public void CreateTest_BW() { //arrange var mockRepo = new Mock <IBookService>(); var controller = new BooksController(mockRepo.Object); var newValidItem = new Book() { Author = "Author", Title = "Title", Description = "Description" }; //act var result = controller.Create_BW(newValidItem); //assert var redirectToActionResult = Assert.IsType <RedirectToActionResult>(result); Assert.Equal("Index", redirectToActionResult.ActionName); Assert.Null(redirectToActionResult.ControllerName); //arrange var newInvalidItem = new Book() { Title = "Title", Description = "Description" }; controller.ModelState.AddModelError("Author", "The Author value is required"); //act var resultInvalid = controller.Create_BW(newInvalidItem); //assert var badRequestResult = Assert.IsType <BadRequestObjectResult>(resultInvalid); Assert.IsType <SerializableError>(badRequestResult.Value); }