Described as such in book-rails-4-test-prescriptions
"I'll also point out that as far as I'm concerned, the only... and I mean only reason I use mocks is to guide design during TDD. If I'm not writing tests first, there is very little point writing mocks. I believe I am consistent with the authors of GOOS (and inventors/popularizers of mocking) in this view." - Avdi Grimm somewhere on parley, I believe.