I typically find it very difficult to understand complex functions, (100+ lines of code, ~3 or more nesting levels deep) and even simpler complex functions (mixing 2-3 concepts into a 15 line function).
I've only just started doing TDD the "Growing Object Oriented Software guided by tests" way, and I find it incredibly helpful that each and every class does just _one_ thing, even splitting up those 15 line functions into two or three separate classes implementing an interface -- single responsibility -- helps me a lot in reasoning about the code.
I _have_ experienced the dependencies issue myself already though, it's very annoying to click on a method in my IDE, and then get shown the interface definition of that particular method. I'll then have to trace my way through a couple of files to find the dependency, very annoying.
I've only just started doing TDD the "Growing Object Oriented Software guided by tests" way, and I find it incredibly helpful that each and every class does just _one_ thing, even splitting up those 15 line functions into two or three separate classes implementing an interface -- single responsibility -- helps me a lot in reasoning about the code.
I _have_ experienced the dependencies issue myself already though, it's very annoying to click on a method in my IDE, and then get shown the interface definition of that particular method. I'll then have to trace my way through a couple of files to find the dependency, very annoying.