Basically what Cyph0n said, fakes and mocks aren't the same thing. But it isn't quite as smelly when I see a mock (or "stub" more typically) used as an expedie

Basically what Cyph0n said, fakes and mocks aren't the same thing. But it isn't quite as smelly when I see a mock (or "stub" more typically) used as an expedient way to create a fake to pass in as a dependency. Like you said, it is asserting on the interactions with a mock that is what primarily smells bad to me. I very rarely (honestly I think maybe never) see this done in a way that isn't just rewriting the implementation of the method as expectations in the test.