The Importance of Test Driven Development

The community owes a great debt to Kent Beck and Ward Cunningham for test-driven development. There's an enormous difference in the quality of code when you have tests. If you've got a big wad of code out there, there's no tests, you're scared to death to touch it. You know you're going to break eight things in there. But if you have tests, you can reach into it and put a little of it and pull on it... It'll still pass. That didn't break anything, right? As long as the tests have enough coverage.