Unit testing isn't a bad idea, but it's not an incredibly prolific one either. Maybe I haven't gotten the proper intro to testing, but what I've seen (mainly in rails blog articles) is a joke. If I'm going to test a function I want to test the entire domain of inputs -- assertEquals(square(2) , 4) is totally useless.

I'd be happy to have someone show me an example of a useful rails-related test.