I had tried out the canonical rspec framework for testing my Rails applications, but it didn't really fit in with the way I like work. I'm trying out test/spec now, and it looks pretty neat, it fits in really nicely with test/unit, so it allows you to do TDD and BDD at the same time. I think BDD is cool, but I want to be able to do TDD when it makes sense to do it.
A lot of BDD, a little TDD.
(BDD = Behaviour Driven Development)
(TDD = Test Driven Development)
