> Frankly good type systems displaced TDD for me. They do a better job getting at the goals of TDD than TDD does. I think it's a false dichotomy. Where you hav

> Frankly good type systems displaced TDD for me. They do a better job getting at the goals of TDD than TDD does. I think it's a false dichotomy. Where you have types, use types. Where you don't, use tests. Either way, get a tool to guide you to the answer and then check the invariant during future changes. In fact TDD made me more aware of and appreciative of types. Writing types-by-hand is very tedious and wasteful.