But if you believe in your manual heuristics enough to ship them, you must already have a body of tests that you're happy with, right? Also seems like this is

But if you believe in your manual heuristics enough to ship them, you must already have a body of tests that you're happy with, right? Also seems like this is a case where generating synthetic data would be a big help. You don't have to use only real-world documents for training, just examples of the sorts of things real-world documents have in them. Make a vast corpus of semi-random documents in semi-random fonts and settings, printed from Word, Pandoc, LaTeX, etc.