sys.platform on Mac OS X is now "darwin", without any version number appended.
This should probably go into NEWS (who's responsible for that?).
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 3bb2668..25cabff 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -619,7 +619,7 @@
         test_winreg
         test_winsound
         """,
-    'darwin1':
+    'darwin':
         """
         test_al
         test_cd