Close issue #6210: Implement PEP 409
diff --git a/Lib/test/test_exceptions.py b/Lib/test/test_exceptions.py
index a7683ac..91d85ef 100644
--- a/Lib/test/test_exceptions.py
+++ b/Lib/test/test_exceptions.py
@@ -387,19 +387,36 @@
def testChainingAttrs(self):
e = Exception()
- self.assertEqual(e.__context__, None)
- self.assertEqual(e.__cause__, None)
+ self.assertIsNone(e.__context__)
+ self.assertIs(e.__cause__, Ellipsis)
e = TypeError()
- self.assertEqual(e.__context__, None)
- self.assertEqual(e.__cause__, None)
+ self.assertIsNone(e.__context__)
+ self.assertIs(e.__cause__, Ellipsis)
class MyException(EnvironmentError):
pass
e = MyException()
- self.assertEqual(e.__context__, None)
- self.assertEqual(e.__cause__, None)
+ self.assertIsNone(e.__context__)
+ self.assertIs(e.__cause__, Ellipsis)
+
+ def testChainingDescriptors(self):
+ try:
+ raise Exception()
+ except Exception as exc:
+ e = exc
+
+ self.assertIsNone(e.__context__)
+ self.assertIs(e.__cause__, Ellipsis)
+
+ e.__context__ = NameError()
+ e.__cause__ = None
+ self.assertIsInstance(e.__context__, NameError)
+ self.assertIsNone(e.__cause__)
+
+ e.__cause__ = Ellipsis
+ self.assertIs(e.__cause__, Ellipsis)
def testKeywordArgs(self):
# test that builtin exception don't take keyword args,