Why don’t people get it? I find it frustrating that some people still don’t see the need for it. You end up discovering things sooner rather than later, you build better quality code. Because when you find something wrong you fix it and hopefully write a test for it so it never happens again! You simply reduce the risk of change, which is so important in iterative development.
Anyway – enough of me ranting, here’s an excerpt from what looks like a good book on it, from the same series as Martin Folwer’s series on patterns continuous integration just makes sense