Test error on Ubuntu: Module-scoped fake filesystem fixture not found

[nicolashainaux]

Describe the bug
If I run pytest -vv -x, (-vv is to get verbose output, -x is to stop pytest at first error) I get the following error:

pyfakefs/tests/fake_filesystem_unittest_test.py::TestModuleScopedFsWithTmpdir::test_fail ERROR                                                                                                 [ 21%]

=============================================================================================== ERRORS ===============================================================================================
______________________________________________________________________ ERROR at setup of TestModuleScopedFsWithTmpdir.test_fail ______________________________________________________________________
file /home/sophie/.local/dev/pyfakefs/pyfakefs/tests/fake_filesystem_unittest_test.py, line 889
      def test_fail(self, fs_module):
E       fixture 'fs_module' not found
>       available fixtures: cache, capfd, capfdbinary, caplog, capsys, capsysbinary, cov, doctest_namespace, mock, mocker, monkeypatch, no_cover, pytestconfig, record_property, record_testsuite_property, record_xml_attribute, recwarn, test_internal, tmp_path, tmp_path_factory, tmpdir, tmpdir_factory
>       use 'pytest --fixtures [testpath]' for help on them.

/home/sophie/.local/dev/pyfakefs/pyfakefs/tests/fake_filesystem_unittest_test.py:889
====================================================================================== short test summary info =======================================================================================
ERROR pyfakefs/tests/fake_filesystem_unittest_test.py::TestModuleScopedFsWithTmpdir::test_fail
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
======================================================================== 403 passed, 39 skipped, 4 xfailed, 1 error in 2.06s =========================================================================

I followed the given advice (hence pytest --fixtures pyfakefs/pytest_plugin.py), but everything was green (it found the module-scoped fixture):

---------------------------------------------------------------------------- fixtures defined from pyfakefs.pytest_plugin ----------------------------------------------------------------------------
fs -- pyfakefs/pytest_plugin.py:21
    Fake filesystem. 

fs_module [module scope] -- pyfakefs/pytest_plugin.py:34
    Module-scoped fake filesystem fixture. 

fs_session [session scope] -- pyfakefs/pytest_plugin.py:46
    Session-scoped fake filesystem fixture. 

First try was with older pytest (the focal packaged one, 4.6.9), but I have got the same result with latest pytest (>7.0).

I am not 100% sure this is a bug: maybe I haven't run the right tests? Or not the right way?
I have looked for the same test in your github actions (Latest Ubuntu, python3.8), but I have not found it.

How To Reproduce
Just run pytest -vv -x in the cloned repo (master branch)

Your environment

Linux-5.4.0-122-generic-x86_64-with-glibc2.31

Python 3.8.10 (default, Mar 15 2022, 12:22:08) 
[GCC 9.4.0]

pyfakefs 4.7.dev0

[mrbean-bremen]

Looks like I put this test into the wrong module. The test assumes that pyfakefs is installed as a package, so that the fixtures are registered. This is only assumed for the pytest_plugin_test module where this test belongs, and which is not run by default - I will move it there. I did not notice this, as the CI tests do install pyfakefs, and I locally use a developer install.

Thanks for the report - I will fix this in master, and then look at the other Pytho 3.11 related problems that have been reported before making a patch release.

[mrbean-bremen]

Please check if it works with current master.

[nicolashainaux]

Thanks for your quick patch!
Unfortunately, it still fails the same way. I installed pyfakefs in a venv, to make sure it was installed (python setup.py install and python setup.py develop is the right way, I guess), but still:

(py38) pyfakefs [master|+1*330] $ pytest -vv -x
=============================================== test session starts ================================================
platform linux -- Python 3.8.10, pytest-7.1.2, pluggy-0.13.0 -- /usr/bin/python3
cachedir: .pytest_cache
rootdir: /home/sophie/.local/dev/pyfakefs
plugins: mock-1.10.4, cov-2.8.1
collected 2068 items                                                                                               

pyfakefs/pytest_tests/pytest_check_failed_plugin_test.py::test_failed_testresult_stacktrace SKIPPED (Only run in CI tests) [  0%]
pyfakefs/pytest_tests/pytest_fixture_param_test.py::test_example_file_failing XFAIL                          [  0%]
pyfakefs/pytest_tests/pytest_fixture_param_test.py::test_example_file_passing_using_parametrized_fixture[fs0] PASSED [  0%]
pyfakefs/pytest_tests/pytest_fixture_param_test.py::test_twice_chdir PASSED                                  [  0%]
pyfakefs/pytest_tests/pytest_fixture_test.py::test_example_file_failing XFAIL                                [  0%]
pyfakefs/pytest_tests/pytest_fixture_test.py::test_example_file_passing_using_fixture PASSED                 [  0%]
pyfakefs/pytest_tests/pytest_fixture_test.py::test_example_file_passing_using_patcher PASSED                 [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::test_fs_fixture PASSED                                          [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::test_fs_fixture_alias PASSED                                    [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::test_both_fixtures PASSED                                       [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::test_pause_resume PASSED                                        [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::test_pause_resume_contextmanager PASSED                         [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py::TestModuleScopedFsWithTmpdir::test_fail ERROR                   [  0%]

====================================================== ERRORS ======================================================
_____________________________ ERROR at setup of TestModuleScopedFsWithTmpdir.test_fail _____________________________
file /home/sophie/.local/dev/pyfakefs/pyfakefs/pytest_tests/pytest_plugin_test.py, line 62
      def test_fail(self, fs_module):
E       fixture 'fs_module' not found
>       available fixtures: cache, capfd, capfdbinary, caplog, capsys, capsysbinary, cov, doctest_namespace, fake_filesystem, fs, fs_reload_example, mock, mocker, monkeypatch, no_cover, pytestconfig, record_property, record_testsuite_property, record_xml_attribute, recwarn, test_internal, tmp_path, tmp_path_factory, tmpdir, tmpdir_factory
>       use 'pytest --fixtures [testpath]' for help on them.

/home/sophie/.local/dev/pyfakefs/pyfakefs/pytest_tests/pytest_plugin_test.py:62
============================================= short test summary info ==============================================
ERROR pyfakefs/pytest_tests/pytest_plugin_test.py::TestModuleScopedFsWithTmpdir::test_fail
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
================================= 9 passed, 1 skipped, 2 xfailed, 1 error in 0.54s =================================

[mrbean-bremen]

Ok, thank you - now I understood the problem, I fixed only half of it. I had an extra import for fs added in the conftest.py. This allowed these tests to to run without pyfakefs installed, and I forgot to add the same for fs_module. I probably have to remove installing the pyfakefs package in the CI tests to find these kind of problems. Thanks again!

[mrbean-bremen]

Ok, second try - please check again!

[nicolashainaux]

Well, the tests do pass, but there's a strange exception at the end (sophie being the current user name):

pyfakefs [master|+1*330] $ pytest -x
=========================================================== test session starts ============================================================
platform linux -- Python 3.8.10, pytest-7.1.2, pluggy-0.13.0
rootdir: /home/sophie/.local/dev/pyfakefs
plugins: mock-1.10.4, cov-2.8.1
collected 2068 items                                                                                                                       

pyfakefs/pytest_tests/pytest_check_failed_plugin_test.py s                                                                           [  0%]
pyfakefs/pytest_tests/pytest_fixture_param_test.py x..                                                                               [  0%]
pyfakefs/pytest_tests/pytest_fixture_test.py x..                                                                                     [  0%]
pyfakefs/pytest_tests/pytest_plugin_test.py ......                                                                                   [  0%]
pyfakefs/tests/dynamic_patch_test.py .....                                                                                           [  0%]
pyfakefs/tests/example_test.py .......s                                                                                              [  1%]
pyfakefs/tests/fake_filesystem_glob_test.py .........                                                                                [  1%]
pyfakefs/tests/fake_filesystem_shutil_test.py ................s...ssssssssssssssssssssss...........sssssssssss                       [  4%]
pyfakefs/tests/fake_filesystem_test.py ............................................................................................. [  9%]
.............................................s.................................s.................................................... [ 15%]
......................................                                                                                               [ 17%]
pyfakefs/tests/fake_filesystem_unittest_test.py .........................x...............................x.......................... [ 21%]
s                                                                                                                                    [ 21%]
pyfakefs/tests/fake_filesystem_vs_real_test.py ...........................                                                           [ 22%]
pyfakefs/tests/fake_open_test.py .......................................................................ssssssssssssssssssssssssssss [ 27%]
sssssssssssssssssssssssssssssssssssssssssss...sss..sss............ssssssssssss..........ssssssssss.....s..ssssssss.....sssss.....sss [ 34%]
..ss.....sssss..................ssssssssssssssssss                                                                                   [ 36%]
pyfakefs/tests/fake_os_test.py ..................................................................................................... [ 41%]
.................................................................................................................................... [ 47%]
................................................ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss [ 54%]
ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss [ 60%]
sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss................................................................... [ 66%]
................sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss.................s............... [ 73%]
....................s......sssssssssssssssssssssssssssssssssssssssssssssssss...........sssssssssss.................................. [ 79%]
....ssssssssssssss............ssssssssssssss............ssssssssssssss............ssssssssssssss.......sss                           [ 84%]
pyfakefs/tests/fake_pathlib_test.py ....s.sssssssssssssss.s......sssssssss.s..........s....sssssssssssssssss...ss........s.......... [ 89%]
.sssssssssssssssssssssssssss.......................................s...sssssssssssssssssssssssssssssssssssssssssss.....              [ 95%]
pyfakefs/tests/fake_stat_time_test.py .......sssssss........ssssssss.......sssssss........ssssssss.....sssss......ssssss             [ 99%]
pyfakefs/tests/fake_tempfile_test.py ........                                                                                        [ 99%]
pyfakefs/tests/mox3_stubout_test.py .........                                                                                        [100%]

=============================================== 1239 passed, 825 skipped, 4 xfailed in 5.70s ===============================================
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 2210, in get_object_from_normpath
    target = target.get_entry(component)  # type: ignore
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 733, in get_entry
    return self.entries[to_string(pathname_name)]
KeyError: 'pytest-of-sophie'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/sophie/.local/lib/python3.8/site-packages/_pytest/pathlib.py", line 342, in cleanup_numbered_dir
    for path in cleanup_candidates(root, prefix, keep):
  File "/home/sophie/.local/lib/python3.8/site-packages/_pytest/pathlib.py", line 328, in cleanup_candidates
    max_existing = max(map(parse_num, find_suffixes(root, prefix)), default=-1)
  File "/home/sophie/.local/lib/python3.8/site-packages/_pytest/pathlib.py", line 170, in extract_suffixes
    for p in iter:
  File "/home/sophie/.local/lib/python3.8/site-packages/_pytest/pathlib.py", line 158, in find_prefixed
    for x in root.iterdir():
  File "/usr/lib/python3.8/pathlib.py", line 1122, in iterdir
    for name in self._accessor.listdir(self):
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_pathlib.py", line 62, in _wrapped
    return strfunc(pathobj.filesystem, str(pathobj), *args, **kwargs)
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 3382, in listdir
    directory = self.confirmdir(target_directory)
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 3288, in confirmdir
    directory = cast(FakeDirectory, self.resolve(target_directory))
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 2265, in resolve
    return self.get_object_from_normpath(self.resolve_path(
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 2215, in get_object_from_normpath
    self.raise_os_error(errno.ENOENT, path)
  File "/home/sophie/.local/dev/pyfakefs/pyfakefs/fake_filesystem.py", line 1098, in raise_os_error
    raise OSError(err_no, message, filename)
FileNotFoundError: [Errno 2] No such file or directory in the fake filesystem: '/tmp/pytest-of-sophie'

[mrbean-bremen]

Ok, thank you - the same has been reported by another user, and I'm not sure yet was causes this (though I have an idea where this comes from). I won't have more time today to investigate this, will have another look tomorrow evening. I have made a patch release with the current version (mainly because of the Python 3.11 fix), and if I can fix this, I can probably make another one. Thanks for your fast responses - I much appreciate this kind of fast feedback!

[nicolashainaux]

Thank you for your quick answers too!
I'll answer as quick as possible. Sometimes it can't be as quick as I wish (tonight I'm not sure, maybe it'll be late).

[mrbean-bremen]

I removed the offending test, will reopen the respective issue to handle this. The error should be gone now - I will publish a new patch release soon. Edit: done.