Personally I am loath to add extra functionality to the real system just to make testing easier. I am massively in favor of keeping the complexity in the real s

Personally I am loath to add extra functionality to the real system just to make testing easier. I am massively in favor of keeping the complexity in the real system down. Adding more hooks, or increasing the interface of the real system, just to make it more testable feels wrong. This is why I'd want test to just have a lot more 'leeway' than normal code. Essentially I want heavy hooking, introspection and reflexivity but only for tests.