public void FormsCreateFormUrlFormedCorrectly() { var mockDataSource = MockRepository.GenerateMock <IWebClient>(); var expectedUrl = Constants.CreateFormUrl; // Arrange mockDataSource .Stub(x => x.UploadString( Arg <string> .Is.Anything, // uri Arg <string> .Is.Anything, // method Arg <string> .Is.Anything, // content-type Arg <string> .Is.Anything // data )) .Return(string.Empty); // Act var target = new Forms(apiKey: Constants.ApiKey) { UserWebClient = mockDataSource }; target.CreateForm(""); // Assert mockDataSource.AssertWasCalled(c => c.UploadString( uri: Arg <string> .Matches(actualUrl => actualUrl == expectedUrl), method: Arg <string> .Is.Anything, contentType: Arg <string> .Is.Anything, data: Arg <string> .Is.Anything)); }