NOT having tests is dept. When you can’t fearlessly add features quickly because you introduce regressions in another end of the product that you didn’t think o

NOT having tests is dept. When you can’t fearlessly add features quickly because you introduce regressions in another end of the product that you didn’t think of, and later have to spend all your time on firefighting because it got deployed to prod. If your mocks and tests are in the way when introducing features or refactoring, they are likely not on the right level. Too much unit testing of moving internals, rather than public apis, usually being one of the culprits.