Comment by jonahkagan

That's a great point. I definitely agree that erring on the side of modules is better. I just worry about times when the purpose of a module is not clearly defined at the outset (e.g. when it only contains one function that is only used in one other module). I have often seen that devolve into the "helper" module, where random functions collect.

I'm also not sure I buy the assertion that all code you would want to test is code you would want to export publicly. Do you have any reasoning to support that idea?