Another simple example from my work of the moment: my goal is to import points from a file (that I'm assured does have points) using a 3rd party file import lib

Another simple example from my work of the moment: my goal is to import points from a file (that I'm assured does have points) using a 3rd party file import library. I don't know in advance how the 3rd party library imports points, so the best test I could possibly write ahead of time is a fairly high-level integration test, "Did we manage to import a point?" All my actual programming work here consists of adding printfs at strategic points to tease out exactly where I should be looking for the point data. Unit tests are completely useless for this process. Come to think of it, even once I've got it figured out, it's very hard to see how to usefully use unit tests here...