diff --git a/README.md b/README.md
index 898aaf9..bc33259 100644
--- a/README.md
+++ b/README.md
@@ -6,10 +6,6 @@ Yokai Sonata Workflow
 [![Total Downloads](https://poser.pugx.org/yokai/sonata-workflow/downloads)](https://packagist.org/packages/yokai/sonata-workflow)
 [![License](https://poser.pugx.org/yokai/sonata-workflow/license)](https://packagist.org/packages/yokai/sonata-workflow)
 
-[![Build Status](https://api.travis-ci.org/yokai-php/sonata-workflow.png?branch=master)](https://travis-ci.org/yokai-php/sonata-workflow)
-[![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/yokai-php/sonata-workflow/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/yokai-php/sonata-workflow/?branch=master)
-[![Code Coverage](https://scrutinizer-ci.com/g/yokai-php/sonata-workflow/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/yokai-php/sonata-workflow/?branch=master)
-
 
 Introduction
 ------------
@@ -44,38 +40,6 @@ Configuration
 
 Let say that you have an entity named `PullRequest` that is under workflow and for which you have an admin.
 
-#### symfony/workflow <4.3
-```yaml
-# config/packages/workflow.yml
-framework:
-    workflows:
-        pull_request:
-            type: state_machine
-            marking_store:
-                type: single_state
-                arguments:
-                    - status
-            supports:
-                - App\Entity\PullRequest
-            places:
-                - opened
-                - pending_review
-                - merged
-                - closed
-            initial_place: opened
-            transitions:
-                start_review:
-                    from: opened
-                    to:   pending_review
-                merge:
-                    from: pending_review
-                    to:   merged
-                close:
-                    from: pending_review
-                    to:   closed
-```
-
-#### symfony/workflow ^4.3|^5.0
 ```yaml
 # config/packages/workflow.yml
 framework:
@@ -224,18 +188,21 @@ services:
 <?php
 // src/Admin/Controller/PullRequestController.php
 
+declare(strict_types=1);
+
 namespace App\Admin\Controller;
 
 use App\Entity\PullRequest;
 use App\Form\PullRequest\StartReviewType;
 use Sonata\AdminBundle\Controller\CRUDController;
+use Symfony\Component\HttpFoundation\Response;
 use Yokai\SonataWorkflow\Controller\WorkflowControllerTrait;
 
 class PullRequestController extends CRUDController
 {
     use WorkflowControllerTrait;
 
-    protected function preApplyTransition($object, $transition)
+    protected function preApplyTransition($object, string $transition): ?Response
     {
         switch ($transition) {
             case 'start_review':
@@ -245,7 +212,7 @@ class PullRequestController extends CRUDController
         return null;
     }
 
-    protected function startReview(PullRequest $object, $transition)
+    protected function startReview(PullRequest $object, string $transition): ?Response
     {
         $form = $this->createForm(
             StartReviewType::class,
diff --git a/composer.json b/composer.json
index fb64114..ac5b4b8 100644
--- a/composer.json
+++ b/composer.json
@@ -25,12 +25,12 @@
     }
   },
   "require": {
-    "php": "^5.6|^7.0",
+    "php": "^7.1",
     "sonata-project/admin-bundle": "^3.0",
-    "symfony/workflow": "^3.2|^4.0|^5.0"
+    "symfony/workflow": "^4.4|^5.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^5.0",
+    "phpunit/phpunit": "^7.5",
     "squizlabs/php_codesniffer": "^3.5"
   },
   "minimum-stability": "stable",
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
index 3d26c56..b25a8a1 100644
--- a/phpcs.xml.dist
+++ b/phpcs.xml.dist
@@ -11,6 +11,7 @@
     <rule ref="PSR12"/>
 
     <file>src/</file>
+    <file>tests/</file>
 
     <rule ref="Generic.PHP.ForbiddenFunctions">
         <properties>
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 0c1c221..9f8bda0 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -7,7 +7,6 @@
          convertWarningsToExceptions="true"
          processIsolation="false"
          stopOnFailure="false"
-         syntaxCheck="false"
          colors="true"
          bootstrap="vendor/autoload.php"
         >
diff --git a/src/Admin/Extension/WorkflowExtension.php b/src/Admin/Extension/WorkflowExtension.php
index 67831ac..b037588 100644
--- a/src/Admin/Extension/WorkflowExtension.php
+++ b/src/Admin/Extension/WorkflowExtension.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Admin\Extension;
 
 use Knp\Menu\ItemInterface as MenuItemInterface;
@@ -42,7 +44,7 @@ public function __construct(Registry $registry, array $options = [])
     /**
      * @inheritdoc
      */
-    public function configureRoutes(AdminInterface $admin, RouteCollection $collection)
+    public function configureRoutes(AdminInterface $admin, RouteCollection $collection): void
     {
         $collection->add(
             'workflow_apply_transition',
@@ -53,7 +55,7 @@ public function configureRoutes(AdminInterface $admin, RouteCollection $collecti
     /**
      * @inheritdoc
      */
-    public function alterNewInstance(AdminInterface $admin, $object)
+    public function alterNewInstance(AdminInterface $admin, $object): void
     {
         try {
             $workflow = $this->getWorkflow($object, $this->options['workflow_name']);
@@ -72,7 +74,7 @@ public function configureSideMenu(
         MenuItemInterface $menu,
         $action,
         AdminInterface $childAdmin = null
-    ) {
+    ): void {
         if (null !== $childAdmin || !in_array($action, $this->options['render_actions'], true)) {
             return;
         }
@@ -100,7 +102,7 @@ public function configureSideMenu(
     /**
      * @inheritdoc
      */
-    public function getAccessMapping(AdminInterface $admin)
+    public function getAccessMapping(AdminInterface $admin): array
     {
         return [
             'viewTransitions' => $this->options['view_transitions_role'],
@@ -115,7 +117,7 @@ public function getAccessMapping(AdminInterface $admin)
      * @return Workflow
      * @throws InvalidArgumentException
      */
-    protected function getWorkflow($subject, $workflowName = null)
+    protected function getWorkflow($subject, string $workflowName = null): Workflow
     {
         return $this->registry->get($subject, $workflowName);
     }
@@ -123,7 +125,7 @@ protected function getWorkflow($subject, $workflowName = null)
     /**
      * @param OptionsResolver $resolver
      */
-    protected function configureOptions(OptionsResolver $resolver)
+    protected function configureOptions(OptionsResolver $resolver): void
     {
         $resolver
             ->setDefaults([
@@ -157,7 +159,7 @@ protected function configureOptions(OptionsResolver $resolver)
      * @param MenuItemInterface $menu
      * @param AdminInterface    $admin
      */
-    protected function noTransitions(MenuItemInterface $menu, AdminInterface $admin)
+    protected function noTransitions(MenuItemInterface $menu, AdminInterface $admin): void
     {
         if ($this->options['no_transition_display']) {
             $menu->addChild($this->options['no_transition_label'], [
@@ -173,13 +175,17 @@ protected function noTransitions(MenuItemInterface $menu, AdminInterface $admin)
     }
 
     /**
-     * @param MenuItemInterface $menu
-     * @param AdminInterface    $admin
-     * @param Transition[]      $transitions
-     * @param object            $subject
+     * @param MenuItemInterface     $menu
+     * @param AdminInterface        $admin
+     * @param iterable|Transition[] $transitions
+     * @param object                $subject
      */
-    protected function transitionsDropdown(MenuItemInterface $menu, AdminInterface $admin, $transitions, $subject)
-    {
+    protected function transitionsDropdown(
+        MenuItemInterface $menu,
+        AdminInterface $admin,
+        iterable $transitions,
+        $subject
+    ): void {
         $workflowMenu = $menu->addChild($this->options['dropdown_transitions_label'], [
             'attributes' => [
                 'dropdown' => true,
@@ -201,8 +207,12 @@ protected function transitionsDropdown(MenuItemInterface $menu, AdminInterface $
      * @param Transition        $transition
      * @param object            $subject
      */
-    protected function transitionsItem(MenuItemInterface $menu, AdminInterface $admin, Transition $transition, $subject)
-    {
+    protected function transitionsItem(
+        MenuItemInterface $menu,
+        AdminInterface $admin,
+        Transition $transition,
+        $subject
+    ): void {
         $options = [
             'attributes' => [],
             'extras' => [
@@ -229,7 +239,7 @@ protected function transitionsItem(MenuItemInterface $menu, AdminInterface $admi
      *
      * @return string|null
      */
-    protected function getTransitionIcon(Transition $transition)
+    protected function getTransitionIcon(Transition $transition): ?string
     {
         if (isset($this->options['transitions_icons'][$transition->getName()])) {
             return $this->options['transitions_icons'][$transition->getName()];
@@ -245,7 +255,7 @@ protected function getTransitionIcon(Transition $transition)
      *
      * @return string
      */
-    protected function generateTransitionUri(AdminInterface $admin, Transition $transition, $subject)
+    protected function generateTransitionUri(AdminInterface $admin, Transition $transition, $subject): string
     {
         return $admin->generateObjectUrl(
             'workflow_apply_transition',
@@ -260,7 +270,7 @@ protected function generateTransitionUri(AdminInterface $admin, Transition $tran
      *
      * @return bool
      */
-    protected function isGrantedView(AdminInterface $admin, $subject)
+    protected function isGrantedView(AdminInterface $admin, $subject): bool
     {
         try {
             $admin->checkAccess('viewTransitions', $subject);
@@ -277,7 +287,7 @@ protected function isGrantedView(AdminInterface $admin, $subject)
      *
      * @return bool
      */
-    protected function isGrantedApply(AdminInterface $admin, $subject)
+    protected function isGrantedApply(AdminInterface $admin, $subject): bool
     {
         try {
             $admin->checkAccess('applyTransitions', $subject);
diff --git a/src/Controller/WorkflowController.php b/src/Controller/WorkflowController.php
index 35406c7..936101f 100644
--- a/src/Controller/WorkflowController.php
+++ b/src/Controller/WorkflowController.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Controller;
 
 use Sonata\AdminBundle\Controller\CRUDController;
diff --git a/src/Controller/WorkflowControllerTrait.php b/src/Controller/WorkflowControllerTrait.php
index 76d9a12..be77a58 100644
--- a/src/Controller/WorkflowControllerTrait.php
+++ b/src/Controller/WorkflowControllerTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Controller;
 
 use Psr\Container\ContainerInterface;
@@ -43,7 +45,7 @@ trait WorkflowControllerTrait
      *
      * @required Symfony DI autowiring
      */
-    public function setWorkflowRegistry(Registry $workflowRegistry)
+    public function setWorkflowRegistry(Registry $workflowRegistry): void
     {
         $this->workflowRegistry = $workflowRegistry;
     }
@@ -53,7 +55,7 @@ public function setWorkflowRegistry(Registry $workflowRegistry)
      *
      * @return Response
      */
-    public function workflowApplyTransitionAction(Request $request)
+    public function workflowApplyTransitionAction(Request $request): Response
     {
         $id = $request->get($this->admin->getIdParameter());
 
@@ -153,7 +155,7 @@ public function workflowApplyTransitionAction(Request $request)
      * @return Workflow
      * @throws InvalidArgumentException
      */
-    protected function getWorkflow($object)
+    protected function getWorkflow($object): Workflow
     {
         $registry = $this->workflowRegistry;
         if ($registry === null) {
@@ -183,7 +185,7 @@ protected function getWorkflow($object)
      *
      * @return null|Response
      */
-    protected function preApplyTransition($object, $transition)
+    protected function preApplyTransition($object, string $transition): ?Response
     {
         return null;
     }
diff --git a/tests/Admin/Extension/WorkflowExtensionTest.php b/tests/Admin/Extension/WorkflowExtensionTest.php
index 3cd173a..f77b931 100644
--- a/tests/Admin/Extension/WorkflowExtensionTest.php
+++ b/tests/Admin/Extension/WorkflowExtensionTest.php
@@ -1,9 +1,13 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Tests\Admin\Extension;
 
+use Generator;
 use Knp\Menu\MenuFactory;
 use Knp\Menu\MenuItem;
+use PHPUnit\Framework\TestCase;
 use Prophecy\Prophecy\ObjectProphecy;
 use Sonata\AdminBundle\Admin\AdminInterface;
 use Sonata\AdminBundle\Route\RouteCollection;
@@ -13,16 +17,15 @@
 use Symfony\Component\Workflow\Registry;
 use Symfony\Component\Workflow\StateMachine;
 use Yokai\SonataWorkflow\Admin\Extension\WorkflowExtension;
-use Yokai\SonataWorkflow\Tests\Fixtures\LegacyWorkflowRegistry;
 use Yokai\SonataWorkflow\Controller\WorkflowController;
 use Yokai\SonataWorkflow\Tests\PullRequest;
 
 /**
  * @author Yann Eugoné <eugone.yann@gmail.com>
  */
-class WorkflowExtensionTest extends \PHPUnit_Framework_TestCase
+class WorkflowExtensionTest extends TestCase
 {
-    public function testConfigureRoutes()
+    public function testConfigureRoutes(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -43,7 +46,7 @@ public function testConfigureRoutes()
         self::assertSame('pull_request', $defaults['_sonata_admin']);
     }
 
-    public function testAlterNewInstanceWithoutWorkflow()
+    public function testAlterNewInstanceWithoutWorkflow(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -54,13 +57,13 @@ public function testAlterNewInstanceWithoutWorkflow()
         self::assertNull($pullRequest->getMarking());
     }
 
-    public function testAlterNewInstance()
+    public function testAlterNewInstance(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
 
-        $registry = new LegacyWorkflowRegistry();
-        $registry->add(
+        $registry = new Registry();
+        $registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -71,7 +74,7 @@ public function testAlterNewInstance()
         self::assertSame('opened', $pullRequest->getMarking());
     }
 
-    public function testAccessMapping()
+    public function testAccessMapping(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -83,7 +86,7 @@ public function testAccessMapping()
         );
     }
 
-    public function testConfigureSideMenuWithoutSubject()
+    public function testConfigureSideMenuWithoutSubject(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -95,7 +98,7 @@ public function testConfigureSideMenuWithoutSubject()
         self::assertFalse($menu->hasChildren());
     }
 
-    public function testConfigureSideMenuWithoutPermission()
+    public function testConfigureSideMenuWithoutPermission(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -108,7 +111,7 @@ public function testConfigureSideMenuWithoutPermission()
         self::assertFalse($menu->hasChildren());
     }
 
-    public function testConfigureSideMenuWithoutWorkflow()
+    public function testConfigureSideMenuWithoutWorkflow(): void
     {
         /** @var AdminInterface|ObjectProphecy $admin */
         $admin = $this->prophesize(AdminInterface::class);
@@ -124,7 +127,7 @@ public function testConfigureSideMenuWithoutWorkflow()
     /**
      * @dataProvider markingToTransition
      */
-    public function testConfigureSideMenu($marking, array $transitions, $grantedApply)
+    public function testConfigureSideMenu(string $marking, array $transitions, bool $grantedApply): void
     {
         $pullRequest = new PullRequest();
         $pullRequest->setMarking($marking);
@@ -147,19 +150,19 @@ public function testConfigureSideMenu($marking, array $transitions, $grantedAppl
         foreach ($transitions as $transition) {
             $labelStrategy->getLabel($transition, 'workflow', 'transition')
                 ->shouldBeCalledTimes(1)
-                ->willReturn('workflow.transition.'.$transition);
+                ->willReturn('workflow.transition.' . $transition);
             if ($grantedApply) {
                 $admin->generateObjectUrl('workflow_apply_transition', $pullRequest, ['transition' => $transition])
                     ->shouldBeCalledTimes(1)
-                    ->willReturn('/pull-request/42/workflow/transition/'.$transition.'/apply');
+                    ->willReturn('/pull-request/42/workflow/transition/' . $transition . '/apply');
             } else {
                 $admin->generateObjectUrl('workflow_apply_transition', $pullRequest, ['transition' => $transition])
                     ->shouldNotBeCalled();
             }
         }
 
-        $registry = new LegacyWorkflowRegistry();
-        $registry->add(
+        $registry = new Registry();
+        $registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -192,9 +195,9 @@ public function testConfigureSideMenu($marking, array $transitions, $grantedAppl
                     $icon = 'fa fa-times';
                 }
 
-                self::assertNotNull($item = $child->getChild('workflow.transition.'.$transition));
+                self::assertNotNull($item = $child->getChild('workflow.transition.' . $transition));
                 if ($grantedApply) {
-                    self::assertSame('/pull-request/42/workflow/transition/'.$transition.'/apply', $item->getUri());
+                    self::assertSame('/pull-request/42/workflow/transition/' . $transition . '/apply', $item->getUri());
                 } else {
                     self::assertNull($item->getUri());
                 }
@@ -204,14 +207,14 @@ public function testConfigureSideMenu($marking, array $transitions, $grantedAppl
         }
     }
 
-    public function markingToTransition()
+    public function markingToTransition(): Generator
     {
         foreach ([true, false] as $grantedApply) {
             $grantedApplyStr = $grantedApply ? 'with links' : 'without links';
 
-            yield 'opened '.$grantedApplyStr => ['opened', ['start_review'], $grantedApply];
-            yield 'pending_review '.$grantedApplyStr => ['pending_review', ['merge', 'close'], $grantedApply];
-            yield 'closed '.$grantedApplyStr => ['closed', [], $grantedApply];
+            yield 'opened ' . $grantedApplyStr => ['opened', ['start_review'], $grantedApply];
+            yield 'pending_review ' . $grantedApplyStr => ['pending_review', ['merge', 'close'], $grantedApply];
+            yield 'closed ' . $grantedApplyStr => ['closed', [], $grantedApply];
         }
     }
 }
diff --git a/tests/Controller/WorkflowControllerTest.php b/tests/Controller/WorkflowControllerTest.php
index 0219bde..a5a9a38 100644
--- a/tests/Controller/WorkflowControllerTest.php
+++ b/tests/Controller/WorkflowControllerTest.php
@@ -1,7 +1,10 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Tests\Controller;
 
+use PHPUnit\Framework\TestCase;
 use Prophecy\Prophecy\ObjectProphecy;
 use Sonata\AdminBundle\Admin\AdminInterface;
 use Sonata\AdminBundle\Admin\Pool;
@@ -17,9 +20,10 @@
 use Symfony\Component\HttpFoundation\Session\Flash\FlashBag;
 use Symfony\Component\HttpFoundation\Session\Session;
 use Symfony\Component\HttpFoundation\Session\Storage\MockArraySessionStorage;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\Workflow\Registry;
 use Symfony\Component\Workflow\StateMachine;
-use Yokai\SonataWorkflow\Tests\Fixtures\LegacyWorkflowRegistry;
 use Yokai\SonataWorkflow\Tests\Fixtures\StubTranslator;
 use Yokai\SonataWorkflow\Tests\PullRequest;
 use Yokai\SonataWorkflow\Tests\PullRequestWorkflowController;
@@ -28,7 +32,7 @@
 /**
  * @author Yann Eugoné <eugone.yann@gmail.com>
  */
-class WorkflowControllerTest extends \PHPUnit_Framework_TestCase
+class WorkflowControllerTest extends TestCase
 {
     /**
      * @var ContainerInterface|ObjectProphecy
@@ -55,18 +59,13 @@ class WorkflowControllerTest extends \PHPUnit_Framework_TestCase
      */
     private $flashBag;
 
-    /**
-     * @var StubTranslator
-     */
-    private $translator;
-
     public function setUp()
     {
         $this->container = $this->prophesize(ContainerInterface::class);
         $this->admin = $this->prophesize(AdminInterface::class);
-        $this->registry = new LegacyWorkflowRegistry();
+        $this->registry = new Registry();
         $this->flashBag = new FlashBag();
-        $this->translator = new StubTranslator();
+        $translator = new StubTranslator();
 
         $stack = new RequestStack();
         $stack->push($this->request = new Request());
@@ -83,10 +82,12 @@ public function setUp()
         $this->container->get('workflow.registry')->willReturn($this->registry);
         $this->container->get('kernel')->willReturn(new TestKernel());
         $this->container->has('session')->willReturn(true);
-        $this->container->get('session')->willReturn(new Session(new MockArraySessionStorage(), null, $this->flashBag));
-        $this->container->get('translator')->willReturn($this->translator);
+        $this->container->get('session')
+            ->willReturn(new Session(new MockArraySessionStorage(), null, $this->flashBag));
+        $this->container->get('translator')->willReturn($translator);
         $this->container->has('logger')->willReturn(false);
-        $this->container->get('admin.pull_request.template_registry')->willReturn($this->prophesize(TemplateRegistryInterface::class)->reveal());
+        $this->container->get('admin.pull_request.template_registry')
+            ->willReturn($this->prophesize(TemplateRegistryInterface::class)->reveal());
 
         $this->admin->isChild()->willReturn(false);
         $this->admin->setRequest($this->request)->willReturn(null);
@@ -94,34 +95,22 @@ public function setUp()
         $this->admin->getCode()->willReturn('admin.pull_request');
     }
 
-    public function tearDown()
+    public function testWorkflowApplyTransitionActionObjectNotFound(): void
     {
-        $this->container =
-        $this->request =
-        $this->admin =
-        $this->registry =
-        $this->flashBag =
-        $this->translator = null;
-    }
+        $this->expectException(NotFoundHttpException::class);
+        $this->expectExceptionMessage('unable to find the object with id: 42');
 
-    /**
-     * @expectedException \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
-     * @expectedExceptionMessage unable to find the object with id: 42
-     */
-    public function testWorkflowApplyTransitionActionObjectNotFound()
-    {
         $this->admin->getObject(42)->shouldBeCalledTimes(1)
             ->willReturn(null);
 
         $this->controller()->workflowApplyTransitionAction($this->request);
     }
 
-    /**
-     * @expectedException \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
-     * @expectedExceptionMessage Not found
-     */
-    public function testWorkflowApplyTransitionActionWorkflowNotFound()
+    public function testWorkflowApplyTransitionActionWorkflowNotFound(): void
     {
+        $this->expectException(NotFoundHttpException::class);
+        $this->expectExceptionMessage('Not found');
+
         $this->admin->getObject(42)->shouldBeCalledTimes(1)
             ->willReturn($subject = new PullRequest());
         $this->admin->setSubject($subject)->shouldBeCalledTimes(1);
@@ -131,13 +120,12 @@ public function testWorkflowApplyTransitionActionWorkflowNotFound()
         $this->controller()->workflowApplyTransitionAction($this->request);
     }
 
-    /**
-     * @expectedException \Symfony\Component\HttpKernel\Exception\BadRequestHttpException
-     * @expectedExceptionMessage missing transition to apply
-     */
-    public function testWorkflowApplyTransitionActionMissingTransition()
+    public function testWorkflowApplyTransitionActionMissingTransition(): void
     {
-        $this->registry->add(
+        $this->expectException(BadRequestHttpException::class);
+        $this->expectExceptionMessage('missing transition to apply');
+
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -151,13 +139,12 @@ public function testWorkflowApplyTransitionActionMissingTransition()
         $this->controller()->workflowApplyTransitionAction($this->request);
     }
 
-    /**
-     * @expectedException \Symfony\Component\HttpKernel\Exception\BadRequestHttpException
-     * @expectedExceptionMessage transition transition_that_do_not_exists could not be applied to object pr42
-     */
-    public function testWorkflowApplyTransitionActionTransitionException()
+    public function testWorkflowApplyTransitionActionTransitionException(): void
     {
-        $this->registry->add(
+        $this->expectException(BadRequestHttpException::class);
+        $this->expectExceptionMessage('transition transition_that_do_not_exists could not be applied to object pr42');
+
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -174,13 +161,12 @@ public function testWorkflowApplyTransitionActionTransitionException()
         $this->controller()->workflowApplyTransitionAction($this->request);
     }
 
-    /**
-     * @expectedException \Sonata\AdminBundle\Exception\ModelManagerException
-     * @expectedExceptionMessage phpunit error
-     */
-    public function testWorkflowApplyTransitionActionModelManagerException()
+    public function testWorkflowApplyTransitionActionModelManagerException(): void
     {
-        $this->registry->add(
+        $this->expectException(ModelManagerException::class);
+        $this->expectExceptionMessage('phpunit error');
+
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -199,9 +185,9 @@ public function testWorkflowApplyTransitionActionModelManagerException()
         $this->controller()->workflowApplyTransitionAction($this->request);
     }
 
-    public function testWorkflowApplyTransitionActionLockException()
+    public function testWorkflowApplyTransitionActionLockException(): void
     {
-        $this->registry->add(
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -235,9 +221,9 @@ public function testWorkflowApplyTransitionActionLockException()
         self::assertSame('[trans]flash_lock_error[/trans]', $errors[0]);
     }
 
-    public function testWorkflowApplyTransitionActionSuccessXmlHttp()
+    public function testWorkflowApplyTransitionActionSuccessXmlHttp(): void
     {
-        $this->registry->add(
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -264,9 +250,9 @@ public function testWorkflowApplyTransitionActionSuccessXmlHttp()
         self::assertCount(0, $errors);
     }
 
-    public function testWorkflowApplyTransitionActionSuccessHttp()
+    public function testWorkflowApplyTransitionActionSuccessHttp(): void
     {
-        $this->registry->add(
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -300,9 +286,9 @@ public function testWorkflowApplyTransitionActionSuccessHttp()
         self::assertSame('[trans]flash_edit_success[/trans]', $successes[0]);
     }
 
-    public function testWorkflowApplyTransitionActionPreApply()
+    public function testWorkflowApplyTransitionActionPreApply(): void
     {
-        $this->registry->add(
+        $this->registry->addWorkflow(
             new StateMachine(PullRequest::createWorkflowDefinition()),
             PullRequest::createSupportStrategy()
         );
@@ -330,7 +316,7 @@ public function testWorkflowApplyTransitionActionPreApply()
         self::assertCount(0, $successes);
     }
 
-    private function controller()
+    private function controller(): PullRequestWorkflowController
     {
         $controller = new PullRequestWorkflowController();
 
diff --git a/tests/Fixtures/LegacyWorkflowRegistry.php b/tests/Fixtures/LegacyWorkflowRegistry.php
deleted file mode 100644
index 497aa52..0000000
--- a/tests/Fixtures/LegacyWorkflowRegistry.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Yokai\SonataWorkflow\Tests\Fixtures;
-
-use Symfony\Component\Workflow\Registry;
-use Symfony\Component\Workflow\Workflow;
-
-/**
- * This class is provided in order to allow tests to call `add()` method, which
- * is deprecated since symfony/workflow 4.1 and was removed in version 5.0.
- */
-final class LegacyWorkflowRegistry extends Registry
-{
-    public function add(Workflow $workflow, $supportStrategy)
-    {
-        if (method_exists($this, 'addWorkflow')) {
-            $this->addWorkflow($workflow, $supportStrategy);
-
-            return;
-        }
-
-        parent::add($workflow, $supportStrategy);
-    }
-}
diff --git a/tests/Fixtures/StubTranslator.php b/tests/Fixtures/StubTranslator.php
index 90d56bf..dacaa02 100644
--- a/tests/Fixtures/StubTranslator.php
+++ b/tests/Fixtures/StubTranslator.php
@@ -4,39 +4,12 @@
 
 namespace Yokai\SonataWorkflow\Tests\Fixtures;
 
-use Symfony\Component\Translation\TranslatorInterface as LegacyTranslatorInterface;
 use Symfony\Contracts\Translation\TranslatorInterface;
 
-/**
- * `StubTranslator` provides a simple implementation for the "translator" service.
- */
-if (interface_exists(TranslatorInterface::class)) {
-    final class StubTranslator implements TranslatorInterface
+final class StubTranslator implements TranslatorInterface
+{
+    public function trans($id, array $parameters = [], $domain = null, $locale = null): string
     {
-        public function trans($id, array $parameters = [], $domain = null, $locale = null): string
-        {
-            return '[trans]'.strtr($id, $parameters).'[/trans]';
-        }
-    }
-} else {
-    final class StubTranslator implements LegacyTranslatorInterface
-    {
-        public function trans($id, array $parameters = [], $domain = null, $locale = null)
-        {
-            return '[trans]'.$id.'[/trans]';
-        }
-
-        public function transChoice($id, $number, array $parameters = [], $domain = null, $locale = null)
-        {
-            return '[trans]'.$id.'[/trans]';
-        }
-
-        public function setLocale($locale)
-        {
-        }
-
-        public function getLocale()
-        {
-        }
+        return '[trans]' . strtr($id, $parameters) . '[/trans]';
     }
 }
diff --git a/tests/PullRequest.php b/tests/PullRequest.php
index 8af6b04..9e8adb0 100644
--- a/tests/PullRequest.php
+++ b/tests/PullRequest.php
@@ -1,27 +1,29 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Tests;
 
 use Symfony\Component\Workflow\Definition;
-use Symfony\Component\Workflow\SupportStrategy\ClassInstanceSupportStrategy;
 use Symfony\Component\Workflow\SupportStrategy\InstanceOfSupportStrategy;
+use Symfony\Component\Workflow\SupportStrategy\WorkflowSupportStrategyInterface;
 use Symfony\Component\Workflow\Transition;
 
 class PullRequest
 {
     private $marking;
 
-    public function getMarking()
+    public function getMarking(): ?string
     {
         return $this->marking;
     }
 
-    public function setMarking($marking)
+    public function setMarking(string $marking): void
     {
         $this->marking = $marking;
     }
 
-    public static function createWorkflowDefinition()
+    public static function createWorkflowDefinition(): Definition
     {
         return new Definition(
             ['opened', 'pending_review', 'merged', 'closed'],
@@ -34,12 +36,8 @@ public static function createWorkflowDefinition()
         );
     }
 
-    public static function createSupportStrategy()
+    public static function createSupportStrategy(): WorkflowSupportStrategyInterface
     {
-        if (class_exists(InstanceOfSupportStrategy::class)) {
-            return new InstanceOfSupportStrategy(__CLASS__);
-        }
-
-        return new ClassInstanceSupportStrategy(__CLASS__);
+        return new InstanceOfSupportStrategy(__CLASS__);
     }
 }
diff --git a/tests/PullRequestWorkflowController.php b/tests/PullRequestWorkflowController.php
index 67b4c2a..9237cd5 100644
--- a/tests/PullRequestWorkflowController.php
+++ b/tests/PullRequestWorkflowController.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Tests;
 
 use Symfony\Component\HttpFoundation\Response;
@@ -7,7 +9,7 @@
 
 class PullRequestWorkflowController extends WorkflowController
 {
-    protected function preApplyTransition($object, $transition)
+    protected function preApplyTransition($object, string $transition): ?Response
     {
         if ($transition === 'merge') {
             return new Response('merge');
diff --git a/tests/TestKernel.php b/tests/TestKernel.php
index 19623d3..0f60610 100644
--- a/tests/TestKernel.php
+++ b/tests/TestKernel.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yokai\SonataWorkflow\Tests;
 
 use Symfony\Component\Config\Loader\LoaderInterface;
@@ -12,11 +14,11 @@ public function __construct()
         parent::__construct('test', true);
     }
 
-    public function registerBundles()
+    public function registerBundles(): void
     {
     }
 
-    public function registerContainerConfiguration(LoaderInterface $loader)
+    public function registerContainerConfiguration(LoaderInterface $loader): void
     {
     }
 }