diff -r 0ebc9005cb00 Lib/test/test_collections.py
--- a/Lib/test/test_collections.py	Thu May 30 21:08:49 2013 -0400
+++ b/Lib/test/test_collections.py	Fri May 31 16:09:32 2013 +0800
@@ -930,11 +930,12 @@
                     update_test,
                     Counter(words),
                     ]):
-            msg = (i, dup, words)
-            self.assertTrue(dup is not words)
-            self.assertEqual(dup, words)
-            self.assertEqual(len(dup), len(words))
-            self.assertEqual(type(dup), type(words))
+            msg = "iteration: %s, counter from loop: %s, counter: %s" %\
+                (i, dup, words)
+            self.assertTrue(dup is not words, msg)
+            self.assertEqual(dup, words, msg)
+            self.assertEqual(len(dup), len(words), msg)
+            self.assertEqual(type(dup), type(words), msg)
 
     def test_copy_subclass(self):
         class MyCounter(Counter):
@@ -1226,11 +1227,13 @@
                     update_test,
                     OrderedDict(od),
                     ]):
-            self.assertTrue(dup is not od)
-            self.assertEqual(dup, od)
-            self.assertEqual(list(dup.items()), list(od.items()))
-            self.assertEqual(len(dup), len(od))
-            self.assertEqual(type(dup), type(od))
+            msg = ("iteration: %s, ordered dict from loop: %s, "
+                "ordered dict: %s") % (i, dup, od)
+            self.assertTrue(dup is not od, msg)
+            self.assertEqual(dup, od, msg)
+            self.assertEqual(list(dup.items()), list(od.items()), msg)
+            self.assertEqual(len(dup), len(od), msg)
+            self.assertEqual(type(dup), type(od), msg)
 
     def test_yaml_linkage(self):
         # Verify that __reduce__ is setup in a way that supports PyYAML's dump() feature.