Using TDD everywhere is stupid. I think, tests are most useful between layers of abstraction, especially if you are the provider of abstraction. If you are mere

Using TDD everywhere is stupid. I think, tests are most useful between layers of abstraction, especially if you are the provider of abstraction. If you are merely a user of abstraction, it is stupid to unit test that code. If you have an interface to the outside, then that should be unit tested.