Bug#1024335: diffoscope: FTBFS against python 3.11

[Dan Bungert]

Package: diffoscope
Severity: normal
User: ubuntu-devel at lists.ubuntu.com
Usertags: origin-ubuntu lunar

Dear Maintainer,

This bug report was also filed in Ubuntu and can be found at
https://launchpad.net/bugs/1996926

diffoscope will FTBFS in tests when run with python 3.11.  Can be observed both
on Debian Sid and Ubuntu Lunar.

https://autopkgtest.ubuntu.com/results/autopkgtest-lunar/lunar/amd64/d/diffoscope/20221103_074104_c1d72@/log.gz

(that log also shows a lxml error, but that problem goes away when triggering
tests with lxml from proposed)

__________________________________ test_diff __________________________________

differences = []

    @skip_unless_file_version_is_at_least("5.39")
    @skipif(
        sys.version_info < (3, 8),
        reason="Python 3.7 cannot de-marshal test1.pyc-renamed",
    )
    def test_diff(differences):
        assert_diff_startswith(
>           differences[0],
            "pyc_expected_diff",
        )
E       IndexError: list index out of range

differences = []

tests/comparators/test_python.py:61: IndexError