diff --git a/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverNotificationServiceTest.php b/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverNotificationServiceTest.php
new file mode 100644
index 0000000..3b837ec
--- /dev/null
+++ b/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverNotificationServiceTest.php
@@ -0,0 +1,153 @@
+<?php
+
+namespace MintyPHP\Tests\Module\Helpdesk\Service;
+
+use MintyPHP\Module\Helpdesk\Service\HandoverNotificationService;
+use MintyPHP\Service\Mail\MailService;
+use PHPUnit\Framework\TestCase;
+
+class HandoverNotificationServiceTest extends TestCase
+{
+    private function createNotificationService(?MailService $mailService = null): HandoverNotificationService
+    {
+        return new HandoverNotificationService(
+            $mailService ?? $this->createMock(MailService::class)
+        );
+    }
+
+    private function assignedHandover(array $overrides = []): array
+    {
+        return array_merge([
+            'id' => 1,
+            'debitor_name' => 'Acme Corp',
+            'domain_url' => 'example.com',
+            'due_date' => '2026-12-31',
+            'assigned_to_email' => 'employee@example.com',
+            'assigned_to_label' => 'John Doe',
+            'assigned_by_label' => 'Manager',
+            'assigned_by_email' => 'manager@example.com',
+        ], $overrides);
+    }
+
+    // ── notifyAssigned ────────────────────────────────────────────────
+
+    public function testNotifyAssignedSendsEmailToAssignee(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->once())
+            ->method('sendTemplate')
+            ->with(
+                'handover_assigned',
+                $this->callback(fn (array $vars): bool => $vars['assignee_name'] === 'John Doe'
+                    && $vars['assigned_by_name'] === 'Manager'
+                    && $vars['debitor_name'] === 'Acme Corp'
+                    && $vars['due_date'] === '2026-12-31'
+                ),
+                'employee@example.com',
+                $this->isType('string')
+            );
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyAssigned($this->assignedHandover());
+    }
+
+    public function testNotifyAssignedSkipsWhenNoEmail(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->never())->method('sendTemplate');
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyAssigned($this->assignedHandover(['assigned_to_email' => '']));
+    }
+
+    public function testNotifyAssignedSkipsWhenEmailIsNull(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->never())->method('sendTemplate');
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyAssigned($this->assignedHandover(['assigned_to_email' => null]));
+    }
+
+    public function testNotifyAssignedFallsBackToDashForEmptyDebitor(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->once())
+            ->method('sendTemplate')
+            ->with(
+                'handover_assigned',
+                $this->callback(fn (array $vars): bool => $vars['debitor_name'] === '—'),
+                $this->anything(),
+                $this->anything()
+            );
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyAssigned($this->assignedHandover(['debitor_name' => '']));
+    }
+
+    public function testNotifyAssignedFallsBackToDashForEmptyDueDate(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->once())
+            ->method('sendTemplate')
+            ->with(
+                'handover_assigned',
+                $this->callback(fn (array $vars): bool => $vars['due_date'] === '—'),
+                $this->anything(),
+                $this->anything()
+            );
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyAssigned($this->assignedHandover(['due_date' => '']));
+    }
+
+    // ── notifyReviewRequested ─────────────────────────────────────────
+
+    public function testNotifyReviewRequestedSendsEmailToManager(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->once())
+            ->method('sendTemplate')
+            ->with(
+                'handover_review_requested',
+                $this->callback(fn (array $vars): bool => $vars['manager_name'] === 'Manager'
+                    && $vars['assignee_name'] === 'John Doe'
+                    && $vars['debitor_name'] === 'Acme Corp'
+                ),
+                'manager@example.com',
+                $this->isType('string')
+            );
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyReviewRequested($this->assignedHandover([
+            'assigned_to_label' => 'John Doe',
+            'assigned_by_label' => 'Manager',
+            'assigned_by_email' => 'manager@example.com',
+        ]));
+    }
+
+    public function testNotifyReviewRequestedSkipsWhenNoManagerEmail(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->never())->method('sendTemplate');
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyReviewRequested($this->assignedHandover(['assigned_by_email' => '']));
+    }
+
+    public function testNotifyReviewRequestedFallsBackToDashForEmptyAssigneeName(): void
+    {
+        $mailService = $this->createMock(MailService::class);
+        $mailService->expects($this->once())
+            ->method('sendTemplate')
+            ->with(
+                'handover_review_requested',
+                $this->callback(fn (array $vars): bool => $vars['assignee_name'] === '—'),
+                $this->anything(),
+                $this->anything()
+            );
+
+        $service = $this->createNotificationService($mailService);
+        $service->notifyReviewRequested($this->assignedHandover(['assigned_to_label' => '']));
+    }
+}
diff --git a/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverServiceTest.php b/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverServiceTest.php
index e9aae39..c34f137 100644
--- a/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverServiceTest.php
+++ b/modules/helpdesk/tests/Module/Helpdesk/Service/HandoverServiceTest.php
@@ -3,6 +3,7 @@
 namespace MintyPHP\Tests\Module\Helpdesk\Service;
 
 use MintyPHP\Module\Helpdesk\Repository\HandoverRepository;
+use MintyPHP\Module\Helpdesk\Service\HandoverNotificationService;
 use MintyPHP\Module\Helpdesk\Service\HandoverRevisionService;
 use MintyPHP\Module\Helpdesk\Service\HandoverService;
 use MintyPHP\Module\Helpdesk\Service\SoftwareProductService;
@@ -19,11 +20,30 @@ class HandoverServiceTest extends TestCase
         ?HandoverRepository $repository = null,
         ?SoftwareProductService $productService = null,
         ?HandoverRevisionService $revisionService = null,
+        ?HandoverNotificationService $notificationService = null,
     ): HandoverService {
         $repository = $repository ?? $this->createMock(HandoverRepository::class);
         $productService = $productService ?? $this->createMock(SoftwareProductService::class);
 
-        return new HandoverService($repository, $productService, $revisionService);
+        return new HandoverService($repository, $productService, $revisionService, $notificationService);
+    }
+
+    private function handoverRow(array $overrides = []): array
+    {
+        return array_merge([
+            'id' => 1,
+            'tenant_id' => self::TENANT_ID,
+            'status' => HandoverService::STATUS_IN_PROGRESS,
+            'assigned_to' => 0,
+            'assigned_by' => 0,
+            'debitor_name' => 'Acme Corp',
+            'domain_url' => 'example.com',
+            'due_date' => null,
+            'assigned_to_label' => null,
+            'assigned_to_email' => null,
+            'assigned_by_label' => null,
+            'assigned_by_email' => null,
+        ], $overrides);
     }
 
     private function mockProductService(bool $exists = true, bool $hasSchema = true): SoftwareProductService
@@ -332,6 +352,288 @@ class HandoverServiceTest extends TestCase
         $service->createRevisionAfterSave(self::TENANT_ID, 1, ['name' => 'Test'], 'draft', false, false, 1, self::USER_ID);
     }
 
+    // ── Assign tests ─────────────────────────────────────────────────
+
+    public function testAssignHappyPath(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow(['status' => HandoverService::STATUS_IN_PROGRESS]));
+        $repo->expects($this->once())->method('assign')->willReturn(true);
+        $repo->expects($this->never())->method('updateStatus');
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, null, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertTrue($result['ok']);
+        $this->assertEmpty($result['errors']);
+    }
+
+    public function testAssignDraftHandoverTransitionsToInProgress(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow(['status' => HandoverService::STATUS_DRAFT]));
+        $repo->method('assign')->willReturn(true);
+        $repo->expects($this->once())
+            ->method('updateStatus')
+            ->with(self::TENANT_ID, 1, HandoverService::STATUS_IN_PROGRESS, self::USER_ID);
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, null, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertTrue($result['ok']);
+    }
+
+    public function testAssignDeniedForCreatePermission(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->expects($this->never())->method('assign');
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, null, HandoverService::PERMISSION_CREATE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('general', $result['errors']);
+    }
+
+    public function testAssignFailsWhenAssignedToIsZero(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow());
+        $repo->expects($this->never())->method('assign');
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 0, self::USER_ID, null, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('assigned_to', $result['errors']);
+    }
+
+    public function testAssignFailsWhenHandoverNotFound(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn(null);
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, null, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('general', $result['errors']);
+    }
+
+    public function testAssignSendsNotificationEmail(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to_email' => 'employee@example.com',
+            'assigned_to_label' => 'John Doe',
+        ]));
+        $repo->method('assign')->willReturn(true);
+
+        $notificationService = $this->createMock(HandoverNotificationService::class);
+        $notificationService->expects($this->once())->method('notifyAssigned');
+
+        $service = $this->createService($repo, notificationService: $notificationService);
+        $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, null, HandoverService::PERMISSION_MANAGE);
+    }
+
+    public function testAssignWithDueDatePassesItToRepository(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow());
+        $repo->expects($this->once())
+            ->method('assign')
+            ->with(self::TENANT_ID, 1, 99, self::USER_ID, '2026-12-31', self::USER_ID)
+            ->willReturn(true);
+
+        $service = $this->createService($repo);
+        $result = $service->assign(self::TENANT_ID, 1, 99, self::USER_ID, '2026-12-31', HandoverService::PERMISSION_MANAGE);
+
+        $this->assertTrue($result['ok']);
+    }
+
+    // ── Submit for review tests ───────────────────────────────────────
+
+    public function testSubmitForReviewHappyPathByAssignee(): void
+    {
+        $assigneeId = 99;
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => $assigneeId,
+            'status' => HandoverService::STATUS_IN_PROGRESS,
+        ]));
+        $repo->expects($this->once())
+            ->method('updateStatus')
+            ->with(self::TENANT_ID, 1, HandoverService::STATUS_UNDER_REVIEW, $assigneeId)
+            ->willReturn(true);
+
+        $service = $this->createService($repo);
+        $result = $service->submitForReview(self::TENANT_ID, 1, $assigneeId, HandoverService::PERMISSION_CREATE);
+
+        $this->assertTrue($result['ok']);
+    }
+
+    public function testSubmitForReviewAllowedForManager(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => 99,
+            'status' => HandoverService::STATUS_DRAFT,
+        ]));
+        $repo->method('updateStatus')->willReturn(true);
+
+        $service = $this->createService($repo);
+        $result = $service->submitForReview(self::TENANT_ID, 1, self::USER_ID, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertTrue($result['ok']);
+    }
+
+    public function testSubmitForReviewDeniedForNonAssignee(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => 99,
+            'status' => HandoverService::STATUS_IN_PROGRESS,
+        ]));
+
+        $service = $this->createService($repo);
+        $result = $service->submitForReview(self::TENANT_ID, 1, self::USER_ID, HandoverService::PERMISSION_CREATE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('general', $result['errors']);
+    }
+
+    public function testSubmitForReviewDeniedWhenStatusIsUnderReview(): void
+    {
+        $assigneeId = 99;
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => $assigneeId,
+            'status' => HandoverService::STATUS_UNDER_REVIEW,
+        ]));
+
+        $service = $this->createService($repo);
+        $result = $service->submitForReview(self::TENANT_ID, 1, $assigneeId, HandoverService::PERMISSION_CREATE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('status', $result['errors']);
+    }
+
+    public function testSubmitForReviewDeniedWhenStatusIsCompleted(): void
+    {
+        $assigneeId = 99;
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => $assigneeId,
+            'status' => HandoverService::STATUS_COMPLETED,
+        ]));
+
+        $service = $this->createService($repo);
+        $result = $service->submitForReview(self::TENANT_ID, 1, $assigneeId, HandoverService::PERMISSION_CREATE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('status', $result['errors']);
+    }
+
+    public function testSubmitForReviewSendsReviewRequestedEmail(): void
+    {
+        $assigneeId = 99;
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => $assigneeId,
+            'status' => HandoverService::STATUS_IN_PROGRESS,
+            'assigned_by_email' => 'manager@example.com',
+        ]));
+        $repo->method('updateStatus')->willReturn(true);
+
+        $notificationService = $this->createMock(HandoverNotificationService::class);
+        $notificationService->expects($this->once())->method('notifyReviewRequested');
+
+        $service = $this->createService($repo, notificationService: $notificationService);
+        $service->submitForReview(self::TENANT_ID, 1, $assigneeId, HandoverService::PERMISSION_CREATE);
+    }
+
+    public function testSubmitForReviewCreatesRevision(): void
+    {
+        $assigneeId = 99;
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow([
+            'assigned_to' => $assigneeId,
+            'status' => HandoverService::STATUS_IN_PROGRESS,
+        ]));
+        $repo->method('updateStatus')->willReturn(true);
+
+        $revisionService = $this->createMock(HandoverRevisionService::class);
+        $revisionService->expects($this->once())
+            ->method('createRevision')
+            ->with(
+                self::TENANT_ID,
+                1,
+                [],
+                HandoverService::STATUS_UNDER_REVIEW,
+                1,
+                $assigneeId,
+                HandoverRevisionService::CHANGE_TYPE_STATUS
+            );
+
+        $service = $this->createService($repo, revisionService: $revisionService);
+        $service->submitForReview(self::TENANT_ID, 1, $assigneeId, HandoverService::PERMISSION_CREATE);
+    }
+
+    // ── Resend notification tests ─────────────────────────────────────
+
+    public function testResendNotificationHappyPath(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow(['assigned_to' => 99]));
+
+        $notificationService = $this->createMock(HandoverNotificationService::class);
+        $notificationService->expects($this->once())->method('notifyAssigned');
+
+        $service = $this->createService($repo, notificationService: $notificationService);
+        $result = $service->resendNotification(self::TENANT_ID, 1, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertTrue($result['ok']);
+    }
+
+    public function testResendNotificationDeniedForCreatePermission(): void
+    {
+        $notificationService = $this->createMock(HandoverNotificationService::class);
+        $notificationService->expects($this->never())->method('notifyAssigned');
+
+        $service = $this->createService(notificationService: $notificationService);
+        $result = $service->resendNotification(self::TENANT_ID, 1, HandoverService::PERMISSION_CREATE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('general', $result['errors']);
+    }
+
+    public function testResendNotificationFailsWhenNoAssignee(): void
+    {
+        $repo = $this->createMock(HandoverRepository::class);
+        $repo->method('findById')->willReturn($this->handoverRow(['assigned_to' => 0]));
+
+        $notificationService = $this->createMock(HandoverNotificationService::class);
+        $notificationService->expects($this->never())->method('notifyAssigned');
+
+        $service = $this->createService($repo, notificationService: $notificationService);
+        $result = $service->resendNotification(self::TENANT_ID, 1, HandoverService::PERMISSION_MANAGE);
+
+        $this->assertFalse($result['ok']);
+        $this->assertArrayHasKey('general', $result['errors']);
+    }
+
+    // ── Status label / variant tests ─────────────────────────────────
+
+    public function testStatusLabelUnderReview(): void
+    {
+        $this->assertNotEmpty(HandoverService::statusLabel(HandoverService::STATUS_UNDER_REVIEW));
+    }
+
+    public function testStatusVariantUnderReview(): void
+    {
+        $this->assertSame('info', HandoverService::statusVariant(HandoverService::STATUS_UNDER_REVIEW));
+    }
+
     // ── Delete tests ─────────────────────────────────────────────────
 
     public function testDeleteByIdsHappyPath(): void