public void GetItemTest(bool isExists) { var rootTask = new Task { Id = TaskId }; if (isExists) { _tasksRepositoryMock.Setup(tasksRepository => tasksRepository.Get(TaskId)).Returns(rootTask); _tasksRepositoryMock.Setup(tasksRepository => tasksRepository.GetAll()).Returns(Enumerable.Empty <Task>()); // TODO: Setup mapper Mock } else { _tasksRepositoryMock.Setup(tasksRepository => tasksRepository.Get(TaskId)).Returns((Task)null); } var actualTask = _tasksService.GetItem(TaskId); _tasksRepositoryMock.Verify(tasksRepository => tasksRepository.Get(TaskId), Times.Once); if (isExists) { _tasksRepositoryMock.Verify(tasksRepository => tasksRepository.GetAll(), Times.Once); Assert.AreEqual(TaskId, actualTask.Id); } else { Assert.AreEqual(null, actualTask); } }