[Python-checkins] bpo-32618: Fix test_mutatingdecodehandler not testing test.mutating (GH-5269) (#5285)

[Xiang Zhang]

https://github.com/python/cpython/commit/6abbf14a876ee1e04d1493bb27025f2f0aa56430
commit: 6abbf14a876ee1e04d1493bb27025f2f0aa56430
branch: 3.6
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Xiang Zhang <angwerzx at 126.com>
date: 2018-01-23T23:47:15+08:00
summary:

bpo-32618: Fix test_mutatingdecodehandler not testing test.mutating (GH-5269) (#5285)

It should test both test.replacing and test.mutating instead of test test.replacing twice.
(cherry picked from commit 370d04d1dcca50a52d59f40aff4d11434f71df6b)

files:
M Lib/test/test_codeccallbacks.py

diff --git a/Lib/test/test_codeccallbacks.py b/Lib/test/test_codeccallbacks.py
index 6a3e9932656..0c066e633fa 100644
--- a/Lib/test/test_codeccallbacks.py
+++ b/Lib/test/test_codeccallbacks.py
@@ -1032,7 +1032,7 @@ def replacing(exc):
 
         def mutating(exc):
             if isinstance(exc, UnicodeDecodeError):
-                exc.object[:] = b""
+                exc.object = b""
                 return ("\u4242", 0)
             else:
                 raise TypeError("don't know how to handle %r" % exc)
@@ -1042,8 +1042,7 @@ def mutating(exc):
         with test.support.check_warnings():
             # unicode-internal has been deprecated
             for (encoding, data) in baddata:
-                with self.assertRaises(TypeError):
-                    data.decode(encoding, "test.replacing")
+                self.assertEqual(data.decode(encoding, "test.mutating"), "\u4242")
 
     def test_fake_error_class(self):
         handlers = [