Surprising his tweet blew up, one of the goals of tests (TDD) is to validate your software still works after refactoring. This is a key element of being able t

Surprising his tweet blew up, one of the goals of tests (TDD) is to validate your software still works after refactoring. This is a key element of being able to change your code quickly and with confidence. Meaning if you couple your tests to the structure of your code, then it's not going to be quick when you restructure.