following is my understanding...
if you create test objects locally and feed your local service with that, you are using mock object. this will give a test for the method you implemented in your local service.it is used to verify behaviors
when you get the test data from the real service provider, though from a test version of interface and get a test version of the object, you are working with stubsthe stub can have logic to accept certain input and give corresponding output to help you perform state verification...