>The most important tests, though, for refactoring are tests that you throw away. We’re hesitant. We love deleting code, but we hate deleting tests, because it gives us this feeling of insecurity. The sort of test that you do during refactoring doesn’t lend itself well to maintaining code over time. You’re going to be a lot more granular in your tests. You’re going to be testing things that are outside of the purview of normal integration or unit tests, and it’s important that you feel comfortable throwing those away when you’re done with a refactoring effort.

If you're throwing away a lot of your tests, that's generally a sign that your tests and your code are too tightly coupled.