[speedkills]

I can feel him searching for the difference, and think he is so close but I have a slightly different take on it. He says over time you become confident enough in something that you don’t bother mocking it. Others have said they don’t bother mocking primitives. I would say you don’t bother mocking values. Objects with mutation, methods that cause side effects, these things need to be mocked, pure values never do. The system clock has been around a long time, and I trust it, but it has mutation, so I will mock it. If I make a new point class that is just an immutable wrapper for two immutable integers I won’t mock it. Pure functions never need to be mocked. Immutable values never need to be mocked. These don’t need time to become trusted, they are created trustworthy.