pyspacewar has a test suite written back when I still thought doctest modules were neat. It uses --doctest-modules and relies on some module-global setup/teardown specified in a @pytest.fixture(autouse=True).

This broke with the pytest 8.0.0 release. If I run

pytest src/pyspacewar/tests/ --setup-show

I can see that the autouse fixtures defined in my conftest.py are being called, but the autouse fixture in src/pyspacewar/tests/test_main.py (fake_game_ui) is not. This breaks the tests or makes them hang:

src/pyspacewar/tests/test_main.py 
        src/pyspacewar/tests/test_main.py::pyspacewar.tests.test_main.doctest_main (fixtures used: setUp)

Curiously, if I run just a single file or all the test files in the directory, this doesn't happen:

pytest src/pyspacewar/tests/*.py --setup-show

shows

...
src/pyspacewar/tests/test_main.py 
    SETUP    M fake_game_ui
        src/pyspacewar/tests/test_main.py::pyspacewar.tests.test_main.doctest_main (fixtures used: fake_game_ui, setUp).
    TEARDOWN M fake_game_ui
...

which is also what pytest 7.4.4 used to do.

I've verified by pip install "pytest<8" and pip install -U pytest that pytest being 7.4.4 vs 8.0.0 is the only difference between a working and a not-working tox environment. A full pip list is here:

Package    Version
---------- ----------
iniconfig  2.0.0
mock       5.1.0
packaging  23.2
pip        23.2.1
pluggy     1.4.0
pygame     2.5.2
pyspacewar 1.2.0.dev0
pytest     8.0.0

OS: Ubuntu 23.10.

I have not yet tried to produce a separate minimal example, but you should be able to quickly reproduce this if you

git clone https://github.com/mgedmin/pyspacewar
tox -e py312 --notest
.tox/py312/bin/pip install -U pytest    # because I pinned to <8 as a workaround for now
.tox/py312/bin/pytest src/pyspacewar/tests/ --setup-show