diff --git a/tests/Service/NotificationServiceTest.php b/tests/Service/NotificationServiceTest.php
new file mode 100644
index 0000000..6419f03
--- /dev/null
+++ b/tests/Service/NotificationServiceTest.php
@@ -0,0 +1,239 @@
+<?php
+
+namespace App\Tests\Service;
+
+use App\Entity\Organizations;
+use App\Entity\User;
+use App\Message\NotificationMessage;
+use App\Service\NotificationService;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\MessageBusInterface;
+
+class NotificationServiceTest extends TestCase
+{
+    private NotificationService $service;
+    private MockObject|MessageBusInterface $messageBus;
+
+    protected function setUp(): void
+    {
+        $this->messageBus = $this->createMock(MessageBusInterface::class);
+        $this->service = new NotificationService($this->messageBus);
+    }
+
+    /**
+     * Helper to inject IDs into entities without setters.
+     * Prevents "getId() on null" errors since we are not using a real DB.
+     */
+    private function setEntityId(object $entity, int $id): void
+    {
+        $reflection = new \ReflectionClass($entity);
+        if ($reflection->hasProperty('id')) {
+            $property = $reflection->getProperty('id');
+            // $property->setAccessible(true); // Uncomment if using PHP < 8.1
+            $property->setValue($entity, $id);
+        }
+    }
+
+    public function testNotifyUserInvited(): void
+    {
+        // 1. Setup Data
+        $recipient = new User();
+        $this->setEntityId($recipient, 1);
+
+        $invitedUser = new User();
+        $this->setEntityId($invitedUser, 2);
+        $invitedUser->setName('John');
+        $invitedUser->setSurname('Doe');
+        $invitedUser->setEmail('john@doe.com');
+
+        $org = new Organizations();
+        $this->setEntityId($org, 100);
+        $org->setName('Acme Corp');
+
+        // 2. Expect Dispatch
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                // Verify the content of the dispatched message object
+                return $message->getType() === NotificationService::TYPE_USER_INVITED
+                    && $message->getTitle() === 'Invitation envoyée'
+                    && str_contains($message->getMessage(), 'John Doe a été invité à rejoindre Acme Corp')
+                    && $message->getData()['userEmail'] === 'john@doe.com'
+                    && $message->getOrganizationId() === 100;
+            }))
+            ->willReturn(new Envelope(new \stdClass())); // Dispatch returns an Envelope
+
+        // 3. Run
+        $this->service->notifyUserInvited($recipient, $invitedUser, $org);
+    }
+
+    public function testNotifyUserAcceptedInvite(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $acceptedUser = new User(); $this->setEntityId($acceptedUser, 2);
+        $acceptedUser->setName('Jane');
+        $acceptedUser->setSurname('Smith');
+        $acceptedUser->setEmail('jane@smith.com');
+
+        $org = new Organizations(); $this->setEntityId($org, 200);
+        $org->setName('TechGlobal');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_USER_ACCEPTED
+                    && $message->getTitle() === 'Invitation acceptée'
+                    && str_contains($message->getMessage(), 'Jane Smith a accepté l\'invitation à TechGlobal')
+                    && $message->getData()['organizationName'] === 'TechGlobal';
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyUserAcceptedInvite($recipient, $acceptedUser, $org);
+    }
+
+    public function testNotifyUserDeactivated(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $removedUser = new User(); $this->setEntityId($removedUser, 3);
+        $removedUser->setName('Bob');
+        $removedUser->setSurname('Builder');
+
+        $org = new Organizations(); $this->setEntityId($org, 300);
+        $org->setName('BuildIt');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_USER_DEACTIVATED
+                    && $message->getTitle() === 'Membre retiré'
+                    && str_contains($message->getMessage(), 'Bob Builder a été désactivé de BuildIt')
+                    && $message->getData()['userId'] === 3;
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyUserDeactivated($recipient, $removedUser, $org);
+    }
+
+    public function testNotifyUserActivated(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $activatedUser = new User(); $this->setEntityId($activatedUser, 4);
+        $activatedUser->setName('Alice');
+        $activatedUser->setSurname('Wonder');
+
+        $org = new Organizations(); $this->setEntityId($org, 400);
+        $org->setName('Wonderland');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === 'user_activated'
+                    && $message->getTitle() === 'Membre réactivé'
+                    && str_contains($message->getMessage(), 'Alice Wonder a été réactivé dans Wonderland');
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyUserActivated($recipient, $activatedUser, $org);
+    }
+
+    public function testNotifyOrganizationUpdate(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $org = new Organizations(); $this->setEntityId($org, 500);
+        $org->setName('OrgUpdate');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_ORG_UPDATE
+                    && $message->getTitle() === 'Organisation mise à jour'
+                    && str_contains($message->getMessage(), 'L\'organisation OrgUpdate a été Renamed')
+                    && $message->getData()['action'] === 'Renamed';
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyOrganizationUpdate($recipient, $org, 'Renamed');
+    }
+
+    public function testNotifyAppAccessChangedGranted(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $org = new Organizations(); $this->setEntityId($org, 600);
+        $org->setName('AppCorp');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_APP_ACCESS
+                    && str_contains($message->getMessage(), 'L\'accès à Portal a été autorisé pour AppCorp')
+                    && $message->getData()['granted'] === true;
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyAppAccessChanged($recipient, $org, 'Portal', true);
+    }
+
+    public function testNotifyAppAccessChangedRevoked(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $org = new Organizations(); $this->setEntityId($org, 600);
+        $org->setName('AppCorp');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getData()['granted'] === false
+                    && str_contains($message->getMessage(), 'retiré');
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyAppAccessChanged($recipient, $org, 'Portal', false);
+    }
+
+    public function testNotifyRoleChanged(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $targetUser = new User(); $this->setEntityId($targetUser, 5);
+        $targetUser->setName('Tom');
+        $targetUser->setSurname('Role');
+
+        $org = new Organizations(); $this->setEntityId($org, 700);
+        $org->setName('RoleOrg');
+
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_ROLE_CHANGED
+                    && $message->getTitle() === 'Rôle modifié'
+                    && str_contains($message->getMessage(), 'Tom Role a été changé en ADMIN')
+                    && $message->getData()['newRole'] === 'ADMIN';
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyRoleChanged($recipient, $targetUser, $org, 'ADMIN');
+    }
+
+    public function testNotifyUserDeleted(): void
+    {
+        $recipient = new User(); $this->setEntityId($recipient, 1);
+        $deletedUser = new User(); $this->setEntityId($deletedUser, 99);
+        $deletedUser->setName('Del');
+        $deletedUser->setSurname('User');
+        $deletedUser->setEmail('del@test.com');
+
+        // Test without organization (null)
+        $this->messageBus->expects($this->once())
+            ->method('dispatch')
+            ->with($this->callback(function (NotificationMessage $message) {
+                return $message->getType() === NotificationService::TYPE_USER_REMOVED
+                    && $message->getTitle() === 'Utilisateur supprimé'
+                    && $message->getOrganizationId() === null
+                    && $message->getData()['userEmail'] === 'del@test.com';
+            }))
+            ->willReturn(new Envelope(new \stdClass()));
+
+        $this->service->notifyUserDeleted($recipient, $deletedUser, null);
+    }
+}
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