Intermittent CI failure: restore_working_directory FileNotFoundError

[simonw]

e.g. in https://github.com/simonw/datasette/runs/2754772233 - this is an intermittent error:

__________ ERROR at setup of test_hook_register_routes_render_message __________
[gw0] linux -- Python 3.8.10 /opt/hostedtoolcache/Python/3.8.10/x64/bin/python

tmpdir = local('/tmp/pytest-of-runner/pytest-0/popen-gw0/test_hook_register_routes_rend0')
request = <SubRequest 'restore_working_directory' for <Function test_hook_register_routes_render_message>>

    @pytest.fixture
    def restore_working_directory(tmpdir, request):
>       previous_cwd = os.getcwd()
E       FileNotFoundError: [Errno 2] No such file or directory

[simonw]

Stack Overflow: https://stackoverflow.com/a/49367679/6083

The answer was that os.chdir() had been set to the deleted directory by accident. The directory was missing, but the error happened (it seems) at the attempt to get it with os.getcwd().

[simonw]

I'm going to try removing that restore_working_directory fixture entirely.

[simonw]

That broke things. Here's how pytest-cov fixed a similar issue: pytest-dev/pytest-cov@7ccb178

See also nedbat/coveragepy#881 and pytest-dev/pytest-cov#306 and nedbat/coveragepy#824

[simonw]

That seems to have fixed it. I'd love to get rid of this restore_working_directory hack entirely.