The theory for test-first is you'll come up with a more testable design, and have better, cleaner, more focused tests if you write them first, then design the c

The theory for test-first is you'll come up with a more testable design, and have better, cleaner, more focused tests if you write them first, then design the code based on the tests. If you write the code first, then try to write the tests after, you may have to refactor code to support testing (if you're not used to writing testable code), or you might end up having to do very convoluted tests to make them work (see above re: 3-level mocks), or you might just accept subpar test coverage