commit dea46ec9654a6412e74a6f8dfbdf97ff97516670
author Raymond Hettinger <python@rcn.com> Mon May 26 00:43:27 2014 -0700
committer Raymond Hettinger <python@rcn.com> Mon May 26 00:43:27 2014 -0700
tree 6e157f543c738ecdf463a53afde142cb007a660e
parent dd5e53a086fcabc84ee1ac96b98057437863973a

Issue #21481:  Teach argparse equality tests to return NotImplemented when comparing to unknown types.

Lib/test/test_argparse.py

diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 5c77ec8..8a4fdb9 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -4551,6 +4551,12 @@
         self.assertTrue(ns2 != ns3)
         self.assertTrue(ns2 != ns4)
 
+    def test_equality_returns_notimplemeted(self):
+        # See issue 21481
+        ns = argparse.Namespace(a=1, b=2)
+        self.assertIs(ns.__eq__(None), NotImplemented)
+        self.assertIs(ns.__ne__(None), NotImplemented)
+
 
 # ===================
 # File encoding tests