> I think people have learned to undervalue the properties of integration tests and overvalue the properties of unit tests. Is it nice to know exactly what's br

> I think people have learned to undervalue the properties of integration tests and overvalue the properties of unit tests. Is it nice to know exactly what's broken based on the test failure? Sure. Is it _as_ nice as having confidence that the whole system is working? Probably not, in a lot of cases. This comment alone demonstrates a collosal misunderstanding regarding unit tests. Unit tests are not used to verify if the system is working. They were never used for that. At all. Unit tests only specify invariants which are a necessary but insufficient to verify that the system works as expected. These invariants are used to verify that specific realizations of your input and state will lead your implementation to produce specific results, no matter which code you change. If you expect function foo to return true if you pass it a positive integer, you want to know if a code change suddenly leads it to return false or throw an exception. That's what unit tests are for. If unit tests worked anything remotely similar to the way you misrepresented them, we would not need integration or end-to-end tests at all, would we?