Over the course of the book we’ve talked about how important rapid feedback is to getting the full benefit of the TDD process.
You can make your TDD feedback happen faster in several ways. You can run a focused subset of your test suite so that you see only the tests relating to the code you’re working on. You can have tests run automatically when code changes. You can make the loading of the Rails application happen in the background or you can bypass Rails altogether. And, of course, you can just avoid doing really slow things.
Let’s look at the many ways to speed up tests.