Four tests fails without HOME

[mtelka]

Describe the bug

The following four tests fails without the HOME environment variable:

=========================== short test summary info ============================
FAILED pyfakefs/tests/fake_filesystem_test.py::FakePathModuleTest::test_expand_user
FAILED pyfakefs/tests/fake_filesystem_unittest_test.py::TestOtherFS::test_real_file_with_home
FAILED pyfakefs/tests/fake_pathlib_test.py::FakePathlibFileObjectPropertyTest::test_expanduser
FAILED pyfakefs/tests/fake_pathlib_test.py::FakePathlibFileObjectPropertyTest::test_home
=========== 4 failed, 1281 passed, 858 skipped, 4 xfailed in 17.86s ============

The log for three failures is like this:

_____________________ FakePathModuleTest.test_expand_user ______________________

self = <pyfakefs.tests.fake_filesystem_test.FakePathModuleTest testMethod=test_expand_user>

    def test_expand_user(self):
        if self.is_windows:
            self.assertEqual(
                self.path.expanduser("~"),
                self.os.environ["USERPROFILE"].replace("\\", "!"),
            )
        else:
            self.assertEqual(
                self.path.expanduser("~"),
>               self.os.environ["HOME"].replace("/", "!"),
            )

pyfakefs/tests/fake_filesystem_test.py:1073:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = environ({'LC_CTYPE': 'C.UTF-8', 'PYTHONPATH': '...stripped...', 'PYTEST_CURRENT_TEST': 'pyfakefs/tests/fake_filesystem_test.py::FakePathModuleTest::test_expand_user (call)'})
key = 'HOME'

    def __getitem__(self, key):
        try:
            value = self._data[self.encodekey(key)]
        except KeyError:
            # raise KeyError with the original key value
>           raise KeyError(key) from None
E           KeyError: 'HOME'

/usr/lib/python3.9/os.py:679: KeyError

The fourth test (TestOtherFS.test_real_file_with_home) fails with different error message, but the failure is caused by missing HOME too.

How To Reproduce

Run tests without the HOME variable set, for example via env -.

Your environment
Please run the following in the environment where the problem happened and
paste the output.

$ python -c "import platform; print(platform.platform())"
SunOS-5.11-i86pc-i386-64bit-ELF
$ python -c "import sys; print('Python', sys.version)"
Python 3.9.16 (main, Feb 19 2023, 15:42:40) 
[GCC 10.4.0]
$ python -c "from pyfakefs import __version__; print('pyfakefs', __version__)"
pyfakefs 5.2.4
$ python -c "import pytest; print('pytest', pytest.__version__)"
pytest 7.4.0
$

[mtelka]

I think this is regression from 5.2.3.

[mrbean-bremen]

Thanks, I will have a look!

[mrbean-bremen]

Ok, this is not a regression (the code has been there since 2016), just an issue of the test environment.
Has to be fixed in the tests.

[mtelka]

You are right. I just tried to run tests for 5.2.3 and they failed similarly. I noticed that when tests are run with the pytest-checkdocs plugin installed then all of them pass. Apparently, previously (the 5.2.3 version) I tested with the plugin installed and today (5.2.4) I tested with checkdocs uninstalled so it looked to me like a regression.

Thank you.