Look at your Rails unit test suite. Now look at mine. Now look at yours again. Mine are sub-second. Yours aren't. Having a slow unit test suite can hinder an effective test-first or test-driven approach to development. As you add tests, the suite starts to slow down to the point where you stop running them after each change. Some people even talk about multi-minute unit tests suites! Band-aids like spork are just covering up the problem. Test-driven development is a major player in keeping your design malleable and accepting of new features, but when you stop paying attention to the messages your tests are sending you, you lose this benefit.
In this talk, I will go over some techniques for keeping your test suite lean and fast. Along the way, we'll discuss the design improvements that come out of these changes.
Now, look at my unit test suite again. Yours can be like mine.