Merge changes to syncronize the 6.4 release with downstream CPython changes.

Ref python/cpython#123028.

Author: jaraco

importlib_resources/tests/compat/py39.py

@@ -8,3 +8,6 @@
     'modules_setup', 'modules_cleanup', 'DirsOnSysPath'
 )
 os_helper = try_import('os_helper') or from_test_support('temp_dir')
+warnings_helper = try_import('warnings_helper') or from_test_support(
+    'ignore_warnings', 'check_warnings'
+)

importlib_resources/tests/test_functional.py

@@ -1,13 +1,8 @@
 import unittest
 import os
-import contextlib
 import importlib
 
-try:
-    from test.support.warnings_helper import ignore_warnings, check_warnings
-except ImportError:
-    # older Python versions
-    from test.support import ignore_warnings, check_warnings
+from .compat.py39 import warnings_helper
 
 import importlib_resources as resources
 
@@ -181,32 +176,32 @@ def test_is_resource(self):
             self.assertTrue(is_resource(self.anchor02, *path_parts))
 
     def test_contents(self):
-        with check_warnings((".*contents.*", DeprecationWarning)):
+        with warnings_helper.check_warnings((".*contents.*", DeprecationWarning)):
             c = resources.contents(self.anchor01)
         self.assertGreaterEqual(
             set(c),
             {'utf-8.file', 'utf-16.file', 'binary.file', 'subdirectory'},
         )
-        with contextlib.ExitStack() as cm:
-            cm.enter_context(self.assertRaises(OSError))
-            cm.enter_context(check_warnings((".*contents.*", DeprecationWarning)))
-
+        with self.assertRaises(OSError), warnings_helper.check_warnings((
+            ".*contents.*",
+            DeprecationWarning,
+        )):
             list(resources.contents(self.anchor01, 'utf-8.file'))
 
         for path_parts in self._gen_resourcetxt_path_parts():
-            with contextlib.ExitStack() as cm:
-                cm.enter_context(self.assertRaises(OSError))
-                cm.enter_context(check_warnings((".*contents.*", DeprecationWarning)))
-
+            with self.assertRaises(OSError), warnings_helper.check_warnings((
+                ".*contents.*",
+                DeprecationWarning,
+            )):
                 list(resources.contents(self.anchor01, *path_parts))
-        with check_warnings((".*contents.*", DeprecationWarning)):
+        with warnings_helper.check_warnings((".*contents.*", DeprecationWarning)):
             c = resources.contents(self.anchor01, 'subdirectory')
         self.assertGreaterEqual(
             set(c),
             {'binary.file'},
         )
 
-    @ignore_warnings(category=DeprecationWarning)
+    @warnings_helper.ignore_warnings(category=DeprecationWarning)
     def test_common_errors(self):
         for func in (
             resources.read_text,