> Mocking is one tool used for writing tests that do not vary with unrelated implementations What if I chose the wrong abstractions (coupling things that shoul

> Mocking is one tool used for writing tests that do not vary with unrelated implementations What if I chose the wrong abstractions (coupling things that shouldn't be coupled and splitting things in the wrong places) and have to refactor the implementation to use different interfaces and different parts? All the tests will be testing the old parts using the old interfaces and will all break.