Android Programming: The Big Nerd Ranch Guide, 4th Edition

For the More Curious: Mocks and Testing

Mocking has a much different role in integration testing than it does in unit testing. Mock objects exist to isolate the component under test by pretending to be other, unrelated components. Unit testing tests an individual class; each class will have its own distinct dependencies, so each test class has a different set of mock objects. Since the mock objects are different in each test class, and the behavior rarely matters, mock frameworks that make it easy to create simple mock objects (like Mockito) are a great fit for unit tests.

Integration tests, on the other hand, are meant to test a larger piece of the app as a whole. Instead of isolating pieces of the app from each other, you use mocks ...