When I discuss TDD with a new co-worker I first try to classify his/her approach to TDD. I do the same when I start working on a new codebase. I look at the codebase and try to find out if the codebase was written with a mockist or classicist TDD approach.

For me, the main difference is that classicist testers try to write the test so that they do not break when you change the implementation (e.g refactoring). Mockist don’t care so much about this, they focus on isolating the unit.

Whatever style is used, I try to be consistent with the codebase even though I prefer the classicist style. I’m convinced that isolating the code under test causes more problem than it solv