Yum! I love Ruby vs Smalltalk flame wars. This one is about whether TDD renders debuggers useless. Giles Bowkett of Ruby vs James Robertson of Smalltalk. I would have to talk James' side here. Although great TDD/BDD can remove the need for the debugger, it's not easy to do great TDD/BDD. It's an art, and takes a good amount of commitment and effort to do, as well as training(I am sure I still don't know the best ways to test in some situations). Basically, TDD is something you have to go out of your way in order to do well, and to say that everyone should do great TDD is a bit like forcing a religion down someone's throat. I think I do OK TDD/BDD. I don't use the debugger on Ruby projects, but would I use it if there were a good one? Yes.