Index: Lib/test/test___all__.py
===================================================================
--- Lib/test/test___all__.py	(revision 88256)
+++ Lib/test/test___all__.py	(working copy)
@@ -38,8 +38,10 @@
         if "__builtins__" in names:
             del names["__builtins__"]
         keys = set(names)
-        all = set(sys.modules[modname].__all__)
-        self.assertEqual(keys, all)
+        all_list = sys.modules[modname].__all__
+        all_set = set(all_list)
+        self.assertCountEqual(all_set, all_list, "in module {}".format(modname))
+        self.assertEqual(keys, all_set, "in module {}".format(modname))
 
     def walk_modules(self, basedir, modpath):
         for fn in sorted(os.listdir(basedir)):