diff --git a/composer.json b/composer.json
index 0ca928e..0bf11d2 100644
--- a/composer.json
+++ b/composer.json
@@ -21,11 +21,11 @@
         "php": ">=7.1",
         "clue/socket-raw": "^1.2",
         "psr/log": "^1.0",
-        "symfony/process": "^3.3|^4.0|^5.0"
+        "symfony/process": "^3.3|^4.0|^5.0|^6.0"
     },
     "require-dev": {
         "monolog/monolog": "^1.23",
-        "phpunit/phpunit": "^6.5|^7.0"
+        "phpunit/phpunit": "^6.5|^7.0|^8.0"
     },
     "suggest": {
         "ext-weakref": "Required to run all the tests"
diff --git a/tests/ImplementationTest.php b/tests/ImplementationTest.php
index e16726f..7d653e5 100644
--- a/tests/ImplementationTest.php
+++ b/tests/ImplementationTest.php
@@ -42,7 +42,7 @@ public function can_get_property()
     {
         $constants = $this->fs->constants;
 
-        $this->assertInternalType('array', $constants);
+        $this->assertIsArray($constants);
     }
 
     /** @test */
@@ -258,33 +258,30 @@ public function can_receive_heavy_payloads_with_non_ascii_chars()
         $this->assertStringEndsWith('😘', $payload);
     }
 
-    /**
-     * @test
-     * @expectedException \Nesk\Rialto\Exceptions\Node\FatalException
-     * @expectedExceptionMessage Object.__inexistantMethod__ is not a function
-     */
+    /** @test */
     public function node_crash_throws_a_fatal_exception()
     {
+        $this->expectException(Node\FatalException::class);
+        $this->expectExceptionMessage('Object.__inexistantMethod__ is not a function');
+
         $this->fs->__inexistantMethod__();
     }
 
-    /**
-     * @test
-     * @expectedException \Nesk\Rialto\Exceptions\Node\Exception
-     * @expectedExceptionMessage Object.__inexistantMethod__ is not a function
-     */
+    /** @test */
     public function can_catch_errors()
     {
+        $this->expectException(Node\Exception::class);
+        $this->expectExceptionMessage('Object.__inexistantMethod__ is not a function');
+
         $this->fs->tryCatch->__inexistantMethod__();
     }
 
-    /**
-     * @test
-     * @expectedException \Nesk\Rialto\Exceptions\Node\FatalException
-     * @expectedExceptionMessage Object.__inexistantMethod__ is not a function
-     */
+    /** @test */
     public function catching_a_node_exception_doesnt_catch_fatal_exceptions()
     {
+        $this->expectException(Node\FatalException::class);
+        $this->expectExceptionMessage('Object.__inexistantMethod__ is not a function');
+
         try {
             $this->fs->__inexistantMethod__();
         } catch (Node\Exception $exception) {
@@ -323,13 +320,12 @@ public function node_current_working_directory_is_the_same_as_php()
         $this->assertNull($result);
     }
 
-    /**
-     * @test
-     * @expectedException \Symfony\Component\Process\Exception\ProcessFailedException
-     * @expectedExceptionMessageRegExp /Error Output:\n=+\n.*__inexistant_process__.*not found/
-     */
+    /** @test */
     public function executable_path_option_changes_the_process_prefix()
     {
+        $this->expectException(\Symfony\Component\Process\Exception\ProcessFailedException::class);
+        $this->expectExceptionMessageMatches('/Error Output:\n=+\n.*__inexistant_process__.*not found/');
+
         new FsWithProcessDelegation(['executable_path' => '__inexistant_process__']);
     }
 
@@ -346,7 +342,7 @@ public function idle_timeout_option_closes_node_once_timer_is_reached()
         sleep(1);
 
         $this->expectException(\Nesk\Rialto\Exceptions\IdleTimeoutException::class);
-        $this->expectExceptionMessageRegExp('/^The idle timeout \(0\.500 seconds\) has been exceeded/');
+        $this->expectExceptionMessageMatches('/^The idle timeout \(0\.500 seconds\) has been exceeded/');
 
         $this->fs->constants;
     }
@@ -354,11 +350,12 @@ public function idle_timeout_option_closes_node_once_timer_is_reached()
     /**
      * @test
      * @dontPopulateProperties fs
-     * @expectedException \Nesk\Rialto\Exceptions\ReadSocketTimeoutException
-     * @expectedExceptionMessageRegExp /^The timeout \(0\.010 seconds\) has been exceeded/
      */
     public function read_timeout_option_throws_an_exception_on_long_actions()
     {
+        $this->expectException(\Nesk\Rialto\Exceptions\ReadSocketTimeoutException::class);
+        $this->expectExceptionMessageMatches('/^The timeout \(0\.010 seconds\) has been exceeded/');
+
         $this->fs = new FsWithProcessDelegation(['read_timeout' => 0.01]);
 
         $this->fs->wait(20);
@@ -447,13 +444,7 @@ public function process_status_is_tracked()
     /** @test */
     public function process_is_properly_shutdown_when_there_are_no_more_references()
     {
-        if (!class_exists('WeakRef')) {
-            $this->markTestSkipped(
-                'This test requires weak references (unavailable for PHP 7.3): http://php.net/weakref/'
-            );
-        }
-
-        $ref = new \WeakRef($this->fs->getProcessSupervisor());
+        $ref = \WeakReference::create($this->fs->getProcessSupervisor());
 
         $resource = $this->fs->readFileSync($this->filePath);
 
@@ -462,7 +453,7 @@ public function process_is_properly_shutdown_when_there_are_no_more_references()
         $this->fs = null;
         unset($resource);
 
-        $this->assertFalse($ref->valid());
+        $this->assertNull($ref->get());
     }
 
     /**