Exclude pytest pathlib module from patching (#828)

- fixes some specific tests in namespace packages
- fixes #814

.github/workflows/testsuite.yml

@@ -116,6 +116,10 @@ jobs:
         run: |
           echo "$(python -m pytest pyfakefs/pytest_tests/pytest_plugin_failing_helper.py)" > ./testresult.txt
           python -m pytest pyfakefs/pytest_tests
+          if [[ '${{ matrix.pytest-version }}' > '3.0.0' ]]; then
+            cd pyfakefs/pytest_tests/ns_package
+            python -m pytest --log-cli-level=INFO test
+          fi
         shell: bash
 
   dependency-check:

CHANGES.md

@@ -6,6 +6,8 @@ The released versions correspond to PyPI releases.
 ### Fixes
 * Re-create temp directory if it had been created before on resetting file system
   (see [#814](../../issues/814)).
+* Exclude pytest `pathlib` modules from patching to avoid mixup of patched/unpatched
+  code (see [#814](../../issues/814)).
 
 ### Infrastructure
 * Added pytype check for non-test modules in CI (see [#599](../../issues/599)).

pyfakefs/pytest_plugin.py

@@ -13,8 +13,15 @@ def my_fakefs_test(fs):
 
 from pyfakefs.fake_filesystem_unittest import Patcher
 
+try:
+    from _pytest import pathlib
+except ImportError:
+    pathlib = None
+
 Patcher.SKIPMODULES.add(py)
 Patcher.SKIPMODULES.add(pytest)
+if pathlib is not None:
+    Patcher.SKIPMODULES.add(pathlib)
 
 
 @pytest.fixture

pyfakefs/pytest_tests/ns_package/test/ns_package/test/test_file.py

@@ -0,0 +1,7 @@
+import pyfakefs.fake_filesystem
+
+
+def test_foo(fs):
+    """Regression test for #814 - must run in namespace package with cli logging."""
+    fs.os = pyfakefs.fake_filesystem.OSType.WINDOWS
+    assert True