Failing test_text_proper_indentation

I'm having trouble figuring out why this test fails:

===================================================== FAILURES ======================================================
___________________________________________ test_text_proper_indentation ____________________________________________

capsys = <_pytest.capture.CaptureFixture object at 0x7f6113c905e0>

    @skip_unless_file_version_is_at_least("5.39")
    def test_text_proper_indentation(capsys):
        out = run(capsys, pair=("archive1.tar", "archive2.tar"))
    
>       assert out == get_data("archive12.diff.txt")
E       AssertionError: assert '--- archive1...         b.\n' == '--- archive1... -a\n│ │ +b\n'
E         Skipping 545 identical leading characters in diff, use -v to show
E           1 @@
E         - │ │ -a
E         - │ │ +b
E         + │ │ -00000000: 610a                                     a.
E         + │ │ +00000000: 620a                                     b.

tests/test_presenters.py:92: AssertionError
============================================== short test summary info ==============================================
FAILED tests/test_presenters.py::test_text_proper_indentation - AssertionError: assert '--- archive1...         b....
=============================== 1 failed, 310 passed, 165 skipped in 62.83s (0:01:02) ===============================
>>> ERROR: diffoscope: check failed
>>> diffoscope: Uninstalling dependencies...

This test is currently disabled by both the Arch Linux package and the Alpine Linux package.