I practice TDD for the most part, I agree that it's not easy. E.g. there are a lot of unanswered questions: What if you write the test first, red, write the cod

I practice TDD for the most part, I agree that it's not easy. E.g. there are a lot of unanswered questions: What if you write the test first, red, write the code but it's still red. Could be your code wrong, could be your test wrong. If your test is wrong, do you go back and see the red? (I do). Do you test your tests? (I don't). Treating TDD like a formal system doesn't make any sense since it's meant to be a tool engineer can use as a heuristic to make judgements about the stage of the development.