public void GetFizzBuzzText_ReturnsFizzBuzzTextGeneratedFromService() { //Arrange //"Mock the service so that it always returns some (randomly generated) string" var expectedText = Guid.NewGuid().ToString(); _serviceMock.Setup(s => s.GenerateFizzBuzzText(It.IsAny <int>(), It.IsAny <int>(), It.IsAny <int>())).Returns(expectedText); //Act var result = _controller.GetFizzBuzzText(It.IsAny <int>(), It.IsAny <int>(), It.IsAny <int>()) as OkNegotiatedContentResult <string>; //Assert //TODO: assert that the correct IHttpActionResult is returned //TODO: assert that the FizzBuzzService was used correctly Assert.That(result, Is.Not.Null); Assert.That(result.Content, Is.EqualTo(expectedText)); _serviceMock.Verify(s => s.GenerateFizzBuzzText(It.IsAny <int>(), It.IsAny <int>(), It.IsAny <int>()), Times.Once); }