diff --git a/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php b/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
index 4ffc09f7..9c33906e 100644
--- a/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
+++ b/Tests/DependencyInjection/FOSOAuthServerExtensionTest.php
@@ -23,6 +23,9 @@
 
 class FOSOAuthServerExtensionTest extends \PHPUnit\Framework\TestCase
 {
+    /**
+     * @var ContainerBuilder
+     */
     private $container;
 
     public function setUp()
diff --git a/Tests/Form/Handler/AuthorizeFormHandlerTest.php b/Tests/Form/Handler/AuthorizeFormHandlerTest.php
index dffb6161..f061b515 100644
--- a/Tests/Form/Handler/AuthorizeFormHandlerTest.php
+++ b/Tests/Form/Handler/AuthorizeFormHandlerTest.php
@@ -29,14 +29,25 @@
  */
 class AuthorizeFormHandlerTest extends \PHPUnit\Framework\TestCase
 {
+    /**
+     * @var FormInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $form;
-
+    /**
+     * @var Request&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $request;
-
+    /**
+     * @var ParameterBag&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $requestQuery;
-
+    /**
+     * @var ParameterBag&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $requestRequest;
-
+    /**
+     * @var ContainerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $container;
 
     /**
diff --git a/Tests/Form/Type/AuthorizeFormTypeTest.php b/Tests/Form/Type/AuthorizeFormTypeTest.php
index 2ff1e089..dc11d839 100644
--- a/Tests/Form/Type/AuthorizeFormTypeTest.php
+++ b/Tests/Form/Type/AuthorizeFormTypeTest.php
@@ -100,6 +100,9 @@ public function testGetBlockPrefix()
         $this->assertSame('fos_oauth_server_authorize', $this->instance->getBlockPrefix());
     }
 
+    /**
+     * @return array<object>
+     */
     protected function getTypes()
     {
         return  [
diff --git a/Tests/Functional/AppKernel.php b/Tests/Functional/AppKernel.php
index e97ffc18..bca57e59 100644
--- a/Tests/Functional/AppKernel.php
+++ b/Tests/Functional/AppKernel.php
@@ -41,7 +41,7 @@ public function getCacheDir()
         return sys_get_temp_dir().'/FOSOAuthServerBundle/';
     }
 
-    public function registerContainerConfiguration(LoaderInterface $loader)
+    public function registerContainerConfiguration(LoaderInterface $loader): void
     {
         $loader->load(__DIR__.'/config/config_'.$this->getEnvironment().'.yml');
     }
diff --git a/Tests/Functional/BootTest.php b/Tests/Functional/BootTest.php
index 331f88c0..4e3d56f1 100644
--- a/Tests/Functional/BootTest.php
+++ b/Tests/Functional/BootTest.php
@@ -33,6 +33,9 @@ public function testBoot($env)
         }
     }
 
+    /**
+     * @return array<mixed>
+     */
     public function getTestBootData()
     {
         return [
diff --git a/Tests/Functional/TestBundle/Entity/User.php b/Tests/Functional/TestBundle/Entity/User.php
index 61363bec..f3b24b32 100644
--- a/Tests/Functional/TestBundle/Entity/User.php
+++ b/Tests/Functional/TestBundle/Entity/User.php
@@ -25,15 +25,19 @@ class User implements UserInterface
      * @ORM\Id
      * @ORM\Column(type="integer")
      * @ORM\GeneratedValue(strategy="AUTO")
+     *
+     * @var ?int
      */
     protected $id;
 
     /**
      * @ORM\Column(type="string")
+     *
+     * @var ?string
      */
     protected $password;
 
-    public function getId()
+    public function getId(): ?int
     {
         return $this->id;
     }
@@ -43,18 +47,19 @@ public function getRoles()
         return ['ROLE_USER'];
     }
 
-    public function getPassword()
+    public function getPassword(): ?string
     {
         return $this->password;
     }
 
-    public function setPassword($password)
+    public function setPassword(?string $password): void
     {
         $this->password = $password;
     }
 
     public function getSalt()
     {
+        return null;
     }
 
     public function getUsername()
@@ -62,7 +67,7 @@ public function getUsername()
         return $this->getId();
     }
 
-    public function eraseCredentials()
+    public function eraseCredentials(): void
     {
     }
 }
diff --git a/Tests/Functional/TestCase.php b/Tests/Functional/TestCase.php
index a8e1612f..3061ee51 100644
--- a/Tests/Functional/TestCase.php
+++ b/Tests/Functional/TestCase.php
@@ -35,6 +35,9 @@ protected function tearDown(): void
         static::$kernel = null;
     }
 
+    /**
+     * @param array<mixed> $options
+     */
     protected static function createKernel(array $options = [])
     {
         $env = @$options['env'] ?: 'test';
diff --git a/Tests/Model/TokenTest.php b/Tests/Model/TokenTest.php
index 053032c3..e010cbb1 100644
--- a/Tests/Model/TokenTest.php
+++ b/Tests/Model/TokenTest.php
@@ -38,6 +38,9 @@ public function testHasExpired($expiresAt, $expect)
         $this->assertSame($expect, $token->hasExpired());
     }
 
+    /**
+     * @return array<mixed>
+     */
     public static function getTestHasExpiredData()
     {
         return [
diff --git a/Tests/Security/Authentification/Token/OAuthTokenTest.php b/Tests/Security/Authentification/Token/OAuthTokenTest.php
index 31f41bdb..196d5969 100644
--- a/Tests/Security/Authentification/Token/OAuthTokenTest.php
+++ b/Tests/Security/Authentification/Token/OAuthTokenTest.php
@@ -38,7 +38,7 @@ public function testSetTokenWillSetToken()
         ;
 
         $this->assertNull($this->instance->setToken($token));
-        $this->assertAttributeSame($token, 'token', $this->instance);
+        $this->assertSame($token, $this->instance->getToken());
     }
 
     public function testGetTokenWillReturnToken()
diff --git a/Tests/Security/Firewall/OAuthListenerTest.php b/Tests/Security/Firewall/OAuthListenerTest.php
index 61f62c27..6961b5d2 100644
--- a/Tests/Security/Firewall/OAuthListenerTest.php
+++ b/Tests/Security/Firewall/OAuthListenerTest.php
@@ -23,12 +23,24 @@
 
 class OAuthListenerTest extends TestCase
 {
+    /**
+     * @var OAuth2&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $serverService;
 
+    /**
+     * @var AuthenticationManagerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $authManager;
 
+    /**
+     * @var mixed&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $securityContext;
 
+    /**
+     * @var RequestEvent&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $event;
 
     public function setUp()
diff --git a/Tests/Storage/OAuthStorageTest.php b/Tests/Storage/OAuthStorageTest.php
index f628327b..b8e1c2de 100644
--- a/Tests/Storage/OAuthStorageTest.php
+++ b/Tests/Storage/OAuthStorageTest.php
@@ -29,18 +29,33 @@
 
 class OAuthStorageTest extends \PHPUnit\Framework\TestCase
 {
+    /**
+     * @var ClientManagerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $clientManager;
-
+    /**
+     * @var AccessTokenManagerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $accessTokenManager;
-
+    /**
+     * @var RefreshTokenManagerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $refreshTokenManager;
-
+    /**
+     * @var AuthCodeManagerInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $authCodeManager;
-
+    /**
+     * @var UserProviderInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $userProvider;
-
+    /**
+     * @var EncoderFactoryInterface&\PHPUnit\Framework\MockObject\MockObject
+     */
     protected $encoderFactory;
-
+    /**
+     * @var OAuthStorage
+     */
     protected $storage;
 
     public function setUp()
@@ -605,8 +620,14 @@ public function testMarkAuthCodeAsUsedIfAuthCodeNotFound()
 
 class User implements UserInterface
 {
+    /**
+     * @var string|int
+     */
     private $username;
 
+    /**
+     * @param string|int $username
+     */
     public function __construct($username)
     {
         $this->username = $username;
@@ -614,22 +635,28 @@ public function __construct($username)
 
     public function getRoles()
     {
+        return [];
     }
 
     public function getPassword()
     {
+        return null;
     }
 
     public function getSalt()
     {
+        return null;
     }
 
+    /**
+     * @return string|int
+     */
     public function getUsername()
     {
         return $this->username;
     }
 
-    public function eraseCredentials()
+    public function eraseCredentials(): void
     {
     }
 }