public async Task GetById_WhenCalled_UnknownID_ReturnsNotFoundResult() { var mockedRepo = new Mock <IHomeRepository>(); var sensors = new List <Sensor> { new Sensor() { Name = "test_sensor_1", Id = Guid.Parse("00000000-0000-0000-0000-000000000001") }, new Sensor() { Name = "test_sensor_2", Id = Guid.Parse("00000000-0000-0000-0000-000000000002") } }; mockedRepo.Setup(repo => repo.GetSensor(Guid.Parse("00000000-0000-0000-0000-000000000001"))).ReturnsAsync(sensors[0]); mockedRepo.Setup(repo => repo.GetSensor(Guid.Parse("00000000-0000-0000-0000-000000000002"))).ReturnsAsync(sensors[1]); var controller = new SensorsController(mockedRepo.Object, listenerClient, this.loggerMock); var result = await controller.Get("00000000-0000-0000-0000-000000000003"); var contentResult = result as NotFoundResult; Assert.NotNull(contentResult); }