From: Oren Milman <orenmn@gmail.com>
Date: Tue, 7 Nov 2017 00:17:54 +0000 (+0200)
Subject: [2.7] bpo-31271: Fix an assertion failure in io.TextIOWrapper.write. (GH-3201) (... 
X-Git-Tag: v2.7.15rc1~138
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=30537698b607d53fa9ce18522abb88469d5814b6;p=thirdparty%2FPython%2Fcpython.git

[2.7] bpo-31271: Fix an assertion failure in io.TextIOWrapper.write. (GH-3201) (#3951)
---

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 3dc6e9ffcac1..ea5ec656f755 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -2666,6 +2666,22 @@ class TextIOWrapperTest(unittest.TestCase):
         t = self.TextIOWrapper(NonbytesStream('a'))
         self.assertEqual(t.read(), u'a')
 
+    def test_illegal_encoder(self):
+        # bpo-31271: A TypeError should be raised in case the return value of
+        # encoder's encode() is invalid.
+        class BadEncoder:
+            def encode(self, dummy):
+                return u'spam'
+        def get_bad_encoder(dummy):
+            return BadEncoder()
+        rot13 = codecs.lookup("rot13")
+        with support.swap_attr(rot13, '_is_text_encoding', True), \
+             support.swap_attr(rot13, 'incrementalencoder', get_bad_encoder):
+            t = io.TextIOWrapper(io.BytesIO(b'foo'), encoding="rot13")
+        with self.assertRaises(TypeError):
+            t.write('bar')
+            t.flush()
+
     def test_illegal_decoder(self):
         # Issue #17106
         # Bypass the early encoding check added in issue 20404