Hi Branden, > On the one hand I like the idea of detecting inadvertent changes to > vertical spacing (or anything else) in a document, but on the other, > I find narrowly scoped regression tests to be advantageous.
Agreed. I assume groff is a long way from a set of tests which give high code coverage. I think that swings in favour of detecting inadvertent changes. > I think maybe the best-of-both-worlds solution is to have a model > document-based automated test--perhaps one that exercises as many > ms(7) macros as possible. A bit of a torture test? Yes, worthy. > would add the highly sensitive Rumsfeldian "unknown unknowns" problem > detection that I think your suggestion is tuned to. I don't think it would catch the things not thought of, like the .bp within a display. I've probably mentioned it before, but a corpus of real-life documents would be good input to a troff test harness. Render each at, say, 150 pixels per inch in monochrome by default and compare against a golden version made earlier. Commands like ‘gm compare’ or gmic(1) can do the pixel comparison. A differing pixel would leave the diffs of each stage of the pipeline for eyeballing. So tbl's output is saved rather than just piped into troff. This needn't be part of groff's test suite, or anything to do with the FSF. It could be useful for comparing versions of other troffs. Documents could be tagged with what troffs they're compatible with and whether the test needs upgrading, say to colour pixels. A buildbot or similar could run the suite against a new release or Git commit. When a new document is thrown into the pot, a golden test result is eyeballed and saved. It's not too important whether it's perfect so it doesn't need costly proof-reading. What matters is a later change is detected and ensured to be deliberate. > > output=\ > > ',,,,,,The first page is 1.,, display,,,,,,,,, > > ,,, -2-,,,The second page is 2. > > ' > > output=$(echo "$output" | tr , \\012) > > This is a good suggestion for handling blank line-happy output, of > which we have quite a bit in groff. I of course produced it by doing the opposite, line feeds into commas, and then reverted a comma by hand where I wanted to show a page break with a linefeed. -- Cheers, Ralph.
