Added test for copy_reg rename.
Added note to documentation about copy_reg rename.
diff --git a/Lib/test/test_py3kwarn.py b/Lib/test/test_py3kwarn.py
index ddf38ad..40f7b19 100644
--- a/Lib/test/test_py3kwarn.py
+++ b/Lib/test/test_py3kwarn.py
@@ -183,7 +183,7 @@
 
 class TestStdlibRenames(unittest.TestCase):
 
-    renames = {}
+    renames = {'copy_reg': 'copyreg'}
 
     def check_rename(self, module_name, new_module_name):
         """Make sure that: