Absolutely. John Hughes with other smart guys even invented property-check tests for that. Andrea brough it to elixir world with stream_data. Validating the one outcome for the one income would not do that, though.
That’s a false dichotomy. I am not advocating for running a spaghetti monster. I am saying that if you need/want to test the function for the outcome, this function always deserves to be a part of some behaviour. That way you keep your code organized, contrary to a bunch of isolated functions, stuck to their impls.
