I don't think my point was extreme at all. The example I posted was an extremely typical, even tame example of dependency injection and architecture for the ben

I don't think my point was extreme at all. The example I posted was an extremely typical, even tame example of dependency injection and architecture for the benefit of testability. I've seen countless variations of pretty much exactly that or something quite similar (pulling out explicit dependencies to be injected that should never reasonably change in normal circumstances). Regarding "should we only exercise them from the UI level" - I'm not 100% sure what you're getting at - but if your point is that we should focus our testing on business-facing use cases and not trivialities of what class calls what method, then we're speaking past each other and are in complete agreement.