How to use XCTest framework to test REST based native iOS appliction?

Tried to check out how to use XCTest framework for an application which is using REST web services. But did not find any good and complete example tutorial.

I have only some basic idea of XCTest but confused to use XCTest with REST application.

Can anybody give me some examples of how to use this. I just need the idea and direction and then I can go.

Note: If the application is a basic application, I know but my confusion is only for REST based iOS application testing.