That test was never run (since thread has been renamed to _thread in 3.x)

Lib/test/test_threading_local.py

@@ -137,15 +137,9 @@ def test_main():
     suite.addTest(unittest.makeSuite(ThreadLocalTest))
     suite.addTest(unittest.makeSuite(PyThreadingLocalTest))
 
-    try:
-        from thread import _local
-    except ImportError:
-        pass
-    else:
-        import _threading_local
     local_orig = _threading_local.local
     def setUp(test):
-            _threading_local.local = _local
+        _threading_local.local = _thread._local
     def tearDown(test):
         _threading_local.local = local_orig
     suite.addTest(DocTestSuite('_threading_local',