Change expected message for ValueError, fixing bug #126400
diff --git a/Lib/test/test_format.py b/Lib/test/test_format.py
index 4778a8b..f11eb54 100644
--- a/Lib/test/test_format.py
+++ b/Lib/test/test_format.py
@@ -197,5 +197,5 @@
 test_exc('abc %a', 1, ValueError,
          "unsupported format character 'a' (0x61) at index 5")
 test_exc(u'abc %\u3000', 1, ValueError,
-         "unsupported format character '\000' (0x3000) at index 5")
+         "unsupported format character '?' (0x3000) at index 5")