[tuxie_]

Hi detaro. Good question. If all my module does is make an api call, and I mock the API, what am I testing? I would rather leave that out of the unit tests because the added value is, in my opinion, close to none if you are relying on mocked data.

Now, if the module does more than just call the API then I would argue that it's breaking the single responsibility principle and would prefer to split it into a module that does only the call and another that does the rest.

[detaro]

Ok, then go one level in: If a component uses the "only makes an API call module", how do I unit test it? I can't let it use the module to make the API call (because the API might not be available in testing/that's an integration test/...), and I can't mock it, because using a mock would make it a not-unit test? I guess this gets at the line between mocks and stubs, but I never found that all that convincing.

[tuxie_]

Yes, you just don't unit test it, because if you mock out the only dependency it has you are left with nothing. So you are not unit testing anything anyway. You know what I mean? That code can (and should) be tested, through an integration test.