Question

I’ve been using Moq framework in c# for mocking in unit tests however there is one thing I dont complete understand yet. I have this line of code

var feedParserMock = new Mock<ApplicationServices.IFeedParser>();
feedParserMock.Setup(y => y.ParseFeed(csv)).Returns(items).Verifiable();

The second line does it mean it will only return the value if the parameter passed is the same? because the parameter that I pass to ParseFeed inside my controller is build inside the controller and I dont have access to it in the unit test. Currently the method is returning null, is there any way to specify I want to return my items variable no matter what the parameter is?

Answer 1

Yes. Moq provides the It static class that has helper methods for specifying parameters that satisfy certain criteria. Your example could be:

feedParserMock.Setup(y => y.ParseFeed(It.IsAny<string>())).Returns(items).Verifiable();

Then Moq will match your setup, given that the parameter is of the specified type and non-null (I chose string here, you should of course replace that with the correct type of your parameter in order for the code to compile).

You can also pass a delegate that Moq will evalute in order to determine if the setup is a match. Example:

feedParserMock.Setup(y => y.ParseFeed(It.Is<string>(s => s.Length > 3));

This will match any method invocations on ParseFeed, where the parameter is a string with a Length larger than 3.

Check out the “Matching arguments” section of the Moq Quickstart guide to learn more.