diff --git a/Tests/Controller/HeatmapControllerTest.php b/Tests/Controller/HeatmapControllerTest.php
index f340c24..0bf7051 100644
--- a/Tests/Controller/HeatmapControllerTest.php
+++ b/Tests/Controller/HeatmapControllerTest.php
@@ -11,6 +11,25 @@ use Symfony\Component\HttpFoundation\Request;
 
 class HeatmapControllerTest extends TestCase
 {
+    private function createControllerWithUser(): array
+    {
+        $user = $this->createMock(User::class);
+        $user->method('getTimezone')->willReturn('Europe/Berlin');
+        $user->method('getFirstDayOfWeek')->willReturn('monday');
+
+        $controller = new HeatmapController();
+        $container = $this->createMock(\Symfony\Component\DependencyInjection\ContainerInterface::class);
+        $tokenStorage = $this->createMock(\Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface::class);
+        $token = $this->createMock(\Symfony\Component\Security\Core\Authentication\Token\TokenInterface::class);
+        $token->method('getUser')->willReturn($user);
+        $tokenStorage->method('getToken')->willReturn($token);
+        $container->method('has')->willReturn(true);
+        $container->method('get')->willReturn($tokenStorage);
+        $controller->setContainer($container);
+
+        return [$controller, $user];
+    }
+
     public function testDataReturnsJsonWithDaysAndRange(): void
     {
         $mockDays = [
@@ -20,18 +39,7 @@ class HeatmapControllerTest extends TestCase
         $service = $this->createMock(HeatmapService::class);
         $service->method('getDailyAggregation')->willReturn($mockDays);
 
-        $controller = new HeatmapController();
-
-        // Mock user via reflection (AbstractController::getUser is protected)
-        $user = $this->createMock(User::class);
-        $container = $this->createMock(\Symfony\Component\DependencyInjection\ContainerInterface::class);
-        $tokenStorage = $this->createMock(\Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface::class);
-        $token = $this->createMock(\Symfony\Component\Security\Core\Authentication\Token\TokenInterface::class);
-        $token->method('getUser')->willReturn($user);
-        $tokenStorage->method('getToken')->willReturn($token);
-        $container->method('has')->willReturn(true);
-        $container->method('get')->willReturn($tokenStorage);
-        $controller->setContainer($container);
+        [$controller, $user] = $this->createControllerWithUser();
 
         $response = $controller->data(new Request(), $service);
 
@@ -43,4 +51,143 @@ class HeatmapControllerTest extends TestCase
         $this->assertArrayHasKey('begin', $data['range']);
         $this->assertArrayHasKey('end', $data['range']);
     }
+
+    public function testDataReturnsHourlyMode(): void
+    {
+        $mockHours = [['hour' => 9, 'hours' => 2.0, 'count' => 5]];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getHourlyAggregation')->willReturn($mockHours);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $request = new Request(['mode' => 'hourly']);
+        $response = $controller->data($request, $service);
+
+        $data = json_decode($response->getContent(), true);
+        $this->assertArrayHasKey('hours', $data);
+        $this->assertArrayHasKey('range', $data);
+        $this->assertEquals($mockHours, $data['hours']);
+    }
+
+    public function testDataReturnsDayHourMode(): void
+    {
+        $mockMatrix = [['day' => 0, 'hour' => 9, 'hours' => 1.0, 'count' => 1]];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getDayHourAggregation')->willReturn($mockMatrix);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $request = new Request(['mode' => 'dayhour']);
+        $response = $controller->data($request, $service);
+
+        $data = json_decode($response->getContent(), true);
+        $this->assertArrayHasKey('matrix', $data);
+        $this->assertArrayHasKey('range', $data);
+        $this->assertEquals($mockMatrix, $data['matrix']);
+    }
+
+    public function testDataDefaultsToDailyMode(): void
+    {
+        $mockDays = [['date' => '2026-01-01', 'hours' => 1.0, 'count' => 2]];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getDailyAggregation')->willReturn($mockDays);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $request = new Request(); // no mode param
+        $response = $controller->data($request, $service);
+
+        $data = json_decode($response->getContent(), true);
+        $this->assertArrayHasKey('days', $data);
+        $this->assertEquals($mockDays, $data['days']);
+    }
+
+    public function testDataPassesFilterParams(): void
+    {
+        $service = $this->createMock(HeatmapService::class);
+        $service->expects($this->once())
+            ->method('getDailyAggregation')
+            ->with(
+                $this->anything(),  // user
+                $this->anything(),  // begin
+                $this->anything(),  // end
+                $this->isNull(),    // projectId
+                3,                  // customerId
+                5                   // activityId
+            )
+            ->willReturn([]);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $request = new Request(['activity' => '5', 'customer' => '3']);
+        $controller->data($request, $service);
+    }
+
+    public function testCustomersEndpoint(): void
+    {
+        $mockCustomers = [['id' => 1, 'name' => 'Acme']];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getUserCustomers')->willReturn($mockCustomers);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $response = $controller->customers($service);
+
+        $this->assertInstanceOf(JsonResponse::class, $response);
+        $data = json_decode($response->getContent(), true);
+        $this->assertEquals($mockCustomers, $data);
+    }
+
+    public function testProjectsEndpoint(): void
+    {
+        $mockProjects = [['id' => 1, 'name' => 'Web']];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getUserProjects')->willReturn($mockProjects);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $response = $controller->projects(new Request(), $service);
+
+        $this->assertInstanceOf(JsonResponse::class, $response);
+        $data = json_decode($response->getContent(), true);
+        $this->assertEquals($mockProjects, $data);
+    }
+
+    public function testActivitiesEndpoint(): void
+    {
+        $mockActivities = [['id' => 1, 'name' => 'Dev']];
+
+        $service = $this->createMock(HeatmapService::class);
+        $service->method('getUserActivities')->willReturn($mockActivities);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $response = $controller->activities(new Request(), $service);
+
+        $this->assertInstanceOf(JsonResponse::class, $response);
+        $data = json_decode($response->getContent(), true);
+        $this->assertEquals($mockActivities, $data);
+    }
+
+    public function testActivitiesWithProjectParam(): void
+    {
+        $service = $this->createMock(HeatmapService::class);
+        $service->expects($this->once())
+            ->method('getUserActivities')
+            ->with(
+                $this->anything(),  // user
+                3                   // projectId
+            )
+            ->willReturn([]);
+
+        [$controller, $user] = $this->createControllerWithUser();
+
+        $request = new Request(['project' => '3']);
+        $controller->activities($request, $service);
+    }
 }