public void AddCarFunction() { // Arrange: var okCar = _data.okCar; CarViewModel invalidCar = null; // Act: var okResponse = _carController.AddCarFunction(okCar); CreatedAtActionResult okResult = okResponse as CreatedAtActionResult; var badResponse = _carController.AddCarFunction(invalidCar); BadRequestResult badResult = badResponse as BadRequestResult; var invalidModelStateResponse = _carController.AddCarFunction(invalidCar); StatusCodeResult badStatus = invalidModelStateResponse as StatusCodeResult; // Assert: Assert.IsInstanceOfType(okResponse, typeof(CreatedAtActionResult)); Assert.IsInstanceOfType(badResponse, typeof(BadRequestResult)); Assert.IsInstanceOfType(badResponse, typeof(StatusCodeResult)); }