One reason to use a tool like this is to supplement hand-written unit tests when doing a refactor. Ultimately, a lot of unit tests' jobs are just to catch unexp

One reason to use a tool like this is to supplement hand-written unit tests when doing a refactor. Ultimately, a lot of unit tests' jobs are just to catch unexpected side-effects of a code change. > tests should be written from requirements TDD might be too big of a debate to fit in an HN comment thread :)