Remove the need to import the "undefined" module in test

- the module is not maintained and very trivial

.github/workflows/testsuite.yml

@@ -116,7 +116,7 @@ jobs:
         run: |
           pip install -r requirements.txt
           pip install -U pytest==${{ matrix.pytest-version }}
-          pip install opentimelineio undefined pandas parquet pyarrow
+          pip install opentimelineio pandas parquet pyarrow
           pip install -e .
           if [[ '${{ matrix.pytest-version }}' == '4.0.2' ]]; then
              pip install -U attrs==19.1.0

CHANGES.md

@@ -9,6 +9,10 @@ The released versions correspond to PyPI releases.
 * removed the argument `module_cleanup_mode`, that was introduced as a temporary workaround
   in the previous version - related problems shall be handled using a cleanup handler
 
+### Enhancements
+* added support for `O_NOFOLLOW` and `O_DIRECTORY` flags in `os.open`
+  (see [#972](../../issues/972) and [#974](../../issues/974))
+
 ### Fixes
 * fixed a specific problem on reloading a pandas-related module (see [#947](../../issues/947)),
   added possibility for unload hooks for specific modules
@@ -26,9 +30,10 @@ The released versions correspond to PyPI releases.
 * fixed permission problem with `shutil.rmtree` if emulating Windows under POSIX
   (see [#979](../../issues/979))
 
-### Enhancements
-* added support for `O_NOFOLLOW` and `O_DIRECTORY` flags in `os.open`
-  (see [#972](../../issues/972) and [#974](../../issues/974))
+### Infrastructure
+* replace `undefined` by own minimal implementation to avoid importing it
+  (see [#981](../../discussions/981))
+
 
 ## [Version 5.3.5](https://pypi.python.org/pypi/pyfakefs/5.3.5) (2024-01-30)
 Fixes a regression.

pyfakefs/pytest_tests/pytest_fixture_test.py

@@ -13,10 +13,10 @@
 # Example for a test using a custom pytest fixture with an argument to Patcher
 
 import pytest
-import undefined
 
 import pyfakefs.pytest_tests.example as example
 from pyfakefs.fake_filesystem_unittest import Patcher
+from pyfakefs.pytest_tests import unhashable
 
 
 @pytest.mark.xfail
@@ -42,10 +42,9 @@ def test_example_file_passing_using_patcher():
         check_that_example_file_is_in_fake_fs()
 
 
-def test_undefined(fs):
+def test_unhashable(fs):
     # regression test for #923
-    with pytest.raises(NotImplementedError):
-        print(undefined)
+    print(unhashable)
 
 
 def check_that_example_file_is_in_fake_fs():

pyfakefs/pytest_tests/pytest_reload_pandas_test.py

@@ -5,14 +5,22 @@
 from pathlib import Path
 
 import pandas as pd
+import pytest
 
+try:
+    import parquet
+except ImportError:
+    parquet = None
 
+
+@pytest.mark.skipif(parquet is None, "parquet not installed")
 def test_1(fs):
     dir_ = Path(__file__).parent / "data"
     fs.add_real_directory(dir_)
     pd.read_parquet(dir_ / "test.parquet")
 
 
+@pytest.mark.skipif(parquet is None, "parquet not installed")
 def test_2():
     dir_ = Path(__file__).parent / "data"
     pd.read_parquet(dir_ / "test.parquet")

pyfakefs/pytest_tests/unhashable.py

@@ -0,0 +1,19 @@
+import sys
+import types
+
+
+class Unhashable(types.ModuleType):
+    """
+    Unhashable module, used for regression test for  #923.
+    """
+
+    @property
+    def Unhashable(self):
+        return self
+
+    def __eq__(self, other):
+        raise NotImplementedError("Cannot compare unhashable")
+
+
+if sys.modules[__name__] is not Unhashable:
+    sys.modules[__name__] = Unhashable("unhashable")