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Comment by what-no-tests | Hacker News Reader

If I'm writing unit tests for #some_method, I'll mock anything that method calls outside of that method (so I can check how that method will respond to error conditions from calling those other methods).

Unit tests != Integration tests, and the two must both exist otherwise I'll run into that situation where my unit tests work but the software doesn't.

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But do you not find the problem is you now end up with tests that assume the existence of #some_method with the tests tightly coupled to the internal logic and flow of that method?

If you decide to refactor, every part of the system now has one or more tests that break because they mimic or clone each method 1:1 rather than testing input and output.

Exactly the problem the 2nd guy had

Perhaps, but if I refactor #some_method I only have to look in my unit tests where I describe #some_method and focus there. The integration tests should not have to be updated, since they only describe expected behavior -- unless the expected behavior must change as well.

The coupling between unit tests and the methods they test is correct, IMO, because really how else are you supposed to test what #some_method would do when it tries to call #another_method but #another_method raises various different exceptions, or returns no results, or returns successfully? If the answer is "I only test happy paths" then good luck - you're not really testing anything.

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