diff -r 5e916decdc74 Lib/test/test_unicode.py
--- a/Lib/test/test_unicode.py	Mon Nov 21 23:12:56 2011 +0100
+++ b/Lib/test/test_unicode.py	Tue Nov 22 03:40:56 2011 +0300
@@ -912,6 +912,13 @@
         self.assertRaises(TypeError, '{a'.format_map)
         self.assertRaises(TypeError, '}a'.format_map)
 
+        self.assertRaises(ValueError, '{'.format_map, {})
+        self.assertRaises(ValueError, '}'.format_map, {})
+        self.assertRaises(ValueError, 'a{'.format_map, {})
+        self.assertRaises(ValueError, 'a}'.format_map, {})
+        self.assertRaises(ValueError, '{a'.format_map, {})
+        self.assertRaises(ValueError, '}a'.format_map, {})
+
         # issue #12579: can't supply positional params to format_map
         self.assertRaises(ValueError, '{}'.format_map, {'a' : 2})
         self.assertRaises(ValueError, '{}'.format_map, 'a')