Floris, that's exactly the answer I was most afraid of. oh no. Zach, great minds! any thoughts on what i've done so far in my plugin, things i've missed, things i could add? https://github.com/hjwp/pytest-icdiff
On Thu, 9 Apr 2020 at 04:48, Zach Kanzler <they4k...@gmail.com> wrote: > I wrote an icdiff-based pretty diffs pytest plugin for internal use, and > ran into the same issue. I ended up grabbing the terminal width at > module-level, as well. I think I went spelunking in the GH issues and found > a glimmer of possibility in the notion that get_terminal_width() returns > incorrect information from within the assertrepr hook, because it's > called when terminal capturing is enabled — perhaps even just a wrapped > stream? > > Here's the note I left myself: > > # This is done during initialization, before any tests are run, instead of > # within our assertrepr hook — because the assertrepr hook is called while > # terminal capturing is enabled and all calls to get_terminal_width() > return 80 > # ref: > https://github.com/pytest-dev/pytest/issues/4030#issuecomment-425672782 > INITIAL_TERM_WIDTH, INITIAL_TERM_HEIGHT = util.get_terminal_size() > > > (Where util.get_terminal_size() just comes from this gist > <https://gist.github.com/jtriley/1108174>) > > I wonder if a tool like screen or tmux could supply real sizing info and > resize events, while also appearing like an unwrapped stream — and perhaps > its output could be saved & compared against. > > Cheers, > Zach > > On Wed, Apr 8, 2020 at 4:55 PM Floris Bruynooghe <f...@devork.be> wrote: > >> Hi Harry, >> >> To the best of my knowledge you stumbled into a hard and dark corner of >> pytest. IIRC previous attempts at improving this have not gone too >> well. But like this always goes, it sounds like you've set yourself up >> to be the expert now and are in a great position to clean this up and >> make it work nicely for people. ;) >> >> Cheers, >> Floris >> >> On Tue 07 Apr 2020 at 19:26 +0100, Harry Percival wrote: >> >> > cf discussion here https://github.com/pytest-dev/pytest/issues/162 >> > >> > I'm working on pytest-icdiff, trying to get it to print out well >> optimised >> > messages for different terminal sizes, and it's hard. >> > >> > when i'm running tests using runpytest, and I _think_ in real life too, >> > config.get_terminal_writer().fullwidth *inside the hook* is returning >> > incorrect values: resizing the terminal i'm using to run the tests has >> no >> > effect on the value i get from it. and when I use that value irl, real >> > test output does not adjust correctly to the terminal size >> > >> > but calling py.io.TerminalWriter().fullwidth _outside_ the hook, eg at >> > module level, _does_ give me readings that look right. but testing >> that >> > is hard. >> > >> > intriguingly, if I do testdir.monkeypatch.setenv('COLUMNS', '50'), then >> the >> > fullwdith *inside* the hook varies. but that's no use to me, since IRL >> > that value doesn't work. >> > >> > so my question is: a) does anyone know of any good examples of >> assertrepr >> > plugins that adjust dynamically to terminal width, and b) what's a good >> way >> > of writing tests for that? >> > >> > here's the repo fwiw >> > >> https://github.com/hjwp/pytest-icdiff/blob/master/tests/test_pytest_icdiff.py >> > _______________________________________________ >> > pytest-dev mailing list >> > pytest-dev@python.org >> > https://mail.python.org/mailman/listinfo/pytest-dev >> _______________________________________________ >> pytest-dev mailing list >> pytest-dev@python.org >> https://mail.python.org/mailman/listinfo/pytest-dev >> >
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