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But mocks are a model of the dependency. I don't quite see how a fake is a better model than a mock.

In any case, I agree testing close to a real system, with actual dependencies where possible is better. But that's not done with a fake.

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The kind of mocks the OP is arguing against are not really a model of the dependency, they're just a model of a particular execution sequence in the test, because the mock is just following a script. Nothing in it ensures that the sequence is even consistent with any given understanding of how the dependency works, and it will almost certainly need updating when the code under test is refactored.

My point is that a fake doesn't magically fix this issue. Both are narrow models of the underlying interface. I don't still quite understand why a mock is worse than a fake, when it comes to narrow models of the interface. If there is a method that needs to be called with a specific set up, there is no practical difference between a fake and a mock.

Again, none of this is a replacement for writing integration tests where possible. Mocks have a place in the testing realm and they are not an inherently bad tool.

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