diff --git a/Document/AuthCodeManager.php b/Document/AuthCodeManager.php
index bdcc2ad1..b6eff4d7 100644
--- a/Document/AuthCodeManager.php
+++ b/Document/AuthCodeManager.php
@@ -14,7 +14,7 @@
 namespace FOS\OAuthServerBundle\Document;
 
 use Doctrine\ODM\MongoDB\DocumentManager;
-use Doctrine\ODM\MongoDB\DocumentRepository;
+use Doctrine\ODM\MongoDB\Repository\DocumentRepository;
 use FOS\OAuthServerBundle\Model\AuthCodeInterface;
 use FOS\OAuthServerBundle\Model\AuthCodeManager as BaseAuthCodeManager;
 
@@ -46,6 +46,11 @@ public function __construct(DocumentManager $dm, $class)
         $this->class = $class;
     }
 
+    public function getDocumentManager(): DocumentManager
+    {
+        return $this->dm;
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/Document/ClientManager.php b/Document/ClientManager.php
index 73a95d63..ad4e9d1c 100644
--- a/Document/ClientManager.php
+++ b/Document/ClientManager.php
@@ -14,7 +14,7 @@
 namespace FOS\OAuthServerBundle\Document;
 
 use Doctrine\ODM\MongoDB\DocumentManager;
-use Doctrine\ODM\MongoDB\DocumentRepository;
+use Doctrine\ODM\MongoDB\Repository\DocumentRepository;
 use FOS\OAuthServerBundle\Model\ClientInterface;
 use FOS\OAuthServerBundle\Model\ClientManager as BaseClientManager;
 
@@ -46,6 +46,16 @@ public function __construct(DocumentManager $dm, $class)
         $this->class = $class;
     }
 
+    public function getRepository(): DocumentRepository
+    {
+        return $this->repository;
+    }
+
+    public function getDocumentManager(): DocumentManager
+    {
+        return $this->dm;
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/Entity/AuthCodeManager.php b/Entity/AuthCodeManager.php
index 048a9cee..04b51c7d 100644
--- a/Entity/AuthCodeManager.php
+++ b/Entity/AuthCodeManager.php
@@ -39,6 +39,11 @@ public function __construct(EntityManagerInterface $em, $class)
         $this->class = $class;
     }
 
+    public function getEntityManager(): EntityManagerInterface
+    {
+        return $this->em;
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/Entity/ClientManager.php b/Entity/ClientManager.php
index 346c9732..ed80a9e3 100644
--- a/Entity/ClientManager.php
+++ b/Entity/ClientManager.php
@@ -79,4 +79,14 @@ public function deleteClient(ClientInterface $client)
         $this->em->remove($client);
         $this->em->flush();
     }
+
+    public function getEntityManager(): EntityManagerInterface
+    {
+        return $this->em;
+    }
+
+    public function getRepository(): EntityRepository
+    {
+        return $this->repository;
+    }
 }
diff --git a/Entity/TokenManager.php b/Entity/TokenManager.php
index 4a87c17f..4843618a 100644
--- a/Entity/TokenManager.php
+++ b/Entity/TokenManager.php
@@ -94,4 +94,14 @@ public function deleteExpired()
 
         return $qb->getQuery()->execute();
     }
+
+    public function getEntityManager(): EntityManagerInterface
+    {
+        return $this->em;
+    }
+
+    public function getRepository(): EntityRepository
+    {
+        return $this->repository;
+    }
 }
diff --git a/Form/Handler/AuthorizeFormHandler.php b/Form/Handler/AuthorizeFormHandler.php
index b0681345..f8adbae4 100644
--- a/Form/Handler/AuthorizeFormHandler.php
+++ b/Form/Handler/AuthorizeFormHandler.php
@@ -137,4 +137,14 @@ private function getCurrentRequest()
 
         return $this->requestStack->getCurrentRequest();
     }
+
+    public function getForm(): FormInterface
+    {
+        return $this->form;
+    }
+
+    public function getRequest()
+    {
+        return $this->requestStack;
+    }
 }
diff --git a/Tests/Command/CreateClientCommandTest.php b/Tests/Command/CreateClientCommandTest.php
index 6230dad8..9ca70b78 100644
--- a/Tests/Command/CreateClientCommandTest.php
+++ b/Tests/Command/CreateClientCommandTest.php
@@ -80,7 +80,7 @@ public function testItShouldCreateClient($client): void
             ],
         ]);
 
-        $this->assertSame(0, $commandTester->getStatusCode());
+        self::assertSame(0, $commandTester->getStatusCode());
 
         $output = $commandTester->getDisplay();
 
diff --git a/Tests/Controller/AuthorizeControllerTest.php b/Tests/Controller/AuthorizeControllerTest.php
index 6d4d24ab..393593df 100644
--- a/Tests/Controller/AuthorizeControllerTest.php
+++ b/Tests/Controller/AuthorizeControllerTest.php
@@ -325,7 +325,7 @@ public function testAuthorizeActionWillRenderTemplate(): void
             ->willReturn($response)
         ;
 
-        $this->assertSame($response, $this->instance->authorizeAction($this->request));
+        self::assertSame($response, $this->instance->authorizeAction($this->request));
     }
 
     public function testAuthorizeActionWillFinishClientAuthorization(): void
@@ -395,7 +395,7 @@ public function testAuthorizeActionWillFinishClientAuthorization(): void
             ->willReturn($response)
         ;
 
-        $this->assertSame($response, $this->instance->authorizeAction($this->request));
+        self::assertSame($response, $this->instance->authorizeAction($this->request));
     }
 
     public function testAuthorizeActionWillEnsureLogout(): void
@@ -484,7 +484,7 @@ public function testAuthorizeActionWillEnsureLogout(): void
             ->willReturn($response)
         ;
 
-        $this->assertSame($response, $this->instance->authorizeAction($this->request));
+        self::assertSame($response, $this->instance->authorizeAction($this->request));
     }
 
     public function testAuthorizeActionWillProcessAuthorizationForm(): void
@@ -594,6 +594,6 @@ public function testAuthorizeActionWillProcessAuthorizationForm(): void
             ->willReturn($response)
         ;
 
-        $this->assertSame($response, $this->instance->authorizeAction($this->request));
+        self::assertSame($response, $this->instance->authorizeAction($this->request));
     }
 }
diff --git a/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php b/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
index 9875cd8a..b819f7c8 100644
--- a/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
+++ b/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
@@ -100,8 +100,8 @@ public function testLoadAuthorizeRouting()
 
         $collection = $loader->load(__DIR__.'/../../Resources/config/routing/authorize.xml');
         $authorizeRoute = $collection->get('fos_oauth_server_authorize');
-        $this->assertSame('/oauth/v2/auth', $authorizeRoute->getPath());
-        $this->assertSame(['GET', 'POST'], $authorizeRoute->getMethods());
+        self::assertSame('/oauth/v2/auth', $authorizeRoute->getPath());
+        self::assertSame(['GET', 'POST'], $authorizeRoute->getMethods());
     }
 
     public function testLoadTokenRouting()
@@ -111,8 +111,8 @@ public function testLoadTokenRouting()
 
         $collection = $loader->load(__DIR__.'/../../Resources/config/routing/token.xml');
         $tokenRoute = $collection->get('fos_oauth_server_token');
-        $this->assertSame('/oauth/v2/token', $tokenRoute->getPath());
-        $this->assertSame(['GET', 'POST'], $tokenRoute->getMethods());
+        self::assertSame('/oauth/v2/token', $tokenRoute->getPath());
+        self::assertSame(['GET', 'POST'], $tokenRoute->getMethods());
     }
 
     public function testWithoutService()
@@ -127,7 +127,7 @@ public function testWithoutService()
         $instance = new FOSOAuthServerExtension();
         $instance->load([$config], $this->container);
 
-        $this->assertSame(
+        self::assertSame(
             $this->container->getParameter('fos_oauth_server.server.options'),
             []
         );
@@ -153,7 +153,7 @@ public function testStringSupportedScopes()
         $instance = new FOSOAuthServerExtension();
         $instance->load([$config], $this->container);
 
-        $this->assertSame(
+        self::assertSame(
             $this->container->getParameter('fos_oauth_server.server.options'),
             [
                 'supported_scopes' => 'scope1 scope2 scope3 scope4',
@@ -181,7 +181,7 @@ public function testArraySupportedScopes()
         $instance = new FOSOAuthServerExtension();
         $instance->load([$config], $this->container);
 
-        $this->assertSame(
+        self::assertSame(
             $this->container->getParameter('fos_oauth_server.server.options'),
             [
                 'supported_scopes' => 'scope1 scope2 scope3 scope4',
@@ -235,18 +235,18 @@ public function testShouldAliasServivesWhenCustomDriverIsUsed()
         ]], $container);
 
         $this->assertTrue($container->hasAlias('fos_oauth_server.storage'));
-        $this->assertSame('fos_oauth_server.storage.default', (string) $container->getAlias('fos_oauth_server.storage'));
+        self::assertSame('fos_oauth_server.storage.default', (string) $container->getAlias('fos_oauth_server.storage'));
 
         $this->assertTrue($container->hasAlias('fos_oauth_server.client_manager'));
-        $this->assertSame('the_client_manager_id', (string) $container->getAlias('fos_oauth_server.client_manager'));
+        self::assertSame('the_client_manager_id', (string) $container->getAlias('fos_oauth_server.client_manager'));
 
         $this->assertTrue($container->hasAlias('fos_oauth_server.access_token_manager'));
-        $this->assertSame('the_access_token_manager_id', (string) $container->getAlias('fos_oauth_server.access_token_manager'));
+        self::assertSame('the_access_token_manager_id', (string) $container->getAlias('fos_oauth_server.access_token_manager'));
 
         $this->assertTrue($container->hasAlias('fos_oauth_server.refresh_token_manager'));
-        $this->assertSame('the_refresh_token_manager_id', (string) $container->getAlias('fos_oauth_server.refresh_token_manager'));
+        self::assertSame('the_refresh_token_manager_id', (string) $container->getAlias('fos_oauth_server.refresh_token_manager'));
 
         $this->assertTrue($container->hasAlias('fos_oauth_server.auth_code_manager'));
-        $this->assertSame('the_auth_code_manager_id', (string) $container->getAlias('fos_oauth_server.auth_code_manager'));
+        self::assertSame('the_auth_code_manager_id', (string) $container->getAlias('fos_oauth_server.auth_code_manager'));
     }
 }
diff --git a/Tests/DependencyInjection/Security/Factory/OAuthFactoryTest.php b/Tests/DependencyInjection/Security/Factory/OAuthFactoryTest.php
index f538d59c..47a13f0c 100644
--- a/Tests/DependencyInjection/Security/Factory/OAuthFactoryTest.php
+++ b/Tests/DependencyInjection/Security/Factory/OAuthFactoryTest.php
@@ -55,12 +55,12 @@ public function setUp() : void
 
     public function testGetPosition()
     {
-        $this->assertSame('pre_auth', $this->instance->getPosition());
+        self::assertSame('pre_auth', $this->instance->getPosition());
     }
 
     public function testGetKey()
     {
-        $this->assertSame('fos_oauth', $this->instance->getKey());
+        self::assertSame('fos_oauth', $this->instance->getKey());
     }
 
     public function testCreate()
@@ -130,7 +130,7 @@ protected function useDefinitionDecorator()
             ->willReturn(null)
         ;
 
-        $this->assertSame([
+        self::assertSame([
             'security.authentication.provider.fos_oauth_server.'.$id,
             'security.authentication.listener.fos_oauth_server.'.$id,
             'fos_oauth_server.security.entry_point',
@@ -182,7 +182,7 @@ protected function useChildDefinition()
             ->willReturn(null)
         ;
 
-        $this->assertSame([
+        self::assertSame([
             'security.authentication.provider.fos_oauth_server.'.$id,
             'security.authentication.listener.fos_oauth_server.'.$id,
             'fos_oauth_server.security.entry_point',
diff --git a/Tests/Document/AuthCodeManagerTest.php b/Tests/Document/AuthCodeManagerTest.php
index 61293731..ffb12db8 100644
--- a/Tests/Document/AuthCodeManagerTest.php
+++ b/Tests/Document/AuthCodeManagerTest.php
@@ -81,13 +81,13 @@ public function setUp() : void
 
     public function testConstructWillSetParameters(): void
     {
-        $this->assertAttributeSame($this->documentManager, 'dm', $this->instance);
-        $this->assertAttributeSame($this->className, 'class', $this->instance);
+        self::assertSame($this->documentManager, $this->instance->getDocumentManager());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
     public function testGetClassWillReturnClassName(): void
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
     public function testFindAuthCodeBy(): void
@@ -104,7 +104,7 @@ public function testFindAuthCodeBy(): void
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findAuthCodeBy($criteria));
+        self::assertSame($randomResult, $this->instance->findAuthCodeBy($criteria));
     }
 
     public function testUpdateAuthCode(): void
@@ -218,6 +218,6 @@ public function testDeleteExpired(): void
             ->willReturn($data)
         ;
 
-        $this->assertSame($data['n'], $this->instance->deleteExpired());
+        self::assertSame($data['n'], $this->instance->deleteExpired());
     }
 }
diff --git a/Tests/Document/ClientManagerTest.php b/Tests/Document/ClientManagerTest.php
index 611e3eb8..11ef3373 100644
--- a/Tests/Document/ClientManagerTest.php
+++ b/Tests/Document/ClientManagerTest.php
@@ -17,6 +17,7 @@
 use Doctrine\ODM\MongoDB\Repository\DocumentRepository;
 use FOS\OAuthServerBundle\Document\ClientManager;
 use FOS\OAuthServerBundle\Model\ClientInterface;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * Class ClientManagerTest.
@@ -26,7 +27,7 @@
 class ClientManagerTest extends \PHPUnit\Framework\TestCase
 {
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|DocumentManager
+     * @var MockObject|DocumentManager
      */
     protected $documentManager;
 
@@ -36,7 +37,7 @@ class ClientManagerTest extends \PHPUnit\Framework\TestCase
     protected $className;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|DocumentRepository
+     * @var MockObject|DocumentRepository
      */
     protected $repository;
 
@@ -73,19 +74,19 @@ public function setUp() : void
         parent::setUp();
     }
 
-    public function testConstructWillSetParameters()
+    public function testConstructWillSetParameters(): void
     {
-        $this->assertAttributeSame($this->documentManager, 'dm', $this->instance);
-        $this->assertAttributeSame($this->repository, 'repository', $this->instance);
-        $this->assertAttributeSame($this->className, 'class', $this->instance);
+        self::assertSame($this->documentManager, $this->instance->getDocumentManager());
+        self::assertSame($this->repository, $this->instance->getRepository());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testGetClass()
+    public function testGetClass(): void
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testFindClientBy()
+    public function testFindClientBy(): void
     {
         $randomResult = \random_bytes(5);
         $criteria = [
@@ -99,7 +100,7 @@ public function testFindClientBy()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findClientBy($criteria));
+        self::assertSame($randomResult, $this->instance->findClientBy($criteria));
     }
 
     public function testUpdateClient()
diff --git a/Tests/Document/TokenManagerTest.php b/Tests/Document/TokenManagerTest.php
index 8b65da18..2b52c0aa 100644
--- a/Tests/Document/TokenManagerTest.php
+++ b/Tests/Document/TokenManagerTest.php
@@ -90,7 +90,7 @@ public function testFindTokenByToken()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findTokenByToken($randomToken));
+        self::assertSame($randomResult, $this->instance->findTokenByToken($randomToken));
     }
 
     public function testUpdateTokenPersistsAndFlushes()
@@ -117,7 +117,7 @@ public function testUpdateTokenPersistsAndFlushes()
 
     public function testGetClass()
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
     public function testDeleteToken()
@@ -204,6 +204,6 @@ public function testDeleteExpired()
             ->willReturn($data)
         ;
 
-        $this->assertSame($data['n'], $this->instance->deleteExpired());
+        self::assertSame($data['n'], $this->instance->deleteExpired());
     }
 }
diff --git a/Tests/Entity/AuthCodeManagerTest.php b/Tests/Entity/AuthCodeManagerTest.php
index fec01586..58c2747e 100644
--- a/Tests/Entity/AuthCodeManagerTest.php
+++ b/Tests/Entity/AuthCodeManagerTest.php
@@ -20,6 +20,7 @@
 use Doctrine\ORM\QueryBuilder;
 use FOS\OAuthServerBundle\Entity\AuthCodeManager;
 use FOS\OAuthServerBundle\Model\AuthCodeInterface;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -32,7 +33,7 @@
 class AuthCodeManagerTest extends TestCase
 {
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|EntityManagerInterface
+     * @var MockObject|EntityManagerInterface
      */
     protected $entityManager;
 
@@ -59,18 +60,18 @@ public function setUp() : void
         parent::setUp();
     }
 
-    public function testConstructWillSetParameters()
+    public function testConstructWillSetParameters(): void
     {
-        $this->assertAttributeSame($this->entityManager, 'em', $this->instance);
-        $this->assertAttributeSame($this->className, 'class', $this->instance);
+        self::assertSame($this->entityManager, $this->instance->getEntityManager());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testGetClassWillReturnClassName()
+    public function testGetClassWillReturnClassName(): void
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testFindAuthCodeBy()
+    public function testFindAuthCodeBy(): void
     {
         $repository = $this->getMockBuilder(ObjectRepository::class)
             ->disableOriginalConstructor()
@@ -96,10 +97,10 @@ public function testFindAuthCodeBy()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findAuthCodeBy($criteria));
+        self::assertSame($randomResult, $this->instance->findAuthCodeBy($criteria));
     }
 
-    public function testUpdateAuthCode()
+    public function testUpdateAuthCode(): void
     {
         $authCode = $this->getMockBuilder(AuthCodeInterface::class)
             ->disableOriginalConstructor()
@@ -123,7 +124,7 @@ public function testUpdateAuthCode()
         $this->assertNull($this->instance->updateAuthCode($authCode));
     }
 
-    public function testDeleteAuthCode()
+    public function testDeleteAuthCode(): void
     {
         $authCode = $this->getMockBuilder(AuthCodeInterface::class)
             ->disableOriginalConstructor()
@@ -147,7 +148,7 @@ public function testDeleteAuthCode()
         $this->assertNull($this->instance->deleteAuthCode($authCode));
     }
 
-    public function testDeleteExpired()
+    public function testDeleteExpired(): void
     {
         $randomResult = \random_bytes(10);
 
@@ -215,6 +216,6 @@ public function testDeleteExpired()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->deleteExpired());
+        self::assertSame($randomResult, $this->instance->deleteExpired());
     }
 }
diff --git a/Tests/Entity/ClientManagerTest.php b/Tests/Entity/ClientManagerTest.php
index 8cab127b..7a7d6f84 100644
--- a/Tests/Entity/ClientManagerTest.php
+++ b/Tests/Entity/ClientManagerTest.php
@@ -17,6 +17,7 @@
 use Doctrine\ORM\EntityRepository;
 use FOS\OAuthServerBundle\Entity\ClientManager;
 use FOS\OAuthServerBundle\Model\ClientInterface;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -27,7 +28,7 @@
 class ClientManagerTest extends TestCase
 {
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|EntityManagerInterface
+     * @var MockObject|EntityManagerInterface
      */
     protected $entityManager;
 
@@ -37,7 +38,7 @@ class ClientManagerTest extends TestCase
     protected $className;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject|EntityRepository
+     * @var MockObject|EntityRepository
      */
     protected $repository;
 
@@ -70,19 +71,19 @@ public function setUp() : void
         parent::setUp();
     }
 
-    public function testConstructWillSetParameters()
+    public function testConstructWillSetParameters(): void
     {
-        $this->assertAttributeSame($this->entityManager, 'em', $this->instance);
-        $this->assertAttributeSame($this->repository, 'repository', $this->instance);
-        $this->assertAttributeSame($this->className, 'class', $this->instance);
+        self::assertSame($this->entityManager, $this->instance->getEntityManager());
+        self::assertSame($this->repository, $this->instance->getRepository());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testGetClass()
+    public function testGetClass(): void
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testFindClientBy()
+    public function testFindClientBy(): void
     {
         $criteria = [
             \random_bytes(5),
@@ -96,10 +97,10 @@ public function testFindClientBy()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findClientBy($criteria));
+        self::assertSame($randomResult, $this->instance->findClientBy($criteria));
     }
 
-    public function testUpdateClient()
+    public function testUpdateClient(): void
     {
         $client = $this->getMockBuilder(ClientInterface::class)
             ->disableOriginalConstructor()
diff --git a/Tests/Entity/TokenManagerTest.php b/Tests/Entity/TokenManagerTest.php
index 33382019..a5b5765c 100644
--- a/Tests/Entity/TokenManagerTest.php
+++ b/Tests/Entity/TokenManagerTest.php
@@ -74,14 +74,14 @@ public function setUp() : void
         $this->instance = new TokenManager($this->entityManager, $this->className);
     }
 
-    public function testConstructWillSetParameters()
+    public function testConstructWillSetParameters(): void
     {
-        $this->assertAttributeSame($this->entityManager, 'em', $this->instance);
-        $this->assertAttributeSame($this->repository, 'repository', $this->instance);
-        $this->assertAttributeSame($this->className, 'class', $this->instance);
+        self::assertSame($this->entityManager, $this->instance->getEntityManager());
+        self::assertSame($this->repository, $this->instance->getRepository());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
-    public function testUpdateTokenPersistsAndFlushes()
+    public function testUpdateTokenPersistsAndFlushes(): void
     {
         $token = new AccessToken();
 
@@ -102,7 +102,7 @@ public function testUpdateTokenPersistsAndFlushes()
 
     public function testGetClass()
     {
-        $this->assertSame($this->className, $this->instance->getClass());
+        self::assertSame($this->className, $this->instance->getClass());
     }
 
     public function testFindTokenBy()
@@ -120,7 +120,7 @@ public function testFindTokenBy()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->findTokenBy($criteria));
+        self::assertSame($randomResult, $this->instance->findTokenBy($criteria));
     }
 
     public function testUpdateToken()
@@ -227,6 +227,6 @@ public function testDeleteExpired()
             ->willReturn($randomResult)
         ;
 
-        $this->assertSame($randomResult, $this->instance->deleteExpired());
+        self::assertSame($randomResult, $this->instance->deleteExpired());
     }
 }
diff --git a/Tests/Form/Handler/AuthorizeFormHandlerTest.php b/Tests/Form/Handler/AuthorizeFormHandlerTest.php
index 28f65e84..2895980f 100644
--- a/Tests/Form/Handler/AuthorizeFormHandlerTest.php
+++ b/Tests/Form/Handler/AuthorizeFormHandlerTest.php
@@ -15,7 +15,10 @@
 
 use FOS\OAuthServerBundle\Form\Handler\AuthorizeFormHandler;
 use FOS\OAuthServerBundle\Form\Model\Authorize;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
+use ReflectionException;
+use ReflectionMethod;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\Form\FormInterface;
 use Symfony\Component\HttpFoundation\ParameterBag;
@@ -24,6 +27,7 @@
 
 class AuthorizeFormHandlerTest extends TestCase
 {
+    /** @var MockObject | FormInterface */
     protected $form;
 
     protected $request;
@@ -32,6 +36,7 @@ class AuthorizeFormHandlerTest extends TestCase
 
     protected $requestRequest;
 
+    /** @var MockObject | ContainerInterface */
     protected $container;
 
     /**
@@ -82,8 +87,7 @@ public function testConstructWillAcceptRequestObjectAsRequest()
 
         $this->instance = new AuthorizeFormHandler($this->form, $request);
 
-        $this->assertAttributeSame($this->form, 'form', $this->instance);
-        $this->assertAttributeSame($request, 'requestStack', $this->instance);
+        $this->assertAttributesWereSet($request);
     }
 
     public function testConstructWillAcceptRequestStackObjectAsRequest()
@@ -95,19 +99,16 @@ public function testConstructWillAcceptRequestStackObjectAsRequest()
 
         $this->instance = new AuthorizeFormHandler($this->form, $requestStack);
 
-        $this->assertAttributeSame($this->form, 'form', $this->instance);
-        $this->assertAttributeSame($requestStack, 'requestStack', $this->instance);
+        $this->assertAttributesWereSet($requestStack);
     }
 
     public function testConstructWillAcceptNullAsRequest()
     {
         $this->instance = new AuthorizeFormHandler($this->form, null);
-        $this->assertAttributeSame($this->form, 'form', $this->instance);
-        $this->assertAttributeSame(null, 'requestStack', $this->instance);
+        $this->assertAttributesWereSet(null);
 
         $this->instance = new AuthorizeFormHandler($this->form);
-        $this->assertAttributeSame($this->form, 'form', $this->instance);
-        $this->assertAttributeSame(null, 'requestStack', $this->instance);
+        $this->assertAttributesWereSet(null);
     }
 
     public function testConstructWillThrowException()
@@ -135,7 +136,7 @@ public function testIsAcceptedWillProxyValueToFormData()
             ->willReturn($data)
         ;
 
-        $this->assertSame($data->accepted, $this->instance->isAccepted());
+        self::assertSame($data->accepted, $this->instance->isAccepted());
     }
 
     public function testIsRejectedWillNegateAcceptedValueFromFormData()
@@ -171,13 +172,13 @@ public function testGetScopeWillProxyValueToFormData()
             ->willReturn($data)
         ;
 
-        $this->assertSame($data->scope, $this->instance->getScope());
+        self::assertSame($data->scope, $this->instance->getScope());
     }
 
     public function testGetCurrentRequestWillReturnRequestObject()
     {
         $method = $this->getReflectionMethod('getCurrentRequest');
-        $this->assertSame($this->request, $method->invoke($this->instance));
+        self::assertSame($this->request, $method->invoke($this->instance));
     }
 
     public function testGetCurrentRequestWillReturnCurrentRequestFromRequestStack()
@@ -198,7 +199,7 @@ public function testGetCurrentRequestWillReturnCurrentRequestFromRequestStack()
         ;
 
         $method = $this->getReflectionMethod('getCurrentRequest');
-        $this->assertSame($request, $method->invoke($this->instance));
+        self::assertSame($request, $method->invoke($this->instance));
     }
 
     public function testGetCurrentRequestWillReturnRequestServiceFromContainerIfNoneIsSet()
@@ -216,7 +217,7 @@ public function testGetCurrentRequestWillReturnRequestServiceFromContainerIfNone
         ;
 
         $method = $this->getReflectionMethod('getCurrentRequest');
-        $this->assertSame($randomData, $method->invoke($this->instance));
+        self::assertSame($randomData, $method->invoke($this->instance));
     }
 
     /**
@@ -252,7 +253,7 @@ public function testOnSuccessWillReplaceGETSuperGlobal()
 
         $this->assertNull($method->invoke($this->instance));
 
-        $this->assertSame($expectedSuperGlobalValue, $_GET);
+        self::assertSame($expectedSuperGlobalValue, $_GET);
     }
 
     public function testProcessWillReturnFalseIfRequestIsNull()
@@ -436,7 +437,7 @@ public function testProcessWillHandleRequestOnPostAndWillProcessDataIfFormIsVali
             ->willReturn($formData)
         ;
 
-        $this->assertSame([], $_GET);
+        self::assertSame([], $_GET);
 
         $expectedSuperGlobalValue = [
             'client_id' => $query->client_id,
@@ -448,15 +449,16 @@ public function testProcessWillHandleRequestOnPostAndWillProcessDataIfFormIsVali
 
         $this->assertTrue($this->instance->process());
 
-        $this->assertSame($expectedSuperGlobalValue, $_GET);
+        self::assertSame($expectedSuperGlobalValue, $_GET);
     }
 
+
     /**
-     * @param string $methodName
-     *
-     * @return \ReflectionMethod
+     * @param $methodName
+     * @return ReflectionMethod
+     * @throws ReflectionException
      */
-    protected function getReflectionMethod($methodName)
+    protected function getReflectionMethod($methodName): ReflectionMethod
     {
         $reflectionObject = new \ReflectionObject($this->instance);
         $reflectionMethod = $reflectionObject->getMethod($methodName);
@@ -464,4 +466,13 @@ protected function getReflectionMethod($methodName)
 
         return $reflectionMethod;
     }
+
+    /**
+     * @param MockObject $request
+     */
+    private function assertAttributesWereSet(?MockObject $request): void
+    {
+        self::assertSame($this->form, $this->instance->getForm());
+        self::assertSame($request, $this->instance->getRequest());
+    }
 }
diff --git a/Tests/Form/Type/AuthorizeFormTypeTest.php b/Tests/Form/Type/AuthorizeFormTypeTest.php
index 0afa5d6d..0f734ad0 100644
--- a/Tests/Form/Type/AuthorizeFormTypeTest.php
+++ b/Tests/Form/Type/AuthorizeFormTypeTest.php
@@ -16,6 +16,7 @@
 use FOS\OAuthServerBundle\Form\Model\Authorize;
 use FOS\OAuthServerBundle\Form\Type\AuthorizeFormType;
 use FOS\OAuthServerBundle\Util\LegacyFormHelper;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\Form\FormBuilder;
 use Symfony\Component\Form\Forms;
 use Symfony\Component\Form\Test\TypeTestCase;
@@ -42,7 +43,7 @@ protected function setUp() : void
         $this->instance = new AuthorizeFormType();
     }
 
-    public function testSubmit()
+    public function testSubmit(): void
     {
         $accepted = true;
         $formData = [
@@ -55,13 +56,13 @@ public function testSubmit()
 
         $authorize = new Authorize($accepted, $formData);
 
-        $form = $this->factory->create(LegacyFormHelper::getType('FOS\OAuthServerBundle\Form\Type\AuthorizeFormType'), $authorize);
+        $form = $this->factory->create(LegacyFormHelper::getType(AuthorizeFormType::class), $authorize);
 
         $form->submit($formData);
 
         $this->assertTrue($form->isSynchronized());
-        $this->assertSame($authorize, $form->getData());
-        $this->assertSame($accepted, $authorize->accepted);
+        self::assertSame($authorize, $form->getData());
+        self::assertSame($accepted, $authorize->accepted);
 
         $view = $form->createView();
         $children = $view->children;
@@ -71,9 +72,9 @@ public function testSubmit()
         }
     }
 
-    public function testConfigureOptionsWillSetDefaultsOnTheOptionsResolver()
+    public function testConfigureOptionsWillSetDefaultsOnTheOptionsResolver(): void
     {
-        /** @var \PHPUnit_Framework_MockObject_MockObject|OptionsResolver $resolver */
+        /** @var MockObject|OptionsResolver $resolver */
         $resolver = $this->getMockBuilder(OptionsResolver::class)
             ->disableOriginalConstructor()
             ->getMock()
@@ -83,7 +84,7 @@ public function testConfigureOptionsWillSetDefaultsOnTheOptionsResolver()
             ->expects($this->once())
             ->method('setDefaults')
             ->with([
-                'data_class' => 'FOS\OAuthServerBundle\Form\Model\Authorize',
+                'data_class' => Authorize::class,
             ])
             ->willReturn($resolver)
         ;
@@ -91,14 +92,14 @@ public function testConfigureOptionsWillSetDefaultsOnTheOptionsResolver()
         $this->assertNull($this->instance->configureOptions($resolver));
     }
 
-    public function testGetName()
+    public function testGetName(): void
     {
-        $this->assertSame('fos_oauth_server_authorize', $this->instance->getName());
+        self::assertSame('fos_oauth_server_authorize', $this->instance->getName());
     }
 
-    public function testGetBlockPrefix()
+    public function testGetBlockPrefix(): void
     {
-        $this->assertSame('fos_oauth_server_authorize', $this->instance->getBlockPrefix());
+        self::assertSame('fos_oauth_server_authorize', $this->instance->getBlockPrefix());
     }
 
     protected function getTypes()
diff --git a/Tests/Model/TokenTest.php b/Tests/Model/TokenTest.php
index 053032c3..3a072758 100644
--- a/Tests/Model/TokenTest.php
+++ b/Tests/Model/TokenTest.php
@@ -35,7 +35,7 @@ public function testHasExpired($expiresAt, $expect)
         $token = new Token();
         $token->setExpiresAt($expiresAt);
 
-        $this->assertSame($expect, $token->hasExpired());
+        self::assertSame($expect, $token->hasExpired());
     }
 
     public static function getTestHasExpiredData()
@@ -51,7 +51,7 @@ public function testExpiresIn()
     {
         $token = new Token();
 
-        $this->assertSame(PHP_INT_MAX, $token->getExpiresIn());
+        self::assertSame(PHP_INT_MAX, $token->getExpiresIn());
     }
 
     public function testExpiresInWithExpiresAt()
@@ -59,6 +59,6 @@ public function testExpiresInWithExpiresAt()
         $token = new Token();
         $token->setExpiresAt(time() + 60);
 
-        $this->assertSame(60, $token->getExpiresIn());
+        self::assertSame(60, $token->getExpiresIn());
     }
 }
diff --git a/Tests/Propel/AuthCodeManagerTest.php b/Tests/Propel/AuthCodeManagerTest.php
index b571ef2a..87a25c14 100644
--- a/Tests/Propel/AuthCodeManagerTest.php
+++ b/Tests/Propel/AuthCodeManagerTest.php
@@ -38,7 +38,7 @@ public function setUp() : void
 
     public function testConstruct(): void
     {
-        $this->assertSame(self::AUTH_CODE_CLASS, $this->manager->getClass());
+        self::assertSame(self::AUTH_CODE_CLASS, $this->manager->getClass());
     }
 
     public function testCreateClass()
@@ -87,7 +87,7 @@ public function testFindAuthCode()
         $return = $this->manager->findAuthCodeBy(['token' => '12345']);
 
         $this->assertNotNull($return);
-        $this->assertSame($authCode, $return);
+        self::assertSame($authCode, $return);
     }
 
     public function testFindAuthCodeByToken()
@@ -96,7 +96,7 @@ public function testFindAuthCodeByToken()
         $return = $this->manager->findAuthCodeByToken('12345');
 
         $this->assertNotNull($return);
-        $this->assertSame($authCode, $return);
+        self::assertSame($authCode, $return);
     }
 
     public function testFindAuthCodeByTokenReturnsNullIfNotFound()
@@ -123,11 +123,11 @@ public function testDeleteExpired()
         $a1 = $this->createAuthCode('12345', time() + 100);
         $a2 = $this->createAuthCode('67890', time() - 100);
 
-        $this->assertSame(2, AuthCodeQuery::create()->count());
+        self::assertSame(2, AuthCodeQuery::create()->count());
 
         $nb = $this->manager->deleteExpired();
 
-        $this->assertSame(1, $nb);
+        self::assertSame(1, $nb);
         $this->assertTrue($a1->equals(AuthCodeQuery::create()->findOne()));
     }
 
diff --git a/Tests/Propel/AuthCodeTest.php b/Tests/Propel/AuthCodeTest.php
index e8993bc4..6b68952d 100644
--- a/Tests/Propel/AuthCodeTest.php
+++ b/Tests/Propel/AuthCodeTest.php
@@ -33,7 +33,7 @@ public function testHasExpired($expiresAt, $expect)
         $token = new AuthCode();
         $token->setExpiresAt($expiresAt);
 
-        $this->assertSame($expect, $token->hasExpired());
+        self::assertSame($expect, $token->hasExpired());
     }
 
     public static function getTestHasExpiredData()
@@ -49,7 +49,7 @@ public function testExpiresIn()
     {
         $token = new AuthCode();
 
-        $this->assertSame(PHP_INT_MAX, $token->getExpiresIn());
+        self::assertSame(PHP_INT_MAX, $token->getExpiresIn());
     }
 
     public function testExpiresInWithExpiresAt()
@@ -57,6 +57,6 @@ public function testExpiresInWithExpiresAt()
         $token = new AuthCode();
         $token->setExpiresAt(time() + 60);
 
-        $this->assertSame(60, $token->getExpiresIn());
+        self::assertSame(60, $token->getExpiresIn());
     }
 }
diff --git a/Tests/Propel/ClientManagerTest.php b/Tests/Propel/ClientManagerTest.php
index d5cbd655..c6109ebc 100644
--- a/Tests/Propel/ClientManagerTest.php
+++ b/Tests/Propel/ClientManagerTest.php
@@ -33,7 +33,7 @@ public function setUp() : void
 
     public function testConstruct()
     {
-        $this->assertSame(self::CLIENT_CLASS, $this->manager->getClass());
+        self::assertSame(self::CLIENT_CLASS, $this->manager->getClass());
     }
 
     public function testCreateClass()
@@ -43,7 +43,7 @@ public function testCreateClass()
 
     public function testUpdate()
     {
-        $client = $this->getMockBuilder('FOS\OAuthServerBundle\Propel\Client')
+        $client = $this->getMockBuilder(Client::class)
             ->disableOriginalConstructor()
             ->getMock()
         ;
@@ -57,7 +57,8 @@ public function testUpdate()
 
     public function testDelete()
     {
-        $client = $this->getMockBuilder('FOS\OAuthServerBundle\Propel\Client')
+        /** @var Client $client */
+        $client = $this->getMockBuilder(Client::class)
             ->disableOriginalConstructor()
             ->getMock()
         ;
@@ -94,7 +95,7 @@ public function testFindClient()
         $return = $this->manager->findClientBy(['id' => '1', 'randomId' => '2345']);
 
         $this->assertNotNull($return);
-        $this->assertSame($client, $return);
+        self::assertSame($client, $return);
     }
 
     public function testFindClientByPublicId()
@@ -103,7 +104,7 @@ public function testFindClientByPublicId()
         $return = $this->manager->findClientByPublicId('1_12345');
 
         $this->assertNotNull($return);
-        $this->assertSame($client, $return);
+        self::assertSame($client, $return);
     }
 
     public function testFindClientByPublicIdReturnsNullIfNotFound()
diff --git a/Tests/Propel/ClientTest.php b/Tests/Propel/ClientTest.php
index f10cb282..e33bb5da 100644
--- a/Tests/Propel/ClientTest.php
+++ b/Tests/Propel/ClientTest.php
@@ -27,10 +27,10 @@ public function testConstructor()
 
         $types = $client->getAllowedGrantTypes();
         $this->assertCount(1, $types);
-        $this->assertSame(OAuth2::GRANT_TYPE_AUTH_CODE, $types[0]);
+        self::assertSame(OAuth2::GRANT_TYPE_AUTH_CODE, $types[0]);
     }
 
-    public function testCheckSecretWithInvalidArgument()
+    public function testCheckSecretWithInvalidArgument(): void
     {
         $client = new Client();
 
@@ -39,7 +39,7 @@ public function testCheckSecretWithInvalidArgument()
         $this->assertFalse($client->checkSecret(null));
     }
 
-    public function testCheckSecret()
+    public function testCheckSecret(): void
     {
         $client = new Client();
         $client->setSecret('foo');
diff --git a/Tests/Propel/TokenManagerTest.php b/Tests/Propel/TokenManagerTest.php
index bc6f9835..5eeeadb4 100644
--- a/Tests/Propel/TokenManagerTest.php
+++ b/Tests/Propel/TokenManagerTest.php
@@ -38,7 +38,7 @@ public function setUp() : void
 
     public function testConstruct()
     {
-        $this->assertSame(self::TOKEN_CLASS, $this->manager->getClass());
+        self::assertSame(self::TOKEN_CLASS, $this->manager->getClass());
     }
 
     public function testCreateClass()
@@ -100,7 +100,7 @@ public function testFindToken()
         $return = $this->manager->findTokenBy(['token' => '12345']);
 
         $this->assertNotNull($return);
-        $this->assertSame($token, $return);
+        self::assertSame($token, $return);
     }
 
     public function testFindTokenByToken()
@@ -109,7 +109,7 @@ public function testFindTokenByToken()
         $return = $this->manager->findTokenByToken('12345');
 
         $this->assertNotNull($return);
-        $this->assertSame($token, $return);
+        self::assertSame($token, $return);
     }
 
     public function testFindTokenByTokenReturnsNullIfNotFound()
@@ -124,11 +124,11 @@ public function testDeleteExpired()
         $a1 = $this->createToken('12345', time() + 100);
         $a2 = $this->createToken('67890', time() - 100);
 
-        $this->assertSame(2, TokenQuery::create()->count());
+        self::assertSame(2, TokenQuery::create()->count());
 
         $nb = $this->manager->deleteExpired();
 
-        $this->assertSame(1, $nb);
+        self::assertSame(1, $nb);
         $this->assertTrue($a1->equals(TokenQuery::create()->findOne()));
     }
 
diff --git a/Tests/Propel/TokenTest.php b/Tests/Propel/TokenTest.php
index 6ad9e931..5effb30f 100644
--- a/Tests/Propel/TokenTest.php
+++ b/Tests/Propel/TokenTest.php
@@ -28,15 +28,15 @@ class TokenTest extends PropelTestCase
      * @param mixed $expiresAt
      * @param mixed $expect
      */
-    public function testHasExpired($expiresAt, $expect)
+    public function testHasExpired($expiresAt, $expect): void
     {
         $token = new Token();
         $token->setExpiresAt($expiresAt);
 
-        $this->assertSame($expect, $token->hasExpired());
+        self::assertSame($expect, $token->hasExpired());
     }
 
-    public static function getTestHasExpiredData()
+    public static function getTestHasExpiredData(): array
     {
         return [
             [time() + 60, false],
@@ -45,19 +45,19 @@ public static function getTestHasExpiredData()
         ];
     }
 
-    public function testExpiresIn()
+    public function testExpiresIn(): void
     {
         $token = new Token();
 
-        $this->assertSame(PHP_INT_MAX, $token->getExpiresIn());
+        self::assertSame(PHP_INT_MAX, $token->getExpiresIn());
     }
 
-    public function testExpiresInWithExpiresAt()
+    public function testExpiresInWithExpiresAt(): void
     {
         $token = new Token();
         $token->setExpiresAt(time() + 60);
 
-        $this->assertSame(60, $token->getExpiresIn());
+        self::assertSame(60, $token->getExpiresIn());
     }
 }
 
diff --git a/Tests/Security/Authentication/Provider/OAuthProviderTest.php b/Tests/Security/Authentication/Provider/OAuthProviderTest.php
index 885d2007..a14cca65 100644
--- a/Tests/Security/Authentication/Provider/OAuthProviderTest.php
+++ b/Tests/Security/Authentication/Provider/OAuthProviderTest.php
@@ -93,13 +93,13 @@ public function testAuthenticateReturnsTokenIfValid(): void
 
         $result = $this->provider->authenticate($token);
 
-        $this->assertSame($this->user, $result->getUser());
-        $this->assertSame($token->getToken(), $result->getToken());
+        self::assertSame($this->user, $result->getUser());
+        self::assertSame($token->getToken(), $result->getToken());
         $this->assertTrue($result->isAuthenticated());
         $this->assertCount(1, $result->getRoleNames());
 
         $roles = $result->getRoleNames();
-        $this->assertSame('ROLE_USER', $roles[0]);
+        self::assertSame('ROLE_USER', $roles[0]);
     }
 
     public function testAuthenticateReturnsTokenIfValidEvenIfNullData(): void
@@ -144,9 +144,9 @@ public function testAuthenticateTransformsScopesAsRoles(): void
         $roles = $result->getRoleNames();
         $this->assertCount(2, $roles);
         //$this->assertInstanceOf(\Symfony\Component\Security\Core\Role::class, $roles[0]);
-        $this->assertSame('ROLE_FOO', $roles[0]);
+        self::assertSame('ROLE_FOO', $roles[0]);
         //$this->assertInstanceOf(Role::class, $roles[1]);
-        $this->assertSame('ROLE_BAR', $roles[1]);
+        self::assertSame('ROLE_BAR', $roles[1]);
     }
 
     public function testAuthenticateWithNullScope(): void
diff --git a/Tests/Security/Authentification/Token/OAuthTokenTest.php b/Tests/Security/Authentification/Token/OAuthTokenTest.php
index 4e343fbd..d5d5b72f 100644
--- a/Tests/Security/Authentification/Token/OAuthTokenTest.php
+++ b/Tests/Security/Authentification/Token/OAuthTokenTest.php
@@ -31,7 +31,7 @@ public function setUp() : void
         parent::setUp();
     }
 
-    public function testSetTokenWillSetToken()
+    public function testSetTokenWillSetToken(): void
     {
         $token = $this->getMockBuilder(TokenInterface::class)
             ->disableOriginalConstructor()
@@ -39,10 +39,10 @@ public function testSetTokenWillSetToken()
         ;
 
         $this->assertNull($this->instance->setToken($token));
-        $this->assertAttributeSame($token, 'token', $this->instance);
+        self::assertSame($token, $this->instance->getToken());
     }
 
-    public function testGetTokenWillReturnToken()
+    public function testGetTokenWillReturnToken(): void
     {
         $token = $this->getMockBuilder(TokenInterface::class)
             ->disableOriginalConstructor()
@@ -51,10 +51,10 @@ public function testGetTokenWillReturnToken()
 
         $this->assertNull($this->instance->getToken());
         $this->assertNull($this->instance->setToken($token));
-        $this->assertSame($token, $this->instance->getToken());
+        self::assertSame($token, $this->instance->getToken());
     }
 
-    public function testGetCredentialsWillReturnToken()
+    public function testGetCredentialsWillReturnToken(): void
     {
         $token = $this->getMockBuilder(TokenInterface::class)
             ->disableOriginalConstructor()
@@ -63,6 +63,6 @@ public function testGetCredentialsWillReturnToken()
 
         $this->assertNull($this->instance->getCredentials());
         $this->assertNull($this->instance->setToken($token));
-        $this->assertSame($token, $this->instance->getCredentials());
+        self::assertSame($token, $this->instance->getCredentials());
     }
 }
diff --git a/Tests/Security/Firewall/OAuthListenerTest.php b/Tests/Security/Firewall/OAuthListenerTest.php
index 87561c43..22e3aaaf 100644
--- a/Tests/Security/Firewall/OAuthListenerTest.php
+++ b/Tests/Security/Firewall/OAuthListenerTest.php
@@ -17,6 +17,7 @@
 use FOS\OAuthServerBundle\Security\Firewall\OAuthListener;
 use FOS\OAuthServerBundle\Tests\TestCase;
 use OAuth2\OAuth2;
+use PHPUnit\Framework\MockObject\MockObject;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\Event\RequestEvent;
 use Symfony\Component\Security\Core\Authentication\AuthenticationManagerInterface;
@@ -28,6 +29,7 @@ class OAuthListenerTest extends TestCase
 
     protected $authManager;
 
+    /** @var MockObject  */
     protected $securityContext;
 
     protected $event;
@@ -93,7 +95,7 @@ public function testHandle()
         $token = $listener->handle($this->event);
 
         $this->assertInstanceOf(OAuthToken::class, $token);
-        $this->assertSame('a-token', $token->getToken());
+        self::assertSame('a-token', $token->getToken());
     }
 
     public function testHandleResponse()
@@ -130,6 +132,6 @@ public function testHandleResponse()
 
         $ret = $listener->handle($this->event);
 
-        $this->assertSame($response, $ret);
+        self::assertSame($response, $ret);
     }
 }
diff --git a/Tests/Storage/OAuthStorageTest.php b/Tests/Storage/OAuthStorageTest.php
index ef0b4215..f14385c1 100644
--- a/Tests/Storage/OAuthStorageTest.php
+++ b/Tests/Storage/OAuthStorageTest.php
@@ -95,10 +95,10 @@ public function testGetClientReturnsClientWithGivenId()
             ->willReturn($client)
         ;
 
-        $this->assertSame($client, $this->storage->getClient('123_abc'));
+        self::assertSame($client, $this->storage->getClient('123_abc'));
     }
 
-    public function testGetClientReturnsNullIfNotExists()
+    public function testGetClientReturnsNullIfNotExists(): void
     {
         $client = new Client();
 
@@ -111,9 +111,9 @@ public function testGetClientReturnsNullIfNotExists()
         $this->assertNull($this->storage->getClient('123_abc'));
     }
 
-    public function testCheckClientCredentialsThrowsIfInvalidClientClass()
+    public function testCheckClientCredentialsThrowsIfInvalidClientClass(): void
     {
-        $client = $this->getMockBuilder('OAuth2\Model\IOAuth2Client')
+        $client = $this->getMockBuilder(IOAuth2Client::class)
             ->disableOriginalConstructor()
             ->getMock()
         ;
@@ -122,7 +122,7 @@ public function testCheckClientCredentialsThrowsIfInvalidClientClass()
         $this->storage->checkClientCredentials($client, 'dummy');
     }
 
-    public function testCheckClientCredentialsReturnsTrueOnValidCredentials()
+    public function testCheckClientCredentialsReturnsTrueOnValidCredentials(): void
     {
         $client = new Client();
         $client->setSecret('dummy');
@@ -130,7 +130,7 @@ public function testCheckClientCredentialsReturnsTrueOnValidCredentials()
         $this->assertTrue($this->storage->checkClientCredentials($client, 'dummy'));
     }
 
-    public function testCheckClientCredentialsReturnsFalseOnValidCredentials()
+    public function testCheckClientCredentialsReturnsFalseOnValidCredentials(): void
     {
         $client = new Client();
         $client->setSecret('dummy');
@@ -138,7 +138,7 @@ public function testCheckClientCredentialsReturnsFalseOnValidCredentials()
         $this->assertFalse($this->storage->checkClientCredentials($client, 'passe'));
     }
 
-    public function testGetAccessTokenReturnsAccessTokenWithGivenId()
+    public function testGetAccessTokenReturnsAccessTokenWithGivenId(): void
     {
         $token = new AccessToken();
 
@@ -148,10 +148,10 @@ public function testGetAccessTokenReturnsAccessTokenWithGivenId()
             ->willReturn($token)
         ;
 
-        $this->assertSame($token, $this->storage->getAccessToken('123_abc'));
+        self::assertSame($token, $this->storage->getAccessToken('123_abc'));
     }
 
-    public function testGetAccessTokenReturnsNullIfNotExists()
+    public function testGetAccessTokenReturnsNullIfNotExists(): void
     {
         $token = new AccessToken();
 
@@ -164,9 +164,9 @@ public function testGetAccessTokenReturnsNullIfNotExists()
         $this->assertNull($this->storage->getAccessToken('123_abc'));
     }
 
-    public function testCreateAccessTokenThrowsOnInvalidClientClass()
+    public function testCreateAccessTokenThrowsOnInvalidClientClass(): void
     {
-        $client = $this->getMockBuilder('OAuth2\Model\IOAuth2Client')
+        $client = $this->getMockBuilder(IOAuth2Client::class)
             ->disableOriginalConstructor()
             ->getMock()
         ;
@@ -175,7 +175,7 @@ public function testCreateAccessTokenThrowsOnInvalidClientClass()
         $this->storage->createAccessToken('foo', $client, new User(42), 1, 'foo bar');
     }
 
-    public function testCreateAccessToken()
+    public function testCreateAccessToken(): void
     {
         $savedToken = null;
 
@@ -196,17 +196,17 @@ public function testCreateAccessToken()
 
         $token = $this->storage->createAccessToken('foo', $client, $user, 1, 'foo bar');
 
-        $this->assertSame($token, $savedToken);
+        self::assertSame($token, $savedToken);
 
-        $this->assertSame('foo', $token->getToken());
-        $this->assertSame($client, $token->getClient());
-        $this->assertSame($user, $token->getData());
-        $this->assertSame($user, $token->getUser());
-        $this->assertSame(1, $token->getExpiresAt());
-        $this->assertSame('foo bar', $token->getScope());
+        self::assertSame('foo', $token->getToken());
+        self::assertSame($client, $token->getClient());
+        self::assertSame($user, $token->getData());
+        self::assertSame($user, $token->getUser());
+        self::assertSame(1, $token->getExpiresAt());
+        self::assertSame('foo bar', $token->getScope());
     }
 
-    public function testCreateAccessTokenWithoutUser()
+    public function testCreateAccessTokenWithoutUser(): void
     {
         $savedToken = null;
 
@@ -227,10 +227,10 @@ public function testCreateAccessTokenWithoutUser()
 
         $token = $this->storage->createAccessToken('foo', $client, $user, 1, 'foo bar');
 
-        $this->assertSame($token, $savedToken);
+        self::assertSame($token, $savedToken);
     }
 
-    public function testGetRefreshTokenReturnsRefreshTokenWithGivenId()
+    public function testGetRefreshTokenReturnsRefreshTokenWithGivenId(): void
     {
         $token = new RefreshToken();
 
@@ -240,7 +240,7 @@ public function testGetRefreshTokenReturnsRefreshTokenWithGivenId()
             ->willReturn($token)
         ;
 
-        $this->assertSame($token, $this->storage->getRefreshToken('123_abc'));
+        self::assertSame($token, $this->storage->getRefreshToken('123_abc'));
     }
 
     public function testGetRefreshTokenReturnsNullIfNotExists()
@@ -254,7 +254,7 @@ public function testGetRefreshTokenReturnsNullIfNotExists()
         $this->assertNull($this->storage->getRefreshToken('123_abc'));
     }
 
-    public function testCreateRefreshTokenThrowsOnInvalidClientClass()
+    public function testCreateRefreshTokenThrowsOnInvalidClientClass(): void
     {
         $client = $this->getMockBuilder(IOAuth2Client::class)
             ->disableOriginalConstructor()
@@ -265,7 +265,7 @@ public function testCreateRefreshTokenThrowsOnInvalidClientClass()
         $this->storage->createRefreshToken('foo', $client, 42, 1, 'foo bar');
     }
 
-    public function testCreateRefreshToken()
+    public function testCreateRefreshToken(): void
     {
         $savedToken = null;
 
@@ -286,17 +286,17 @@ public function testCreateRefreshToken()
 
         $token = $this->storage->createRefreshToken('foo', $client, $user, 1, 'foo bar');
 
-        $this->assertSame($token, $savedToken);
+        self::assertSame($token, $savedToken);
 
-        $this->assertSame('foo', $token->getToken());
-        $this->assertSame($client, $token->getClient());
-        $this->assertSame($user, $token->getData());
-        $this->assertSame($user, $token->getUser());
-        $this->assertSame(1, $token->getExpiresAt());
-        $this->assertSame('foo bar', $token->getScope());
+        self::assertSame('foo', $token->getToken());
+        self::assertSame($client, $token->getClient());
+        self::assertSame($user, $token->getData());
+        self::assertSame($user, $token->getUser());
+        self::assertSame(1, $token->getExpiresAt());
+        self::assertSame('foo bar', $token->getScope());
     }
 
-    public function testCreateRefreshTokenWithoutUser()
+    public function testCreateRefreshTokenWithoutUser(): void
     {
         $savedToken = null;
 
@@ -317,7 +317,7 @@ public function testCreateRefreshTokenWithoutUser()
 
         $token = $this->storage->createRefreshToken('foo', $client, $user, 1, 'foo bar');
 
-        $this->assertSame($token, $savedToken);
+        self::assertSame($token, $savedToken);
     }
 
     public function testCheckRestrictedGrantTypeThrowsOnInvalidClientClass(): void
@@ -332,7 +332,7 @@ public function testCheckRestrictedGrantTypeThrowsOnInvalidClientClass(): void
         $this->storage->checkRestrictedGrantType($client, 'foo');
     }
 
-    public function testCheckRestrictedGrantType()
+    public function testCheckRestrictedGrantType(): void
     {
         $client = new Client();
         $client->setAllowedGrantTypes(['foo', 'bar']);
@@ -342,7 +342,7 @@ public function testCheckRestrictedGrantType()
         $this->assertFalse($this->storage->checkRestrictedGrantType($client, 'baz'));
     }
 
-    public function testCheckUserCredentialsThrowsOnInvalidClientClass()
+    public function testCheckUserCredentialsThrowsOnInvalidClientClass(): void
     {
         $client = $this->getMockBuilder(IOAuth2Client::class)
             ->disableOriginalConstructor()
@@ -354,7 +354,7 @@ public function testCheckUserCredentialsThrowsOnInvalidClientClass()
         $this->storage->checkUserCredentials($client, 'Joe', 'baz');
     }
 
-    public function testCheckUserCredentialsCatchesAuthenticationExceptions()
+    public function testCheckUserCredentialsCatchesAuthenticationExceptions(): void
     {
         $client = new Client();
 
@@ -370,7 +370,7 @@ public function testCheckUserCredentialsCatchesAuthenticationExceptions()
         $this->assertFalse($result);
     }
 
-    public function testCheckUserCredentialsReturnsTrueOnValidCredentials()
+    public function testCheckUserCredentialsReturnsTrueOnValidCredentials(): void
     {
         $client = new Client();
         $user = $this->getMockBuilder(UserInterface::class)
@@ -404,7 +404,7 @@ public function testCheckUserCredentialsReturnsTrueOnValidCredentials()
             ->willReturn($encoder)
         ;
 
-        $this->assertSame([
+        self::assertSame([
             'data' => $user,
         ], $this->storage->checkUserCredentials($client, 'Joe', 'baz'));
     }
@@ -446,7 +446,7 @@ public function testCheckUserCredentialsReturnsFalseOnInvalidCredentials(): void
         $this->assertFalse($this->storage->checkUserCredentials($client, 'Joe', 'baz'));
     }
 
-    public function testCheckUserCredentialsReturnsFalseIfUserNotExist()
+    public function testCheckUserCredentialsReturnsFalseIfUserNotExist(): void
     {
         $client = new Client();
 
@@ -459,9 +459,9 @@ public function testCheckUserCredentialsReturnsFalseIfUserNotExist()
         $this->assertFalse($this->storage->checkUserCredentials($client, 'Joe', 'baz'));
     }
 
-    public function testCreateAuthCodeThrowsOnInvalidClientClass()
+    public function testCreateAuthCodeThrowsOnInvalidClientClass(): void
     {
-        $client = $this->getMockBuilder('OAuth2\Model\IOAuth2Client')
+        $client = $this->getMockBuilder(IOAuth2Client::class)
             ->disableOriginalConstructor()
             ->getMock()
         ;
@@ -470,7 +470,7 @@ public function testCreateAuthCodeThrowsOnInvalidClientClass()
         $this->storage->createAuthCode('foo', $client, 42, 'http://www.example.com/', 1, 'foo bar');
     }
 
-    public function testCreateAuthCode()
+    public function testCreateAuthCode(): void
     {
         $savedCode = null;
 
@@ -491,17 +491,17 @@ public function testCreateAuthCode()
 
         $code = $this->storage->createAuthCode('foo', $client, $user, 'http://www.example.com/', 1, 'foo bar');
 
-        $this->assertSame($code, $savedCode);
+        self::assertSame($code, $savedCode);
 
-        $this->assertSame('foo', $code->getToken());
-        $this->assertSame($client, $code->getClient());
-        $this->assertSame($user, $code->getData());
-        $this->assertSame($user, $code->getUser());
-        $this->assertSame(1, $code->getExpiresAt());
-        $this->assertSame('foo bar', $code->getScope());
+        self::assertSame('foo', $code->getToken());
+        self::assertSame($client, $code->getClient());
+        self::assertSame($user, $code->getData());
+        self::assertSame($user, $code->getUser());
+        self::assertSame(1, $code->getExpiresAt());
+        self::assertSame('foo bar', $code->getScope());
     }
 
-    public function testGetAuthCodeReturnsAuthCodeWithGivenId()
+    public function testGetAuthCodeReturnsAuthCodeWithGivenId(): void
     {
         $code = new AuthCode();
 
@@ -511,10 +511,10 @@ public function testGetAuthCodeReturnsAuthCodeWithGivenId()
             ->willReturn($code)
         ;
 
-        $this->assertSame($code, $this->storage->getAuthCode('123_abc'));
+        self::assertSame($code, $this->storage->getAuthCode('123_abc'));
     }
 
-    public function testGetAuthCodeReturnsNullIfNotExists()
+    public function testGetAuthCodeReturnsNullIfNotExists(): void
     {
         $this->authCodeManager->expects($this->once())
             ->method('findAuthCodeByToken')
@@ -525,7 +525,7 @@ public function testGetAuthCodeReturnsNullIfNotExists()
         $this->assertNull($this->storage->getAuthCode('123_abc'));
     }
 
-    public function testValidGrantExtension()
+    public function testValidGrantExtension(): void
     {
         $grantExtension = $this->getMockBuilder(GrantExtensionInterface::class)
             ->disableOriginalConstructor()
@@ -552,7 +552,7 @@ public function testValidGrantExtension()
         );
     }
 
-    public function testInvalidGrantExtension()
+    public function testInvalidGrantExtension(): void
     {
         $this->expectException(\OAuth2\OAuth2ServerException::class);
 
@@ -563,7 +563,7 @@ public function testInvalidGrantExtension()
         $this->storage->checkGrantExtension($client, 'https://friendsofsymfony.com/grants/bar', [], []);
     }
 
-    public function testDoubleSetGrantExtension()
+    public function testDoubleSetGrantExtension(): void
     {
         $grantExtension = $this->getMockBuilder(GrantExtensionInterface::class)
             ->disableOriginalConstructor()
@@ -581,10 +581,10 @@ public function testDoubleSetGrantExtension()
         $grantExtensionsProperty->setAccessible(true);
         $grantExtensions = $grantExtensionsProperty->getValue($this->storage);
 
-        $this->assertSame($grantExtension2, $grantExtensions[$uri]);
+        self::assertSame($grantExtension2, $grantExtensions[$uri]);
     }
 
-    public function testMarkAuthCodeAsUsedIfAuthCodeFound()
+    public function testMarkAuthCodeAsUsedIfAuthCodeFound(): void
     {
         $authCode = $this->getMockBuilder(AuthCodeInterface::class)
             ->disableOriginalConstructor()
@@ -606,7 +606,7 @@ public function testMarkAuthCodeAsUsedIfAuthCodeFound()
         $this->storage->markAuthCodeAsUsed('123_abc');
     }
 
-    public function testMarkAuthCodeAsUsedIfAuthCodeNotFound()
+    public function testMarkAuthCodeAsUsedIfAuthCodeNotFound(): void
     {
         $this->authCodeManager->expects($this->atLeastOnce())
             ->method('findAuthCodeByToken')
diff --git a/Tests/Util/RandomTest.php b/Tests/Util/RandomTest.php
index 0e785531..bdab04fa 100644
--- a/Tests/Util/RandomTest.php
+++ b/Tests/Util/RandomTest.php
@@ -58,6 +58,6 @@ public function testGenerateTokenWillUseRandomBytesIfAvailable()
             ->willReturn($baseConvertResult)
         ;
 
-        $this->assertSame($baseConvertResult, Random::generateToken());
+        self::assertSame($baseConvertResult, Random::generateToken());
     }
 }