public async void RemoveAllQuestions_ValidId_ReturnsOk() { // Arrange var mock = new Mock <ISurveyService>(); mock.Setup(s => s.RemoveAllQuestionsAsync(It.IsAny <int>())).Returns((int id) => FakeServicesMethods.DeleteQuestionFromSurvey(id)); var controller = new SurveyController(mock.Object); // Act var result = await controller.RemoveAllQuestions(1); var okResult = result as OkResult; // Assert Assert.NotNull(okResult); Assert.Equal(200, okResult.StatusCode); }