excellent place for assertRaises

Lib/test/test_descr.py

@@ -1631,12 +1631,7 @@ order (MRO) for bases """
             for attr, obj in env.items():
                 setattr(X, attr, obj)
             setattr(X, name, ErrDescr())
-            try:
-                runner(X())
-            except MyException:
-                pass
-            else:
-                self.fail("{0!r} didn't raise".format(name))
+            self.assertRaises(MyException, runner, X())
 
     def test_specials(self):
         # Testing special operators...