gh-94217: Skip import tests when _testcapi is a builtin (GH-94218)

(cherry picked from commit 0a40025)

Co-authored-by: Christian Heimes <christian@python.org>

Author: miss-islington

Lib/test/test_importlib/extension/test_finder.py

@@ -3,7 +3,7 @@
 machinery = util.import_importlib('importlib.machinery')
 
 import unittest
-import warnings
+import sys
 
 
 class FinderTests(abc.FinderTests):
@@ -13,6 +13,10 @@ class FinderTests(abc.FinderTests):
     def setUp(self):
         if not self.machinery.EXTENSION_SUFFIXES:
             raise unittest.SkipTest("Requires dynamic loading support.")
+        if util.EXTENSIONS.name in sys.builtin_module_names:
+            raise unittest.SkipTest(
+                f"{util.EXTENSIONS.name} is a builtin module"
+            )
 
     def find_spec(self, fullname):
         importer = self.machinery.FileFinder(util.EXTENSIONS.path,

Lib/test/test_importlib/extension/test_loader.py

@@ -20,6 +20,10 @@ class LoaderTests(abc.LoaderTests):
     def setUp(self):
         if not self.machinery.EXTENSION_SUFFIXES:
             raise unittest.SkipTest("Requires dynamic loading support.")
+        if util.EXTENSIONS.name in sys.builtin_module_names:
+            raise unittest.SkipTest(
+                f"{util.EXTENSIONS.name} is a builtin module"
+            )
         self.loader = self.machinery.ExtensionFileLoader(util.EXTENSIONS.name,
                                                          util.EXTENSIONS.file_path)
 
@@ -97,6 +101,10 @@ def setUp(self):
         if not self.machinery.EXTENSION_SUFFIXES:
             raise unittest.SkipTest("Requires dynamic loading support.")
         self.name = '_testmultiphase'
+        if self.name in sys.builtin_module_names:
+            raise unittest.SkipTest(
+                f"{self.name} is a builtin module"
+            )
         finder = self.machinery.FileFinder(None)
         self.spec = importlib.util.find_spec(self.name)
         assert self.spec