public void GetDefault_Test() { // Arrange var mockService = new Mock <ILanguageService>(); mockService.Setup(x => x.GetDefault()) .Returns(new LanguageModel { IsDefault = true }); var controller = new LanguageController(mockService.Object); // Act IHttpActionResult actionResult = controller.GetDefault(); var contentResult = actionResult as OkNegotiatedContentResult <LanguageModel>; // Assert Assert.IsNotNull(contentResult); Assert.IsNotNull(contentResult.Content); Assert.IsTrue(contentResult.Content.IsDefault); }