Feature/honest mocks

[horkhe]

Meck is so powerful that it allows mocking non-existent functions and even non-existent modules. But as every coin it comes with two sides. And the bad thing here is that all sorts of problem caused by refactoring/removing/renaming actions are not detected by meck featured unit tests. Namely:

• a mocked module was removed/renamed;
• an expected function was removed/renamed;
• arguments were removed/added to an expected function;

To have such cases detected at the earliest possibility honest mocks were introduced. They expose the following properties:

• they are created with honest option;
• an attempt to create a mock by meck:new(mod, [honest]) for a module that does not exist fails with undefined_module error;
• an attempt to expect a function that is not exported from the honestly mocked module fails with cannot_mock_fake error.

I personally think that all mocks created by meck should be honest by default, but I did not want to break the backwards compatibility.

[eproxus]

I also like the idea of using honest by default. My guess is that 95-99 percent of the mocking done with Meck is with preexisting modules. Perhaps (if we make it default) another option could be added to make them "non-honest"? Like meck:new(mod, [unknown])?

[horkhe]

@eproxus so I will make mocks "honest" by default, and introduce an option to allow mocking of non-existing functions/modules. Though I find "unknown" a little bit confusing. What about "non_strict"?

[eproxus]

non_strict is much better.

[eproxus]

I find cannot_mock_fake a bit vague. Cannot come up with anything better, ideas I had were only_existing_functions_allowed, strict_mode, function_not_in_original or only_original_functions. They're all a bit long though. Perhaps undefined_function to go with undefined_module?

[horkhe]

Yep, undefined_function is good.

[horkhe]

@eproxus I made mocks honest by default and changed the exception for the undefined function case as we discussed.

[horkhe]

@eproxus have you had a chance to take a look at the changes?

[horkhe]

@eproxus hey man, how are you? I hope you did not fall off the planet :-)

[eproxus]

@horkhe Haha, no. I just moved to Germany so I've been a bit busy. :-) I'll do a last sweep and then we'll merge.

[eproxus]

To better match undefined_function, make this undefined_module instead.

[horkhe]

@eproxus Moved to Germany, that is cool. I suppose that was caused by a generous job offer, so my congratulations!

Back to business. The code is rebased and adjusted.

[eproxus]

@horkhe You, sir, are correct. :-)

[horkhe]

@eproxus I am genuinely curious if you new job is Erlang related?

[eproxus]

Yes, it is. I've started working at Wooga in Berlin. If you want a referral, let me know. :-)

[horkhe]

Thanks a lot for the suggestion! :-)