Fix

Author: StanFromIreland

Lib/test/test_zoneinfo/_support.py

@@ -33,6 +33,7 @@ def get_modules():
     one time — in other words, when using this function you will only ever
     get one copy of each module rather than a fresh import each time.
     """
+    import zoneinfo as c_module
 
     py_module = import_fresh_module("zoneinfo", blocked=["_zoneinfo"])
 

Lib/test/test_zoneinfo/test_zoneinfo.py

@@ -1915,8 +1915,8 @@ def test_exclude_posixrules(self):
 class CTestModule(TestModule):
     module = c_zoneinfo
 
-
-@unittest.skipIf(c_zoneinfo == py_zoneinfo,"zoneinfo C extension not available")
+@unittest.skipIf(__import__("sys").modules.get("_zoneinfo") is None,
+                 "_zoneinfo C module not available")
 class ExtensionBuiltTest(unittest.TestCase):
     """Smoke test to ensure that the C and Python extensions are both tested.