s Best Practice Actually Poor Practice? Dependency Injection, Type Hinting, and Unit Tests...
I've recently been in discussion with a colleague who thinks that dependency injection (DI) is over-used and, in cases where the dependency is a concrete class, unnecessary (in the latter case, he advocates simply creating new objects on the fly). I raised the point that dependency injection allows you to pass in a mock object while unit testing, but he dismissed that as irrelevant and not a valid argument as to why dependency injection is useful.