 'jpg'), 'a/path', 'aFilter'));
     }
 
-    public function testDoNothingForPathAndFilterOnRemove()
+    public function testDoNothingForPathAndFilterOnRemove(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext());
         $resolver->remove(['a/path'], ['aFilter']);
@@ -50,7 +50,7 @@ public function testDoNothingForPathAndFilterOnRemove()
         $this->assertInstanceOf(NoCacheWebPathResolver::class, $resolver);
     }
 
-    public function testDoNothingForSomePathsAndSomeFiltersOnRemove()
+    public function testDoNothingForSomePathsAndSomeFiltersOnRemove(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext());
         $resolver->remove(['foo', 'bar'], ['foo', 'bar']);
@@ -58,7 +58,7 @@ public function testDoNothingForSomePathsAndSomeFiltersOnRemove()
         $this->assertInstanceOf(NoCacheWebPathResolver::class, $resolver);
     }
 
-    public function testDoNothingForEmptyPathAndEmptyFilterOnRemove()
+    public function testDoNothingForEmptyPathAndEmptyFilterOnRemove(): void
     {
         $resolver = new NoCacheWebPathResolver(new RequestContext());
         $resolver->remove([], []);
diff --git a/Tests/Imagine/Cache/Resolver/ProxyResolverTest.php b/Tests/Imagine/Cache/Resolver/ProxyResolverTest.php
index 7c6fca369..99658397b 100644
--- a/Tests/Imagine/Cache/Resolver/ProxyResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/ProxyResolverTest.php
@@ -15,6 +15,7 @@
 use Liip\ImagineBundle\Imagine\Cache\Resolver\ResolverInterface;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\Imagine\Cache\Resolver\ProxyResolver
@@ -22,7 +23,7 @@
 class ProxyResolverTest extends AbstractTest
 {
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|ResolverInterface
+     * @var MockObject|ResolverInterface
      */
     private $primaryResolver;
 
@@ -37,7 +38,7 @@ public function setUp()
         $this->resolver = new ProxyResolver($this->primaryResolver, ['http://images.example.com']);
     }
 
-    public function testProxyCallAndRewriteReturnedUrlOnResolve()
+    public function testProxyCallAndRewriteReturnedUrlOnResolve(): void
     {
         $expectedPath = '/foo/bar/bazz.png';
         $expectedFilter = 'test';
@@ -53,7 +54,7 @@ public function testProxyCallAndRewriteReturnedUrlOnResolve()
         $this->assertSame('http://images.example.com/thumbs/foo/bar/bazz.png', $result);
     }
 
-    public function testProxyCallAndRewriteReturnedUrlEvenSchemesDiffersOnResolve()
+    public function testProxyCallAndRewriteReturnedUrlEvenSchemesDiffersOnResolve(): void
     {
         $expectedPath = '/foo/bar/bazz.png';
         $expectedFilter = 'test';
@@ -69,7 +70,7 @@ public function testProxyCallAndRewriteReturnedUrlEvenSchemesDiffersOnResolve()
         $this->assertSame('http://images.example.com/thumbs/foo/bar/bazz.png', $result);
     }
 
-    public function testProxyCallAndRewriteReturnedUrlWithMatchReplaceOnResolve()
+    public function testProxyCallAndRewriteReturnedUrlWithMatchReplaceOnResolve(): void
     {
         $expectedPath = '/foo/bar/bazz.png';
         $expectedFilter = 'test';
@@ -89,7 +90,7 @@ public function testProxyCallAndRewriteReturnedUrlWithMatchReplaceOnResolve()
         $this->assertSame('http://images.example.com/thumbs/foo/bar/bazz.png', $result);
     }
 
-    public function testProxyCallAndRewriteReturnedUrlWithRegExpOnResolve()
+    public function testProxyCallAndRewriteReturnedUrlWithRegExpOnResolve(): void
     {
         $expectedPath = '/foo/bar/bazz.png';
         $expectedFilter = 'test';
@@ -109,7 +110,7 @@ public function testProxyCallAndRewriteReturnedUrlWithRegExpOnResolve()
         $this->assertSame('http://bar.com/thumbs/foo/bar/bazz.png', $result);
     }
 
-    public function testProxyCallAndReturnedValueOnIsStored()
+    public function testProxyCallAndReturnedValueOnIsStored(): void
     {
         $expectedPath = 'thePath';
         $expectedFilter = 'theFilter';
@@ -123,7 +124,7 @@ public function testProxyCallAndReturnedValueOnIsStored()
         $this->assertTrue($this->resolver->isStored($expectedPath, $expectedFilter));
     }
 
-    public function testProxyCallOnStore()
+    public function testProxyCallOnStore(): void
     {
         $expectedPath = 'thePath';
         $expectedFilter = 'theFilter';
@@ -137,7 +138,7 @@ public function testProxyCallOnStore()
         $this->resolver->store($expectedBinary, $expectedPath, $expectedFilter);
     }
 
-    public function testProxyCallOnRemove()
+    public function testProxyCallOnRemove(): void
     {
         $expectedPaths = ['thePath'];
         $expectedFilters = ['theFilter'];
diff --git a/Tests/Imagine/Cache/Resolver/WebPathResolverTest.php b/Tests/Imagine/Cache/Resolver/WebPathResolverTest.php
index 0eb27b54a..dba6ce7ef 100644
--- a/Tests/Imagine/Cache/Resolver/WebPathResolverTest.php
+++ b/Tests/Imagine/Cache/Resolver/WebPathResolverTest.php
@@ -14,6 +14,7 @@
 use Liip\ImagineBundle\Imagine\Cache\Resolver\ResolverInterface;
 use Liip\ImagineBundle\Imagine\Cache\Resolver\WebPathResolver;
 use Liip\ImagineBundle\Model\Binary;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Filesystem\Filesystem;
 use Symfony\Component\Routing\RequestContext;
@@ -52,14 +53,14 @@ public function tearDown()
         $this->filesystem->remove($this->basePath);
     }
 
-    public function testImplementsResolverInterface()
+    public function testImplementsResolverInterface(): void
     {
         $rc = new \ReflectionClass(WebPathResolver::class);
 
         $this->assertTrue($rc->implementsInterface(ResolverInterface::class));
     }
 
-    public function testCouldBeConstructedWithRequiredArguments()
+    public function testCouldBeConstructedWithRequiredArguments(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $requestContext = new RequestContext();
@@ -72,7 +73,7 @@ public function testCouldBeConstructedWithRequiredArguments()
         $this->assertAttributeSame($webRoot, 'webRoot', $resolver);
     }
 
-    public function testCouldBeConstructedWithOptionalArguments()
+    public function testCouldBeConstructedWithOptionalArguments(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -84,7 +85,7 @@ public function testCouldBeConstructedWithOptionalArguments()
         $this->assertAttributeSame('theCachePrefix', 'cachePrefix', $resolver);
     }
 
-    public function testTrimRightSlashFromWebPathOnConstruct()
+    public function testTrimRightSlashFromWebPathOnConstruct(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -96,7 +97,7 @@ public function testTrimRightSlashFromWebPathOnConstruct()
         $this->assertAttributeSame('aWebRoot', 'webRoot', $resolver);
     }
 
-    public function testRemoveDoubleSlashFromWebRootOnConstruct()
+    public function testRemoveDoubleSlashFromWebRootOnConstruct(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -108,7 +109,7 @@ public function testRemoveDoubleSlashFromWebRootOnConstruct()
         $this->assertAttributeSame('aWeb/Root', 'webRoot', $resolver);
     }
 
-    public function testTrimRightSlashFromCachePrefixOnConstruct()
+    public function testTrimRightSlashFromCachePrefixOnConstruct(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -120,7 +121,7 @@ public function testTrimRightSlashFromCachePrefixOnConstruct()
         $this->assertAttributeSame('aCachePrefix', 'cachePrefix', $resolver);
     }
 
-    public function testRemoveDoubleSlashFromCachePrefixOnConstruct()
+    public function testRemoveDoubleSlashFromCachePrefixOnConstruct(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -132,7 +133,7 @@ public function testRemoveDoubleSlashFromCachePrefixOnConstruct()
         $this->assertAttributeSame('aCache/Prefix', 'cachePrefix', $resolver);
     }
 
-    public function testReturnTrueIfFileExistsOnIsStored()
+    public function testReturnTrueIfFileExistsOnIsStored(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -144,7 +145,7 @@ public function testReturnTrueIfFileExistsOnIsStored()
         $this->assertTrue($resolver->isStored('existingPath', 'aFilter'));
     }
 
-    public function testReturnFalseIfFileNotExistsOnIsStored()
+    public function testReturnFalseIfFileNotExistsOnIsStored(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -156,7 +157,7 @@ public function testReturnFalseIfFileNotExistsOnIsStored()
         $this->assertFalse($resolver->isStored('nonExistingPath', 'aFilter'));
     }
 
-    public function testReturnFalseIfIsNotFile()
+    public function testReturnFalseIfIsNotFile(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -168,7 +169,7 @@ public function testReturnFalseIfIsNotFile()
         $this->assertFalse($resolver->isStored('', 'aFilter'));
     }
 
-    public function testComposeSchemaHostAndFileUrlOnResolve()
+    public function testComposeSchemaHostAndFileUrlOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('theSchema');
@@ -187,7 +188,7 @@ public function testComposeSchemaHostAndFileUrlOnResolve()
         );
     }
 
-    public function testComposeSchemaHostAndBasePathWithPhpFileAndFileUrlOnResolve()
+    public function testComposeSchemaHostAndBasePathWithPhpFileAndFileUrlOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('theSchema');
@@ -207,7 +208,7 @@ public function testComposeSchemaHostAndBasePathWithPhpFileAndFileUrlOnResolve()
         );
     }
 
-    public function testResolveWithPrefixCacheEmpty()
+    public function testResolveWithPrefixCacheEmpty(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('theSchema');
@@ -227,7 +228,7 @@ public function testResolveWithPrefixCacheEmpty()
         );
     }
 
-    public function testComposeSchemaHostAndBasePathWithDirsOnlyAndFileUrlOnResolve()
+    public function testComposeSchemaHostAndBasePathWithDirsOnlyAndFileUrlOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('theSchema');
@@ -247,7 +248,7 @@ public function testComposeSchemaHostAndBasePathWithDirsOnlyAndFileUrlOnResolve(
         );
     }
 
-    public function testComposeSchemaHostAndBasePathWithBackSplashOnResolve()
+    public function testComposeSchemaHostAndBasePathWithBackSplashOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('theSchema');
@@ -267,7 +268,7 @@ public function testComposeSchemaHostAndBasePathWithBackSplashOnResolve()
         );
     }
 
-    public function testComposeSchemaHttpAndCustomPortAndFileUrlOnResolve()
+    public function testComposeSchemaHttpAndCustomPortAndFileUrlOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('http');
@@ -287,7 +288,7 @@ public function testComposeSchemaHttpAndCustomPortAndFileUrlOnResolve()
         );
     }
 
-    public function testComposeSchemaHttpsAndCustomPortAndFileUrlOnResolve()
+    public function testComposeSchemaHttpsAndCustomPortAndFileUrlOnResolve(): void
     {
         $requestContext = new RequestContext();
         $requestContext->setScheme('https');
@@ -307,7 +308,7 @@ public function testComposeSchemaHttpsAndCustomPortAndFileUrlOnResolve()
         );
     }
 
-    public function testDumpBinaryContentOnStore()
+    public function testDumpBinaryContentOnStore(): void
     {
         $binary = new Binary('theContent', 'aMimeType', 'aFormat');
 
@@ -327,7 +328,7 @@ public function testDumpBinaryContentOnStore()
         $this->assertNull($resolver->store($binary, 'aPath', 'aFilter'));
     }
 
-    public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
+    public function testDoNothingIfFiltersAndPathsEmptyOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -344,7 +345,7 @@ public function testDoNothingIfFiltersAndPathsEmptyOnRemove()
         $resolver->remove([], []);
     }
 
-    public function testRemoveCacheForPathAndFilterOnRemove()
+    public function testRemoveCacheForPathAndFilterOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -362,7 +363,7 @@ public function testRemoveCacheForPathAndFilterOnRemove()
         $resolver->remove(['aPath'], ['aFilter']);
     }
 
-    public function testRemoveCacheForSomePathsAndFilterOnRemove()
+    public function testRemoveCacheForSomePathsAndFilterOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -384,7 +385,7 @@ public function testRemoveCacheForSomePathsAndFilterOnRemove()
         $resolver->remove(['aPathOne', 'aPathTwo'], ['aFilter']);
     }
 
-    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
+    public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -417,7 +418,7 @@ public function testRemoveCacheForSomePathsAndSomeFiltersOnRemove()
         );
     }
 
-    public function testRemoveCacheForFilterOnRemove()
+    public function testRemoveCacheForFilterOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -437,7 +438,7 @@ public function testRemoveCacheForFilterOnRemove()
         $resolver->remove([], ['aFilter']);
     }
 
-    public function testRemoveCacheForSomeFiltersOnRemove()
+    public function testRemoveCacheForSomeFiltersOnRemove(): void
     {
         $filesystemMock = $this->createFilesystemMock();
         $filesystemMock
@@ -458,7 +459,7 @@ public function testRemoveCacheForSomeFiltersOnRemove()
         $resolver->remove([], ['aFilterOne', 'aFilterTwo']);
     }
 
-    public function testShouldRemoveDoubleSlashInUrl()
+    public function testShouldRemoveDoubleSlashInUrl(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -476,7 +477,7 @@ public function testShouldRemoveDoubleSlashInUrl()
         $this->assertSame('aCachePrefix/some_filter/cats.jpg', $result);
     }
 
-    public function testShouldSanitizeSeparatorBetweenSchemeAndAuthorityInUrl()
+    public function testShouldSanitizeSeparatorBetweenSchemeAndAuthorityInUrl(): void
     {
         $resolver = new WebPathResolver(
             $this->createFilesystemMock(),
@@ -495,7 +496,7 @@ public function testShouldSanitizeSeparatorBetweenSchemeAndAuthorityInUrl()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|Filesystem
+     * @return MockObject|Filesystem
      */
     protected function createFilesystemMock()
     {
diff --git a/Tests/Imagine/Cache/SignerTest.php b/Tests/Imagine/Cache/SignerTest.php
index f2f7b8368..aca8ec265 100644
--- a/Tests/Imagine/Cache/SignerTest.php
+++ b/Tests/Imagine/Cache/SignerTest.php
@@ -20,42 +20,42 @@
  */
 class SignerTest extends AbstractTest
 {
-    public function testImplementsSignerInterface()
+    public function testImplementsSignerInterface(): void
     {
         $rc = new \ReflectionClass(Signer::class);
 
         $this->assertTrue($rc->implementsInterface(SignerInterface::class));
     }
 
-    public function testCouldBeConstructedWithSecret()
+    public function testCouldBeConstructedWithSecret(): void
     {
         $signer = new Signer('aSecret');
 
         $this->assertInstanceOf(Signer::class, $signer);
     }
 
-    public function testShouldReturnShortHashOnSign()
+    public function testShouldReturnShortHashOnSign(): void
     {
         $singer = new Signer('aSecret');
 
         $this->assertSame(8, mb_strlen($singer->sign('aPath')));
     }
 
-    public function testShouldSingAndSuccessfullyCheckPathWithoutRuntimeConfig()
+    public function testShouldSingAndSuccessfullyCheckPathWithoutRuntimeConfig(): void
     {
         $singer = new Signer('aSecret');
 
         $this->assertTrue($singer->check($singer->sign('aPath'), 'aPath'));
     }
 
-    public function testShouldSingAndSuccessfullyCheckPathWithRuntimeConfig()
+    public function testShouldSingAndSuccessfullyCheckPathWithRuntimeConfig(): void
     {
         $singer = new Signer('aSecret');
 
         $this->assertTrue($singer->check($singer->sign('aPath', ['aConfig']), 'aPath', ['aConfig']));
     }
 
-    public function testShouldConvertRecursivelyToStringAllRuntimeConfigParameters()
+    public function testShouldConvertRecursivelyToStringAllRuntimeConfigParameters(): void
     {
         $singer = new Signer('aSecret');
 
diff --git a/Tests/Imagine/Data/DataManagerTest.php b/Tests/Imagine/Data/DataManagerTest.php
index 320b32e08..df4d42372 100644
--- a/Tests/Imagine/Data/DataManagerTest.php
+++ b/Tests/Imagine/Data/DataManagerTest.php
@@ -11,7 +11,6 @@
 
 namespace Liip\ImagineBundle\Tests\Imagine\Data;
 
-use Liip\ImagineBundle\Binary\Loader\FlysystemLoader;
 use Liip\ImagineBundle\Imagine\Data\DataManager;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
@@ -22,7 +21,7 @@
  */
 class DataManagerTest extends AbstractTest
 {
-    public function testThrowsIfConstructedWithWrongTypeArguments()
+    public function testThrowsIfConstructedWithWrongTypeArguments(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('$extensionGuesser must be an instance of Symfony\Component\Mime\MimeTypesInterface or Symfony\Component\HttpFoundation\File\MimeType\ExtensionGuesserInterface');
@@ -33,7 +32,7 @@ public function testThrowsIfConstructedWithWrongTypeArguments()
         new DataManager($mimeTypeGuesser, 'foo', $config, 'default');
     }
 
-    public function testUseDefaultLoaderUsedIfNoneSet()
+    public function testUseDefaultLoaderUsedIfNoneSet(): void
     {
         $loader = $this->createBinaryLoaderInterfaceMock();
         $loader
@@ -64,7 +63,7 @@ public function testUseDefaultLoaderUsedIfNoneSet()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testUseLoaderRegisteredForFilterOnFind()
+    public function testUseLoaderRegisteredForFilterOnFind(): void
     {
         $loader = $this->createBinaryLoaderInterfaceMock();
         $loader
@@ -95,7 +94,7 @@ public function testUseLoaderRegisteredForFilterOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testThrowsIfMimeTypeWasNotGuessedOnFind()
+    public function testThrowsIfMimeTypeWasNotGuessedOnFind(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('The mime type of image cats.jpeg was not guessed');
@@ -128,7 +127,7 @@ public function testThrowsIfMimeTypeWasNotGuessedOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testThrowsIfMimeTypeNotImageOneOnFind()
+    public function testThrowsIfMimeTypeNotImageOneOnFind(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('The mime type of image cats.jpeg must be image/xxx got text/plain');
@@ -162,7 +161,7 @@ public function testThrowsIfMimeTypeNotImageOneOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testThrowsIfLoaderReturnBinaryWithEmtptyMimeTypeOnFind()
+    public function testThrowsIfLoaderReturnBinaryWithEmtptyMimeTypeOnFind(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('The mime type of image cats.jpeg was not guessed');
@@ -195,7 +194,7 @@ public function testThrowsIfLoaderReturnBinaryWithEmtptyMimeTypeOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testThrowsIfLoaderReturnBinaryWithMimeTypeNotImageOneOnFind()
+    public function testThrowsIfLoaderReturnBinaryWithMimeTypeNotImageOneOnFind(): void
     {
         $this->expectException(\LogicException::class);
         $this->expectExceptionMessage('The mime type of image cats.jpeg must be image/xxx got text/plain');
@@ -230,7 +229,7 @@ public function testThrowsIfLoaderReturnBinaryWithMimeTypeNotImageOneOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testThrowIfLoaderNotRegisteredForGivenFilterOnFind()
+    public function testThrowIfLoaderNotRegisteredForGivenFilterOnFind(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('Could not find data loader "" for "thumbnail" filter type');
@@ -250,7 +249,7 @@ public function testThrowIfLoaderNotRegisteredForGivenFilterOnFind()
         $dataManager->find('thumbnail', 'cats.jpeg');
     }
 
-    public function testShouldReturnBinaryWithLoaderContentAndGuessedMimeTypeOnFind()
+    public function testShouldReturnBinaryWithLoaderContentAndGuessedMimeTypeOnFind(): void
     {
         $expectedContent = 'theImageBinaryContent';
         $expectedMimeType = 'image/png';
@@ -289,7 +288,7 @@ public function testShouldReturnBinaryWithLoaderContentAndGuessedMimeTypeOnFind(
         $this->assertSame($expectedMimeType, $binary->getMimeType());
     }
 
-    public function testShouldReturnBinaryWithLoaderContentAndGuessedFormatOnFind()
+    public function testShouldReturnBinaryWithLoaderContentAndGuessedFormatOnFind(): void
     {
         $content = 'theImageBinaryContent';
         $mimeType = 'image/png';
@@ -344,7 +343,7 @@ public function testShouldReturnBinaryWithLoaderContentAndGuessedFormatOnFind()
         $this->assertSame($expectedFormat, $binary->getFormat());
     }
 
-    public function testUseDefaultGlobalImageUsedIfImageNotFound()
+    public function testUseDefaultGlobalImageUsedIfImageNotFound(): void
     {
         $loader = $this->createBinaryLoaderInterfaceMock();
 
@@ -370,7 +369,7 @@ public function testUseDefaultGlobalImageUsedIfImageNotFound()
         $this->assertSame($defaultImage, $defaultGlobalImage);
     }
 
-    public function testUseDefaultFilterImageUsedIfImageNotFound()
+    public function testUseDefaultFilterImageUsedIfImageNotFound(): void
     {
         $loader = $this->createBinaryLoaderInterfaceMock();
 
diff --git a/Tests/Imagine/Filter/FilterConfigurationTest.php b/Tests/Imagine/Filter/FilterConfigurationTest.php
index c4d9ca755..9ab8fcd58 100644
--- a/Tests/Imagine/Filter/FilterConfigurationTest.php
+++ b/Tests/Imagine/Filter/FilterConfigurationTest.php
@@ -19,7 +19,7 @@
  */
 class FilterConfigurationTest extends AbstractTest
 {
-    public function testSetAndGetFilter()
+    public function testSetAndGetFilter(): void
     {
         $config = [
             'filters' => [
@@ -37,7 +37,7 @@ public function testSetAndGetFilter()
         $this->assertSame($config, $filterConfiguration->get('profile_photo'));
     }
 
-    public function testReturnAllFilters()
+    public function testReturnAllFilters(): void
     {
         $filterConfiguration = new FilterConfiguration();
         $filterConfiguration->set('foo', ['fooConfig']);
@@ -45,7 +45,7 @@ public function testReturnAllFilters()
 
         $filters = $filterConfiguration->all();
 
-        $this->assertInternalType('array', $filters);
+        $this->assertIsArray($filters);
 
         $this->assertArrayHasKey('foo', $filters);
         $this->assertSame(['fooConfig'], $filters['foo']);
@@ -54,7 +54,7 @@ public function testReturnAllFilters()
         $this->assertSame(['barConfig'], $filters['bar']);
     }
 
-    public function testGetUndefinedFilter()
+    public function testGetUndefinedFilter(): void
     {
         $this->expectException(\RuntimeException::class);
         $this->expectExceptionMessage('Could not find configuration for a filter: thumbnail');
@@ -63,7 +63,7 @@ public function testGetUndefinedFilter()
         $filterConfiguration->get('thumbnail');
     }
 
-    public function testShouldGetSameConfigSetBefore()
+    public function testShouldGetSameConfigSetBefore(): void
     {
         $config = [
             'quality' => 85,
@@ -83,14 +83,14 @@ public function testShouldGetSameConfigSetBefore()
         $this->assertSame($config, $filterConfiguration->get('profile_photo'));
     }
 
-    public function testGetConfigSetViaConstructor()
+    public function testGetConfigSetViaConstructor(): void
     {
         $filterConfiguration = new FilterConfiguration([
             'profile_photo' => [],
             'thumbnail' => [],
         ]);
 
-        $this->assertInternalType('array', $filterConfiguration->get('profile_photo'));
-        $this->assertInternalType('array', $filterConfiguration->get('thumbnail'));
+        $this->assertIsArray($filterConfiguration->get('profile_photo'));
+        $this->assertIsArray($filterConfiguration->get('thumbnail'));
     }
 }
diff --git a/Tests/Imagine/Filter/FilterManagerTest.php b/Tests/Imagine/Filter/FilterManagerTest.php
index 608c91d2d..257bae1d9 100644
--- a/Tests/Imagine/Filter/FilterManagerTest.php
+++ b/Tests/Imagine/Filter/FilterManagerTest.php
@@ -16,13 +16,14 @@
 use Liip\ImagineBundle\Imagine\Filter\Loader\LoaderInterface;
 use Liip\ImagineBundle\Model\Binary;
 use Liip\ImagineBundle\Tests\AbstractTest;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @covers \Liip\ImagineBundle\Imagine\Filter\FilterManager
  */
 class FilterManagerTest extends AbstractTest
 {
-    public function testThrowsIfNoLoadersAddedForFilterOnApplyFilter()
+    public function testThrowsIfNoLoadersAddedForFilterOnApplyFilter(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('Could not find filter(s): "thumbnail"');
@@ -53,7 +54,7 @@ public function testThrowsIfNoLoadersAddedForFilterOnApplyFilter()
         $filterManager->applyFilter($binary, 'thumbnail');
     }
 
-    public function testReturnFilteredBinaryWithExpectedContentOnApplyFilter()
+    public function testReturnFilteredBinaryWithExpectedContentOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedFilteredContent = 'theFilteredContent';
@@ -110,7 +111,7 @@ public function testReturnFilteredBinaryWithExpectedContentOnApplyFilter()
         $this->assertSame($expectedFilteredContent, $filteredBinary->getContent());
     }
 
-    public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApplyFilter()
+    public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedFormat = 'png';
@@ -166,7 +167,7 @@ public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApplyFilter(
         $this->assertSame($expectedFormat, $filteredBinary->getFormat());
     }
 
-    public function testReturnFilteredBinaryWithCustomFormatIfSetOnApplyFilter()
+    public function testReturnFilteredBinaryWithCustomFormatIfSetOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $originalFormat = 'png';
@@ -224,7 +225,7 @@ public function testReturnFilteredBinaryWithCustomFormatIfSetOnApplyFilter()
         $this->assertSame($expectedFormat, $filteredBinary->getFormat());
     }
 
-    public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApplyFilter()
+    public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedMimeType = 'image/png';
@@ -285,7 +286,7 @@ public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApplyFilte
         $this->assertSame($expectedMimeType, $filteredBinary->getMimeType());
     }
 
-    public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApplyFilter()
+    public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $originalMimeType = 'image/png';
@@ -351,7 +352,7 @@ public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApplyFi
         $this->assertSame($expectedMimeType, $filteredBinary->getMimeType());
     }
 
-    public function testAltersQualityOnApplyFilter()
+    public function testAltersQualityOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedQuality = 80;
@@ -406,7 +407,7 @@ public function testAltersQualityOnApplyFilter()
         $this->assertInstanceOf(Binary::class, $filterManager->applyFilter($binary, 'thumbnail'));
     }
 
-    public function testAlters100QualityIfNotSetOnApplyFilter()
+    public function testAlters100QualityIfNotSetOnApplyFilter(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedQuality = 100;
@@ -460,7 +461,7 @@ public function testAlters100QualityIfNotSetOnApplyFilter()
         $this->assertInstanceOf(Binary::class, $filterManager->applyFilter($binary, 'thumbnail'));
     }
 
-    public function testMergeRuntimeConfigWithOneFromFilterConfigurationOnApplyFilter()
+    public function testMergeRuntimeConfigWithOneFromFilterConfigurationOnApplyFilter(): void
     {
         $binary = new Binary('aContent', 'image/png', 'png');
 
@@ -527,7 +528,7 @@ public function testMergeRuntimeConfigWithOneFromFilterConfigurationOnApplyFilte
         );
     }
 
-    public function testThrowsIfNoLoadersAddedForFilterOnApply()
+    public function testThrowsIfNoLoadersAddedForFilterOnApply(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('Could not find filter(s): "thumbnail"');
@@ -550,7 +551,7 @@ public function testThrowsIfNoLoadersAddedForFilterOnApply()
         ]);
     }
 
-    public function testReturnFilteredBinaryWithExpectedContentOnApply()
+    public function testReturnFilteredBinaryWithExpectedContentOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedFilteredContent = 'theFilteredContent';
@@ -600,7 +601,7 @@ public function testReturnFilteredBinaryWithExpectedContentOnApply()
         $this->assertSame($expectedFilteredContent, $filteredBinary->getContent());
     }
 
-    public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApply()
+    public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedFormat = 'png';
@@ -649,7 +650,7 @@ public function testReturnFilteredBinaryWithFormatOfOriginalBinaryOnApply()
         $this->assertSame($expectedFormat, $filteredBinary->getFormat());
     }
 
-    public function testReturnFilteredBinaryWithCustomFormatIfSetOnApply()
+    public function testReturnFilteredBinaryWithCustomFormatIfSetOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $originalFormat = 'png';
@@ -700,7 +701,7 @@ public function testReturnFilteredBinaryWithCustomFormatIfSetOnApply()
         $this->assertSame($expectedFormat, $filteredBinary->getFormat());
     }
 
-    public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApply()
+    public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedMimeType = 'image/png';
@@ -754,7 +755,7 @@ public function testReturnFilteredBinaryWithMimeTypeOfOriginalBinaryOnApply()
         $this->assertSame($expectedMimeType, $filteredBinary->getMimeType());
     }
 
-    public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApply()
+    public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $originalMimeType = 'image/png';
@@ -813,7 +814,7 @@ public function testReturnFilteredBinaryWithMimeTypeOfCustomFormatIfSetOnApply()
         $this->assertSame($expectedMimeType, $filteredBinary->getMimeType());
     }
 
-    public function testAltersQualityOnApply()
+    public function testAltersQualityOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedQuality = 80;
@@ -863,7 +864,7 @@ public function testAltersQualityOnApply()
         $this->assertInstanceOf(Binary::class, $filteredBinary);
     }
 
-    public function testAlters100QualityIfNotSetOnApply()
+    public function testAlters100QualityIfNotSetOnApply(): void
     {
         $originalContent = 'aOriginalContent';
         $expectedQuality = 100;
@@ -912,7 +913,7 @@ public function testAlters100QualityIfNotSetOnApply()
         $this->assertInstanceOf(Binary::class, $filteredBinary);
     }
 
-    public function testApplyPostProcessor()
+    public function testApplyPostProcessor(): void
     {
         $originalContent = 'aContent';
         $expectedPostProcessedContent = 'postProcessedContent';
@@ -984,7 +985,7 @@ public function testApplyPostProcessor()
         $this->assertSame($expectedPostProcessedContent, $filteredBinary->getContent());
     }
 
-    public function testThrowsIfNoPostProcessorAddedForFilterOnApplyFilter()
+    public function testThrowsIfNoPostProcessorAddedForFilterOnApplyFilter(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->expectExceptionMessage('Could not find post processor(s): "foo"');
@@ -1046,7 +1047,7 @@ public function testThrowsIfNoPostProcessorAddedForFilterOnApplyFilter()
         $filterManager->applyFilter($binary, 'thumbnail');
     }
 
-    public function testApplyPostProcessorsWhenNotDefined()
+    public function testApplyPostProcessorsWhenNotDefined(): void
     {
         $binary = $this->getMockBuilder(BinaryInterface::class)->getMock();
         $filterManager = new FilterManager(
@@ -1059,7 +1060,7 @@ public function testApplyPostProcessorsWhenNotDefined()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|LoaderInterface
+     * @return MockObject|LoaderInterface
      */
     protected function createFilterLoaderInterfaceMock()
     {
diff --git a/Tests/Imagine/Filter/Loader/AutoRotateFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/AutoRotateFilterLoaderTest.php
index 7b1ca5b0a..f1187cb0d 100644
--- a/Tests/Imagine/Filter/Loader/AutoRotateFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/AutoRotateFilterLoaderTest.php
@@ -25,10 +25,8 @@ public function testUseAutorotateFromImagine(): void
 
         $image = $this->getImageInterfaceMock();
         $image->expects($this->once())
-            ->method('metadata')
-        ;
+            ->method('metadata');
 
         $loader->load($image);
-
     }
 }
diff --git a/Tests/Imagine/Filter/Loader/CropFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/CropFilterLoaderTest.php
index b949e1729..716181e76 100644
--- a/Tests/Imagine/Filter/Loader/CropFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/CropFilterLoaderTest.php
@@ -31,7 +31,7 @@ class CropFilterLoaderTest extends AbstractTest
      *
      * @dataProvider cropDataProvider
      */
-    public function testLoad($coordinates, $area)
+    public function testLoad(array $coordinates, array $area): void
     {
         $x = $coordinates[0];
         $y = $coordinates[1];
@@ -57,7 +57,7 @@ public function testLoad($coordinates, $area)
     /**
      * @returns array Array containing coordinate and width/height pairs.
      */
-    public function cropDataProvider()
+    public function cropDataProvider(): array
     {
         return [
             [[140, 130], [200, 129]],
diff --git a/Tests/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
index 3dcd610e6..f4cd6e3b7 100644
--- a/Tests/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/DownscaleFilterLoaderTest.php
@@ -28,7 +28,7 @@ class DownscaleFilterLoaderTest extends AbstractTest
      * @param Box $resultSize
      * @param Box $initialSize
      */
-    public function testDontScaleUp($resultSize, $initialSize)
+    public function testDontScaleUp($resultSize, $initialSize): void
     {
         $this->assertLessThanOrEqual($initialSize->getHeight(), $resultSize->getHeight());
         $this->assertLessThanOrEqual($initialSize->getWidth(), $resultSize->getWidth());
@@ -39,7 +39,7 @@ public function testDontScaleUp($resultSize, $initialSize)
      *
      * @param Box $resultSize
      */
-    public function testFitBoundingBox($resultSize)
+    public function testFitBoundingBox($resultSize): void
     {
         $this->assertLessThanOrEqual(100, $resultSize->getHeight());
         $this->assertLessThanOrEqual(90, $resultSize->getWidth());
diff --git a/Tests/Imagine/Filter/Loader/FixedFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/FixedFilterLoaderTest.php
index 9fc1f8c0f..bd4e083ca 100644
--- a/Tests/Imagine/Filter/Loader/FixedFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/FixedFilterLoaderTest.php
@@ -32,15 +32,11 @@ class FixedFilterLoaderTest extends AbstractTest
     const DUMMY_IMAGE_HEIGHT = 600;
 
     /**
-     * @param int $width
-     * @param int $height
-     * @param Box $expected
-     *
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\FixedFilterLoader::load
      *
      * @dataProvider heightWidthProvider
      */
-    public function testLoad($width, $height, $expected)
+    public function testLoad(int $width, int $height, Box $expected): void
     {
         $loader = new FixedFilterLoader();
 
@@ -74,13 +70,10 @@ public function testLoad($width, $height, $expected)
         $options['width'] = $width;
         $options['height'] = $height;
 
-        $result = $loader->load($image, $options);
+        $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing width/height pairs and an expected size.
-     */
-    public function heightWidthProvider()
+    public function heightWidthProvider(): array
     {
         return [
             [200, 129, new Box(200, 129)],
diff --git a/Tests/Imagine/Filter/Loader/FlipFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/FlipFilterLoaderTest.php
index cd1b8574c..93b7c6e7d 100644
--- a/Tests/Imagine/Filter/Loader/FlipFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/FlipFilterLoaderTest.php
@@ -19,10 +19,7 @@
  */
 class FlipFilterLoaderTest extends AbstractTest
 {
-    /**
-     * @return array
-     */
-    public static function provideLoadWithAxisXOptionData()
+    public static function provideLoadWithAxisXOptionData(): array
     {
         return [
             ['x'],
@@ -31,11 +28,9 @@ public static function provideLoadWithAxisXOptionData()
     }
 
     /**
-     * @param string $axis
-     *
      * @dataProvider provideLoadWithAxisXOptionData
      */
-    public function testLoadWithAxisXOption($axis)
+    public function testLoadWithAxisXOption(string $axis): void
     {
         $image = $this->getImageInterfaceMock();
         $image->expects($this->once())
@@ -45,10 +40,7 @@ public function testLoadWithAxisXOption($axis)
         $this->createFlipFilterLoaderInstance()->load($image, ['axis' => $axis]);
     }
 
-    /**
-     * @return array
-     */
-    public static function provideLoadWithAxisYOptionData()
+    public static function provideLoadWithAxisYOptionData(): array
     {
         return [
             ['y'],
@@ -57,11 +49,9 @@ public static function provideLoadWithAxisYOptionData()
     }
 
     /**
-     * @param string $axis
-     *
      * @dataProvider provideLoadWithAxisYOptionData
      */
-    public function testLoadWithAxisYOption($axis)
+    public function testLoadWithAxisYOption(string $axis): void
     {
         $image = $this->getImageInterfaceMock();
         $image->expects($this->once())
@@ -71,7 +61,7 @@ public function testLoadWithAxisYOption($axis)
         $this->createFlipFilterLoaderInstance()->load($image, ['axis' => $axis]);
     }
 
-    public function testThrowsOnInvalidOptions()
+    public function testThrowsOnInvalidOptions(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('The "axis" option must be set to "x", "horizontal", "y", or "vertical".');
@@ -82,10 +72,7 @@ public function testThrowsOnInvalidOptions()
         ]);
     }
 
-    /**
-     * @return FlipFilterLoader
-     */
-    private function createFlipFilterLoaderInstance()
+    private function createFlipFilterLoaderInstance(): FlipFilterLoader
     {
         return new FlipFilterLoader();
     }
diff --git a/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundDownscaleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundDownscaleFilterLoaderTest.php
index 14798c627..aeaed327b 100644
--- a/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundDownscaleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundDownscaleFilterLoaderTest.php
@@ -24,7 +24,7 @@
  */
 class FloatToIntCastByRoundDownscaleFilterLoaderTest extends AbstractTest
 {
-    public function testLoad()
+    public function testLoad(): void
     {
         $loader = new DownscaleFilterLoader();
         $imagine = new Imagine();
diff --git a/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundUpscaleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundUpscaleFilterLoaderTest.php
index ebfb568ff..fdbd41756 100644
--- a/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundUpscaleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/FloatToIntCastByRoundUpscaleFilterLoaderTest.php
@@ -24,7 +24,7 @@
  */
 class FloatToIntCastByRoundUpscaleFilterLoaderTest extends AbstractTest
 {
-    public function testLoad()
+    public function testLoad(): void
     {
         $loader = new UpscaleFilterLoader();
         $imagine = new Imagine();
diff --git a/Tests/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
index 143851819..3f9036538 100644
--- a/Tests/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/GrayscaleFilterLoaderTest.php
@@ -25,7 +25,7 @@
  */
 class GrayscaleFilterLoaderTest extends AbstractTest
 {
-    public function testLoadGrayscale()
+    public function testLoadGrayscale(): void
     {
         $loader = new GrayscaleFilterLoader();
         $palette = new RGB();
diff --git a/Tests/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
index 94f63f728..c734c1131 100644
--- a/Tests/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/InterlaceFilterLoaderTest.php
@@ -20,7 +20,7 @@
  */
 class InterlaceFilterLoaderTest extends AbstractTest
 {
-    public function testLoad()
+    public function testLoad(): void
     {
         $loader = new InterlaceFilterLoader();
 
diff --git a/Tests/Imagine/Filter/Loader/PasteFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/PasteFilterLoaderTest.php
index 5355e30ed..202c3fc9a 100644
--- a/Tests/Imagine/Filter/Loader/PasteFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/PasteFilterLoaderTest.php
@@ -34,15 +34,11 @@ class PasteFilterLoaderTest extends AbstractTest
     const DUMMY_IMAGE_HEIGHT = 600;
 
     /**
-     * @param int   $x
-     * @param int   $y
-     * @param Point $expected
-     *
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\PasteFilterLoader::load
      *
      * @dataProvider pasteProvider
      */
-    public function testLoad($x, $y, $expected)
+    public function testLoad(int $x, int $y, Point $expected): void
     {
         $mockImageSize = new Box(
             self::DUMMY_IMAGE_WIDTH,
@@ -69,10 +65,7 @@ public function testLoad($x, $y, $expected)
         $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing coordinates to paste.
-     */
-    public function pasteProvider()
+    public function pasteProvider(): array
     {
         return [
             [200, 129, new Point(200, 129)],
diff --git a/Tests/Imagine/Filter/Loader/ResampleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
index 47b134e54..c82146e93 100644
--- a/Tests/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/ResampleFilterLoaderTest.php
@@ -28,7 +28,7 @@ class ResampleFilterLoaderTest extends AbstractTest
      * @param string $imgPath
      * @param float  $resolution
      */
-    public function testResample($imgPath, $resolution)
+    public function testResample($imgPath, $resolution): void
     {
         $imgType = static::getSupportedDriver();
         $tmpPath = sys_get_temp_dir().DIRECTORY_SEPARATOR.sprintf('liip-imagine-bundle-test-%s-%d.%s', md5($imgPath), time(), pathinfo($imgPath, PATHINFO_EXTENSION));
@@ -50,7 +50,7 @@ public function testResample($imgPath, $resolution)
     /**
      * @return array[]
      */
-    public static function provideResampleData()
+    public static function provideResampleData(): array
     {
         $paths = [
             realpath(__DIR__.'/../../../Fixtures/assets/cats.png'),
@@ -73,10 +73,7 @@ public static function provideResampleData()
         return $data;
     }
 
-    /**
-     * @return array
-     */
-    public static function provideOptionsData()
+    public static function provideOptionsData(): array
     {
         return [
             [['x' => 500, 'y' => 500, 'unit' => 'ppi']],
@@ -89,11 +86,9 @@ public static function provideOptionsData()
     }
 
     /**
-     * @param array $options
-     *
      * @dataProvider provideOptionsData
      */
-    public function testOptions(array $options)
+    public function testOptions(array $options): void
     {
         $image = $this->getImageInterfaceMock();
         $image->expects($this->once())
@@ -108,10 +103,7 @@ public function testOptions(array $options)
         $this->createResampleFilterLoaderInstance($imagine)->load($image, $options);
     }
 
-    /**
-     * @return array
-     */
-    public static function provideInvalidOptionsData()
+    public static function provideInvalidOptionsData(): array
     {
         return [
             [[]],
@@ -136,7 +128,7 @@ public static function provideInvalidOptionsData()
     /**
      * @dataProvider provideInvalidOptionsData
      */
-    public function testThrowsOnInvalidOptions(array $options)
+    public function testThrowsOnInvalidOptions(array $options): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('Invalid option(s) passed to Liip\\ImagineBundle\\Imagine\\Filter\\Loader\\ResampleFilterLoader::load().');
@@ -145,7 +137,7 @@ public function testThrowsOnInvalidOptions(array $options)
         $loader->load($this->getImageInterfaceMock(), $options);
     }
 
-    public function testThrowsOnInvalidFilterOption()
+    public function testThrowsOnInvalidFilterOption(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\InvalidArgumentException::class);
         $this->expectExceptionMessage('Invalid value for "filter" option: must be a valid constant resolvable using one of formats "\\Imagine\\Image\\ImageInterface::FILTER_%s", "\\Imagine\\Image\\ImageInterface::%s", or "%s".');
@@ -159,7 +151,7 @@ public function testThrowsOnInvalidFilterOption()
         ]);
     }
 
-    public function testThrowsOnInvalidTemporaryPathOption()
+    public function testThrowsOnInvalidTemporaryPathOption(): void
     {
         $this->expectException(\RuntimeException::class);
         $this->expectExceptionMessageRegExp('{Unable to create temporary file in ".+" base path.}');
@@ -173,7 +165,7 @@ public function testThrowsOnInvalidTemporaryPathOption()
         ]);
     }
 
-    public function testThrowsOnSaveOrOpenError()
+    public function testThrowsOnSaveOrOpenError(): void
     {
         $this->expectException(\Liip\ImagineBundle\Exception\Imagine\Filter\LoadFilterException::class);
 
@@ -185,24 +177,18 @@ public function testThrowsOnSaveOrOpenError()
         $this->createResampleFilterLoaderInstance()->load($image, ['x' => 120, 'y' => 120, 'unit' => 'ppi']);
     }
 
-    /**
-     * @param ImagineInterface $imagine
-     *
-     * @return ResampleFilterLoader
-     */
-    private function createResampleFilterLoaderInstance(ImagineInterface $imagine = null)
+    private function createResampleFilterLoaderInstance(ImagineInterface $imagine = null): ResampleFilterLoader
     {
         return new ResampleFilterLoader($imagine ?: $this->createImagineInterfaceMock());
     }
 
-    /**
-     * @return string
-     */
-    private static function getSupportedDriver()
+    private static function getSupportedDriver(): string
     {
-        if (class_exists('\Imagick')) {
+        if (class_exists(\Imagick::class)) {
             return 'imagick';
-        } elseif (class_exists('\Gmagick')) {
+        }
+
+        if (class_exists(\Gmagick::class)) {
             return 'gmagick';
         }
 
@@ -224,13 +210,7 @@ private function getImagineInstance($driver)
         }
     }
 
-    /**
-     * @param string $driver
-     * @param string $file
-     *
-     * @return float[]
-     */
-    private function getImageResolution($driver, $file)
+    private function getImageResolution(string $driver, string $file): array
     {
         switch ($driver) {
             case 'imagick':
diff --git a/Tests/Imagine/Filter/Loader/ResizeFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/ResizeFilterLoaderTest.php
index f2c511228..4a1496a4d 100644
--- a/Tests/Imagine/Filter/Loader/ResizeFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/ResizeFilterLoaderTest.php
@@ -23,14 +23,11 @@
 class ResizeFilterLoaderTest extends AbstractTest
 {
     /**
-     * @param int $width
-     * @param int $height
-     *
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\ResizeFilterLoader::load
      *
      * @dataProvider resizeDataProvider
      */
-    public function testLoad($width, $height)
+    public function testLoad(int $width, int $height): void
     {
         $loader = new ResizeFilterLoader();
 
@@ -46,10 +43,7 @@ public function testLoad($width, $height)
         $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing width/height pairs.
-     */
-    public function resizeDataProvider()
+    public function resizeDataProvider(): array
     {
         return [
             [140, 130],
diff --git a/Tests/Imagine/Filter/Loader/RotateFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/RotateFilterLoaderTest.php
index 472b74af5..6917cadf2 100644
--- a/Tests/Imagine/Filter/Loader/RotateFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/RotateFilterLoaderTest.php
@@ -21,7 +21,7 @@
  */
 class RotateFilterLoaderTest extends AbstractTest
 {
-    public function testLoadRotate0Degrees()
+    public function testLoadRotate0Degrees(): void
     {
         $loader = new RotateFilterLoader();
 
@@ -31,7 +31,7 @@ public function testLoadRotate0Degrees()
         $this->assertSame($image, $result);
     }
 
-    public function testLoadRotate90Degrees()
+    public function testLoadRotate90Degrees(): void
     {
         $loader = new RotateFilterLoader();
 
diff --git a/Tests/Imagine/Filter/Loader/ScaleFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/ScaleFilterLoaderTest.php
index 043e48249..ec2cd5836 100644
--- a/Tests/Imagine/Filter/Loader/ScaleFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/ScaleFilterLoaderTest.php
@@ -46,7 +46,7 @@ class ScaleFilterLoaderTest extends AbstractTest
     /**
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\ScaleFilterLoader::load
      */
-    public function testItShouldPreserveRatio()
+    public function testItShouldPreserveRatio(): void
     {
         $loader = new ScaleFilterLoader();
         $image = $this->getImageInterfaceMock();
@@ -71,7 +71,7 @@ public function testItShouldPreserveRatio()
      * @param int[] $dimensions
      * @param Box   $expected
      */
-    public function testItShouldUseDimensions($dimensions, $expected)
+    public function testItShouldUseDimensions($dimensions, $expected): void
     {
         $loader = new ScaleFilterLoader();
 
@@ -91,7 +91,7 @@ public function testItShouldUseDimensions($dimensions, $expected)
     /**
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\ScaleFilterLoader::load
      */
-    public function itShouldThrowInvalidArgumentException()
+    public function itShouldThrowInvalidArgumentException(): void
     {
         $this->expectException(\InvalidArgumentException::class);
 
@@ -99,10 +99,7 @@ public function itShouldThrowInvalidArgumentException()
         $scale->load($this->getImageInterfaceMock(), []);
     }
 
-    /**
-     * @returns array Array containing coordinate and width/height pairs.
-     */
-    public function dimensionsDataProvider()
+    public function dimensionsDataProvider(): array
     {
         return [
             [[150, 150], new Box(125, 150)],
@@ -117,7 +114,7 @@ public function dimensionsDataProvider()
      * @param int[] $dimensions
      * @param Box   $expected
      */
-    public function testShouldScale($dimensions, $expected)
+    public function testShouldScale($dimensions, $expected): void
     {
         $loader = new UpscaleFilterLoader();
         $image = $this->getUpscaleMockImage();
@@ -133,10 +130,7 @@ public function testShouldScale($dimensions, $expected)
         $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing coordinate and width/height pairs.
-     */
-    public function minScaleDataProvider()
+    public function minScaleDataProvider(): array
     {
         return [
             [[1000, 600], new Box(1000, 667)],
@@ -150,7 +144,7 @@ public function minScaleDataProvider()
      * @param int[] $dimensions
      * @param Box   $expected
      */
-    public function testShouldNotScale($dimensions, $expected)
+    public function testShouldNotScale($dimensions, $expected): void
     {
         $loader = new UpscaleFilterLoader();
         $image = $this->getUpscaleMockImage();
@@ -166,10 +160,7 @@ public function testShouldNotScale($dimensions, $expected)
         $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing coordinate and width/height pairs.
-     */
-    public function minNotScaleDataProvider()
+    public function minNotScaleDataProvider(): array
     {
         return [
             [[300, 200], new Box(600, 400)],
diff --git a/Tests/Imagine/Filter/Loader/ThumbnailFilterLoaderTest.php b/Tests/Imagine/Filter/Loader/ThumbnailFilterLoaderTest.php
index 5dbe0daa5..7305ce7fc 100644
--- a/Tests/Imagine/Filter/Loader/ThumbnailFilterLoaderTest.php
+++ b/Tests/Imagine/Filter/Loader/ThumbnailFilterLoaderTest.php
@@ -33,15 +33,11 @@ class ThumbnailFilterLoaderTest extends AbstractTest
     const DUMMY_IMAGE_HEIGHT = 600;
 
     /**
-     * @param int $width
-     * @param int $height
-     * @param Box $expected
-     *
      * @covers \Liip\ImagineBundle\Imagine\Filter\Loader\ThumbnailFilterLoader::load
      *
      * @dataProvider heightWidthProvider
      */
-    public function testLoad($width, $height, $expected)
+    public function testLoad(?int $width, ?int $height, Box $expected): void
     {
         $loader = new ThumbnailFilterLoader();
 
@@ -64,10 +60,7 @@ public function testLoad($width, $height, $expected)
         $loader->load($image, $options);
     }
 
-    /**
-     * @returns array Array containing width/height pairs and an expected size.
-     */
-    public function heightWidthProvider()
+    public function heightWidthProvider(): array
     {
         return [
             [200, 129, new Box(200, 129)],
diff --git a/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTest.php b/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTest.php
index 32ecfbde3..545c0a6c2 100644
--- a/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTest.php
+++ b/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTest.php
@@ -139,12 +139,10 @@ public function testIsValidReturn(array $validReturns, array $errorString, bool
             ->getMock();
 
         $process
-            ->expects($this->any())
             ->method('getExitCode')
             ->willReturn(0);
 
         $process
-            ->expects($this->any())
             ->method('getOutput')
             ->willReturn('foo bar baz');
 
@@ -157,7 +155,7 @@ public function testIsValidReturn(array $validReturns, array $errorString, bool
 
     protected function getPostProcessorInstance(array $parameters = []): PostProcessorInterface
     {
-        if (0 === count($parameters)) {
+        if (0 === \count($parameters)) {
             $parameters = [static::getPostProcessAsStdInExecutable()];
         }
 
diff --git a/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTestCase.php b/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTestCase.php
index e8ee715d4..414f600ab 100644
--- a/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTestCase.php
+++ b/Tests/Imagine/Filter/PostProcessor/AbstractPostProcessorTestCase.php
@@ -48,11 +48,11 @@ protected function getBinaryInterfaceMock(): BinaryInterface
     protected function assertTemporaryFile(string $content, string $file, string $context, array $options = []): void
     {
         $this->assertFileExists($file);
-        $this->assertContains($context, $file);
+        $this->assertStringContainsString($context, $file);
         $this->assertSame($content, file_get_contents($file));
 
         if (isset($options['temp_dir'])) {
-            $this->assertContains($options['temp_dir'], $file);
+            $this->assertStringContainsString($options['temp_dir'], $file);
         }
     }
 
diff --git a/Tests/Imagine/Filter/PostProcessor/JpegOptimPostProcessorTest.php b/Tests/Imagine/Filter/PostProcessor/JpegOptimPostProcessorTest.php
index c13d5ec6c..1caf9e696 100644
--- a/Tests/Imagine/Filter/PostProcessor/JpegOptimPostProcessorTest.php
+++ b/Tests/Imagine/Filter/PostProcessor/JpegOptimPostProcessorTest.php
@@ -149,8 +149,8 @@ public function testProcess(string $content, array $options, string $expected):
         $process = $this->getPostProcessorInstance();
         $result = $process->process(new FileBinary($file, 'image/jpeg', 'jpeg'), $options);
 
-        $this->assertContains($expected, $result->getContent());
-        $this->assertContains($content, $result->getContent());
+        $this->assertStringContainsString($expected, $result->getContent());
+        $this->assertStringContainsString($content, $result->getContent());
 
         @unlink($file);
     }
diff --git a/Tests/Imagine/Filter/PostProcessor/MozJpegPostProcessorTest.php b/Tests/Imagine/Filter/PostProcessor/MozJpegPostProcessorTest.php
index 9bb74bc35..3393cc44d 100644
--- a/Tests/Imagine/Filter/PostProcessor/MozJpegPostProcessorTest.php
+++ b/Tests/Imagine/Filter/PostProcessor/MozJpegPostProcessorTest.php
@@ -88,8 +88,8 @@ public function testProcess(string $content, array $options, string $expected):
         $process = $this->getPostProcessorInstance();
         $result = $process->process(new FileBinary($file, 'image/jpeg', 'jpeg'), $options);
 
-        $this->assertContains($expected, $result->getContent());
-        $this->assertContains($content, $result->getContent());
+        $this->assertStringContainsString($expected, $result->getContent());
+        $this->assertStringContainsString($content, $result->getContent());
 
         @unlink($file);
     }
@@ -119,6 +119,6 @@ public function testProcessWithNonSupportedMimeType(): void
 
     protected function getPostProcessorInstance(array $parameters = []): MozJpegPostProcessor
     {
-        return new MozJpegPostProcessor($parameters[0] ?? static::getPostProcessAsStdinExecutable());
+        return new MozJpegPostProcessor($parameters[0] ?? static::getPostProcessAsStdInExecutable());
     }
 }
diff --git a/Tests/Imagine/Filter/PostProcessor/OptiPngPostProcessorTest.php b/Tests/Imagine/Filter/PostProcessor/OptiPngPostProcessorTest.php
index 45aa2ecf0..d1cc817a3 100644
--- a/Tests/Imagine/Filter/PostProcessor/OptiPngPostProcessorTest.php
+++ b/Tests/Imagine/Filter/PostProcessor/OptiPngPostProcessorTest.php
@@ -131,7 +131,7 @@ public static function provideProcessData(): array
     /**
      * @dataProvider provideProcessData
      */
-    public function testProcess(string $content, array $options, string $expected)
+    public function testProcess(string $content, array $options, string $expected): void
     {
         $file = sys_get_temp_dir().'/test.png';
         file_put_contents($file, $content);
@@ -139,8 +139,8 @@ public function testProcess(string $content, array $options, string $expected)
         $process = $this->getPostProcessorInstance();
         $result = $process->process(new FileBinary($file, 'image/png', 'png'), $options);
 
-        $this->assertContains($expected, $result->getContent());
-        $this->assertContains($content, $result->getContent());
+        $this->assertStringContainsString($expected, $result->getContent());
+        $this->assertStringContainsString($content, $result->getContent());
 
         @unlink($file);
     }
diff --git a/Tests/LiipImagineBundleTest.php b/Tests/LiipImagineBundleTest.php
index 49cabb3e5..25a84559e 100644
--- a/Tests/LiipImagineBundleTest.php
+++ b/Tests/LiipImagineBundleTest.php
@@ -24,6 +24,7 @@
 use Liip\ImagineBundle\DependencyInjection\Factory\Resolver\WebPathResolverFactory;
 use Liip\ImagineBundle\DependencyInjection\LiipImagineExtension;
 use Liip\ImagineBundle\LiipImagineBundle;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
@@ -32,12 +33,12 @@
  */
 class LiipImagineBundleTest extends AbstractTest
 {
-    public function testSubClassOfBundle()
+    public function testSubClassOfBundle(): void
     {
         $this->assertInstanceOf(Bundle::class, new LiipImagineBundle());
     }
 
-    public function testAddLoadersCompilerPassOnBuild()
+    public function testAddLoadersCompilerPassOnBuild(): void
     {
         $containerMock = $this->createContainerBuilderMock();
         $containerMock
@@ -54,7 +55,7 @@ public function testAddLoadersCompilerPassOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddFiltersCompilerPassOnBuild()
+    public function testAddFiltersCompilerPassOnBuild(): void
     {
         $containerMock = $this->createContainerBuilderMock();
         $containerMock
@@ -71,7 +72,7 @@ public function testAddFiltersCompilerPassOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddPostProcessorsCompilerPassOnBuild()
+    public function testAddPostProcessorsCompilerPassOnBuild(): void
     {
         $containerMock = $this->createContainerBuilderMock();
         $containerMock
@@ -88,7 +89,7 @@ public function testAddPostProcessorsCompilerPassOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddResolversCompilerPassOnBuild()
+    public function testAddResolversCompilerPassOnBuild(): void
     {
         $containerMock = $this->createContainerBuilderMock();
         $containerMock
@@ -105,7 +106,7 @@ public function testAddResolversCompilerPassOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddWebPathResolverFactoryOnBuild()
+    public function testAddWebPathResolverFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -124,7 +125,7 @@ public function testAddWebPathResolverFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddAwsS3ResolverFactoryOnBuild()
+    public function testAddAwsS3ResolverFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -143,7 +144,7 @@ public function testAddAwsS3ResolverFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddFlysystemResolverFactoryOnBuild()
+    public function testAddFlysystemResolverFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -162,7 +163,7 @@ public function testAddFlysystemResolverFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddChainLoaderFactoryOnBuild()
+    public function testAddChainLoaderFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -179,7 +180,7 @@ public function testAddChainLoaderFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddStreamLoaderFactoryOnBuild()
+    public function testAddStreamLoaderFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -198,7 +199,7 @@ public function testAddStreamLoaderFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddFilesystemLoaderFactoryOnBuild()
+    public function testAddFilesystemLoaderFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -217,7 +218,7 @@ public function testAddFilesystemLoaderFactoryOnBuild()
         $bundle->build($containerMock);
     }
 
-    public function testAddFlysystemLoaderFactoryOnBuild()
+    public function testAddFlysystemLoaderFactoryOnBuild(): void
     {
         $extensionMock = $this->createLiipImagineExtensionMock();
         $extensionMock
@@ -237,7 +238,7 @@ public function testAddFlysystemLoaderFactoryOnBuild()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|ContainerBuilder
+     * @return MockObject|ContainerBuilder
      */
     protected function createContainerBuilderMock()
     {
@@ -245,7 +246,7 @@ protected function createContainerBuilderMock()
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject|LiipImagineExtension
+     * @return MockObject|LiipImagineExtension
      */
     protected function createLiipImagineExtensionMock()
     {
diff --git a/Tests/Model/BinaryTest.php b/Tests/Model/BinaryTest.php
index 69d643a82..7bb7526a6 100644
--- a/Tests/Model/BinaryTest.php
+++ b/Tests/Model/BinaryTest.php
@@ -11,6 +11,7 @@
 
 namespace Liip\ImagineBundle\Tests\Model;
 
+use Liip\ImagineBundle\Binary\BinaryInterface;
 use Liip\ImagineBundle\Model\Binary;
 use PHPUnit\Framework\TestCase;
 
@@ -19,28 +20,28 @@
  */
 class BinaryTest extends TestCase
 {
-    public function testImplementsBinaryInterface()
+    public function testImplementsBinaryInterface(): void
     {
         $rc = new \ReflectionClass(Binary::class);
 
-        $this->assertTrue($rc->implementsInterface('\Liip\ImagineBundle\Binary\BinaryInterface'));
+        $this->assertTrue($rc->implementsInterface(BinaryInterface::class));
     }
 
-    public function testAllowGetContentSetInConstructor()
+    public function testAllowGetContentSetInConstructor(): void
     {
         $image = new Binary('theContent', 'image/png', 'png');
 
         $this->assertSame('theContent', $image->getContent());
     }
 
-    public function testAllowGetMimeTypeSetInConstructor()
+    public function testAllowGetMimeTypeSetInConstructor(): void
     {
         $image = new Binary('aContent', 'image/png', 'png');
 
         $this->assertSame('image/png', $image->getMimeType());
     }
 
-    public function testAllowGetFormatSetInConstructor()
+    public function testAllowGetFormatSetInConstructor(): void
     {
         $image = new Binary('aContent', 'image/png', 'png');
 
diff --git a/Tests/Templating/AbstractFilterTest.php b/Tests/Templating/AbstractFilterTest.php
index f27ccf210..634f90f12 100644
--- a/Tests/Templating/AbstractFilterTest.php
+++ b/Tests/Templating/AbstractFilterTest.php
@@ -18,17 +18,17 @@
 
 abstract class AbstractFilterTest extends AbstractTest
 {
-    public function testCanBeConstructed()
+    public function testCanBeConstructed(): void
     {
         $this->createTemplatingMock();
     }
 
-    public function testInvokeGetNameMethod()
+    public function testInvokeGetNameMethod(): void
     {
         $this->assertSame('liip_imagine', $this->createTemplatingMock()->getName());
     }
 
-    public function testInvokeFilterMethod()
+    public function testInvokeFilterMethod(): void
     {
         $expectedFilter = 'thumbnail';
         $expectedInputPath = 'thePathToTheImage';
@@ -45,8 +45,6 @@ public function testInvokeFilterMethod()
     }
 
     /**
-     * @param CacheManager|null $manager
-     *
      * @return FilterExtension|FilterHelper
      */
     abstract protected function createTemplatingMock(CacheManager $manager = null);
diff --git a/Tests/Templating/FilterExtensionTest.php b/Tests/Templating/FilterExtensionTest.php
index 75e940459..aef304e85 100644
--- a/Tests/Templating/FilterExtensionTest.php
+++ b/Tests/Templating/FilterExtensionTest.php
@@ -21,22 +21,17 @@
  */
 class FilterExtensionTest extends AbstractFilterTest
 {
-    public function testAddsFilterMethodToFiltersList()
+    public function testAddsFilterMethodToFiltersList(): void
     {
         $this->assertCount(1, $this->createTemplatingMock()->getFilters());
     }
 
-    public function testInstanceOfTwigFilter()
+    public function testInstanceOfTwigFilter(): void
     {
         $this->assertInstanceOf(AbstractExtension::class, $this->createTemplatingMock());
     }
 
-    /**
-     * @param CacheManager|null $manager
-     *
-     * @return FilterExtension
-     */
-    protected function createTemplatingMock(CacheManager $manager = null)
+    protected function createTemplatingMock(CacheManager $manager = null): FilterExtension
     {
         if (!class_exists(AbstractExtension::class)) {
             $this->markTestSkipped('Requires the twig/twig package.');
diff --git a/Tests/Templating/Helper/FilterHelperTest.php b/Tests/Templating/Helper/FilterHelperTest.php
index 4ceefb0dd..17c6ba664 100644
--- a/Tests/Templating/Helper/FilterHelperTest.php
+++ b/Tests/Templating/Helper/FilterHelperTest.php
@@ -24,17 +24,12 @@
  */
 class FilterHelperTest extends AbstractFilterTest
 {
-    public function testInstanceOfSymfonyHelper()
+    public function testInstanceOfSymfonyHelper(): void
     {
         $this->assertInstanceOf(Helper::class, $this->createTemplatingMock());
     }
 
-    /**
-     * @param CacheManager|null $manager
-     *
-     * @return FilterHelper
-     */
-    protected function createTemplatingMock(CacheManager $manager = null)
+    protected function createTemplatingMock(CacheManager $manager = null): FilterHelper
     {
         $mock = new FilterHelper($manager ?: $this->createCacheManagerMock());
 
diff --git a/Tests/Utility/Framework/SymfonyFrameworkTest.php b/Tests/Utility/Framework/SymfonyFrameworkTest.php
index a9321672a..a48c2837d 100644
--- a/Tests/Utility/Framework/SymfonyFrameworkTest.php
+++ b/Tests/Utility/Framework/SymfonyFrameworkTest.php
@@ -20,7 +20,7 @@
  */
 class SymfonyFrameworkTest extends TestCase
 {
-    public function testKernelComparisonForCurrentKernel()
+    public function testKernelComparisonForCurrentKernel(): void
     {
         $major = Kernel::MAJOR_VERSION;
         $minor = Kernel::MINOR_VERSION;
@@ -29,13 +29,13 @@ public function testKernelComparisonForCurrentKernel()
         $this->assertFalse(SymfonyFramework::isKernelLessThan($major, $minor));
     }
 
-    public function testIsKernelLessThan()
+    public function testIsKernelLessThan(): void
     {
         $this->assertTrue(SymfonyFramework::isKernelLessThan(100, 100, 100));
         $this->assertFalse(SymfonyFramework::isKernelLessThan(1, 1, 1));
     }
 
-    public function testGetContainerResolvableRootWebPath()
+    public function testGetContainerResolvableRootWebPath(): void
     {
         $path = SymfonyFramework::getContainerResolvableRootWebPath();
 
diff --git a/Tests/bootstrap.php b/Tests/bootstrap.php
index 7456f8da3..20bd5f6c7 100644
--- a/Tests/bootstrap.php
+++ b/Tests/bootstrap.php
@@ -23,7 +23,7 @@
 }
 
 namespace Symfony\Component\ExpressionLanguage {
-    if (interface_exists('Symfony\Component\ExpressionLanguage\ExpressionFunctionProviderInterface')) {
+    if (interface_exists(ExpressionFunctionProviderInterface::class)) {
         return;
     }
 
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 3d00787ca..8360fd847 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -2,12 +2,11 @@
 
 <phpunit
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.0/phpunit.xsd"
+        xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/7.5/phpunit.xsd"
         colors="true"
         convertErrorsToExceptions="true"
         convertNoticesToExceptions="true"
         convertWarningsToExceptions="true"
-        syntaxCheck="true"
         forceCoversAnnotation="true"
         bootstrap="./Tests/bootstrap.php">