Oh, I don't think isolating logic necessarily adds a layer, unless you go overboard with isolating it. I think we're probably caught up on the subtle difference

Oh, I don't think isolating logic necessarily adds a layer, unless you go overboard with isolating it. I think we're probably caught up on the subtle differences between encapsulation and abstraction. There seems to be a point where "I can't figure out what's happening here without an IDE" starts to happen, which is a) relatively subjective and b) sometimes a necessary side-effect. I only care when it's hard to test something in isolation when it's actually used in isolation. A private method, for example, exists only to be used by another component; it often makes little sense to test independently, and when it does it's easy to wrap in a public call that asserts that it's being run by a unit test. But I think a lot of this is theoretical code purity vs prioritizing business goals. All else being equal I'd love a perfectly-factored codebase, but at the end of the day I have to target high-friction, high-confusion areas of the codebase to refactor because those are the ones that get in the way of building stuff for our customers, or cause the most production bugs.