diff --git a/composer.json b/composer.json
index d110e2a..6f83a32 100644
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
         "evenement/evenement": "^3.0 || ^2.0 || ^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.0 || ^4.8.10",
+        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35",
         "clue/stream-filter": "~1.2"
     },
     "suggest": {
diff --git a/tests/DuplexResourceStreamTest.php b/tests/DuplexResourceStreamTest.php
index 4bc9326..0aba089 100644
--- a/tests/DuplexResourceStreamTest.php
+++ b/tests/DuplexResourceStreamTest.php
@@ -36,17 +36,18 @@ public function testConstructorWithExcessiveMode()
 
     /**
      * @covers React\Stream\DuplexResourceStream::__construct
+     * @expectedException InvalidArgumentException
      */
     public function testConstructorThrowsExceptionOnInvalidStream()
     {
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('InvalidArgumentException');
         new DuplexResourceStream('breakme', $loop);
     }
 
     /**
      * @covers React\Stream\DuplexResourceStream::__construct
+     * @expectedException InvalidArgumentException
      */
     public function testConstructorThrowsExceptionOnWriteOnlyStream()
     {
@@ -56,7 +57,6 @@ public function testConstructorThrowsExceptionOnWriteOnlyStream()
 
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('InvalidArgumentException');
         new DuplexResourceStream(STDOUT, $loop);
     }
 
@@ -77,6 +77,7 @@ public function testConstructorThrowsExceptionOnWriteOnlyStreamWithExcessiveMode
 
     /**
      * @covers React\Stream\DuplexResourceStream::__construct
+     * @expectedException RunTimeException
      */
     public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking()
     {
@@ -87,7 +88,6 @@ public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking(
         $stream = fopen('blocking://test', 'r+');
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('RuntimeException');
         new DuplexResourceStream($stream, $loop);
     }
 
diff --git a/tests/ReadableResourceStreamTest.php b/tests/ReadableResourceStreamTest.php
index 64aa101..8a960e1 100644
--- a/tests/ReadableResourceStreamTest.php
+++ b/tests/ReadableResourceStreamTest.php
@@ -35,17 +35,18 @@ public function testConstructorWithExcessiveMode()
 
     /**
      * @covers React\Stream\ReadableResourceStream::__construct
+     * @expectedException InvalidArgumentException
      */
     public function testConstructorThrowsExceptionOnInvalidStream()
     {
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('InvalidArgumentException');
         new ReadableResourceStream(false, $loop);
     }
 
     /**
      * @covers React\Stream\ReadableResourceStream::__construct
+     * @expectedException InvalidArgumentException
      */
     public function testConstructorThrowsExceptionOnWriteOnlyStream()
     {
@@ -55,7 +56,6 @@ public function testConstructorThrowsExceptionOnWriteOnlyStream()
 
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('InvalidArgumentException');
         new ReadableResourceStream(STDOUT, $loop);
     }
 
@@ -76,6 +76,7 @@ public function testConstructorThrowsExceptionOnWriteOnlyStreamWithExcessiveMode
 
     /**
      * @covers React\Stream\ReadableResourceStream::__construct
+     * @expectedException RuntimeException
      */
     public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking()
     {
@@ -86,7 +87,6 @@ public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking(
         $stream = fopen('blocking://test', 'r+');
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('RuntimeException');
         new ReadableResourceStream($stream, $loop);
     }
 
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 63746f9..c8fc1db 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -2,7 +2,9 @@
 
 namespace React\Tests\Stream;
 
-class TestCase extends \PHPUnit_Framework_TestCase
+use PHPUnit\Framework\TestCase as BaseTestCase;
+
+class TestCase extends BaseTestCase
 {
     protected function expectCallableExactly($amount)
     {
diff --git a/tests/WritableStreamResourceTest.php b/tests/WritableStreamResourceTest.php
index 23da14b..fdf69c3 100644
--- a/tests/WritableStreamResourceTest.php
+++ b/tests/WritableStreamResourceTest.php
@@ -75,6 +75,7 @@ public function testConstructorThrowsExceptionOnReadOnlyStreamWithExcessiveMode(
 
     /**
      * @covers React\Stream\WritableResourceStream::__construct
+     * @expectedException RuntimeException
      */
     public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking()
     {
@@ -85,7 +86,6 @@ public function testConstructorThrowsExceptionIfStreamDoesNotSupportNonBlocking(
         $stream = fopen('blocking://test', 'r+');
         $loop = $this->createLoopMock();
 
-        $this->setExpectedException('RuntimeException');
         new WritableResourceStream($stream, $loop);
     }