public void AddShouldAddNewLinkToDbAndReturnShortUrl() { // Arrange var linkService = A.Fake <IDataLinkService>(); A.CallTo(() => linkService.Add(A <Link> .Ignored)) .ReturnsLazily((Link link) => link); var linkBuilder = A.Fake <IShortLinkBuilder>(); A.CallTo(() => linkBuilder.Build(A <ActionContext> .Ignored, A <long> .Ignored)) .ReturnsLazily((ActionContext context, long id) => $"coded short url"); var controller = new LinkController(linkService, linkBuilder, CreateTokenServiceMock()); // Act var result = controller.Add("some url").Value as AddViewModel; // Assert Assert.That(result.ShortUrl, Is.EqualTo("coded short url")); }