The `test_html_regression_875281` in `tests/test_presenters.py` takes more than 1min, about 70% of the time to run the entire test suite (357 passed, 78 skipped) on my system. In other words, excluding this single test makes testing almost 3 times faster on my system with one process. With `pytest-3 --numprocesses=4`, excluding this single test makes running the whole suite between 5 and 6 times faster. This of course also consumes 3 times more valuable CI resources and delays the CI feedback loop significantly. Much worse, it's really not clear what this test achieves. - The second element of its `pair=(debian-bug-875281.diff.json',)` argument is empty, does this mean it's comparing `debian-bug-875281.diff.json` with nothing?! That's not even possible on the command line and could explain why it's taking so long (all the time is spent in diffoscope main() method) - As of HEAD a93aa33d1bd1, the comment `# this test fails when you git revert -Xtheirs ccd926f` is wrong. The test keeps passing even after this revert. Workaround: `time pytest-3 -n 4 -k 'not '875281'` https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=875281