public void About() { // Arrange _mockService.Setup(x => x.GetMessage(It.IsAny<int>())).Returns("This works, too!"); var controller = new HomeController(_mockService.Object); // Act var result = controller.About() as ViewResult; // Assert _mockService.Verify(x => x.GetMessage(It.IsAny<int>()), Times.Once()); Assert.IsNotNull(result); Assert.AreEqual("This works, too!", result.ViewBag.Message); }