Make all the multibyte codec tests pass.
Changes to io.py, necessary to make this work:
- Redid io.StringIO as a TextIOWrapper on top of a BytesIO instance.
- Got rid of _MemoryIOMixin, folding it into BytesIO instead.
- The read() functions that take -1 to mean "eveything" now also take None.
- Added readline() support to BufferedIOBase. :-(
diff --git a/Lib/test/test_multibytecodec.py b/Lib/test/test_multibytecodec.py
index 3725f9e..f41ad34 100644
--- a/Lib/test/test_multibytecodec.py
+++ b/Lib/test/test_multibytecodec.py
@@ -7,7 +7,7 @@
 from test import test_support
 from test import test_multibytecodec_support
 from test.test_support import TESTFN
-import unittest, StringIO, codecs, sys, os
+import unittest, io, codecs, sys, os
 
 ALL_CJKENCODINGS = [
 # _codecs_cn
@@ -30,13 +30,13 @@
 
     def test_nullcoding(self):
         for enc in ALL_CJKENCODINGS:
-            self.assertEqual(''.decode(enc), '')
-            self.assertEqual(str('', enc), '')
-            self.assertEqual(''.encode(enc), '')
+            self.assertEqual(b''.decode(enc), '')
+            self.assertEqual(str(b'', enc), '')
+            self.assertEqual(''.encode(enc), b'')
 
     def test_str_decode(self):
         for enc in ALL_CJKENCODINGS:
-            self.assertEqual('abcd'.encode(enc), 'abcd')
+            self.assertEqual('abcd'.encode(enc), b'abcd')
 
     def test_errorcallback_longindex(self):
         dec = codecs.getdecoder('euc-kr')
@@ -48,7 +48,7 @@
     def test_codingspec(self):
         try:
             for enc in ALL_CJKENCODINGS:
-                print('# coding:', enc, file=open(TESTFN, 'w'))
+                print('# coding:', enc, file=io.open(TESTFN, 'w'))
                 execfile(TESTFN)
         finally:
             os.unlink(TESTFN)
@@ -59,13 +59,13 @@
         # cp949 encoder isn't stateful at all.
         encoder = codecs.getincrementalencoder('cp949')()
         self.assertEqual(encoder.encode('\ud30c\uc774\uc36c \ub9c8\uc744'),
-                         '\xc6\xc4\xc0\xcc\xbd\xe3 \xb8\xb6\xc0\xbb')
+                         b'\xc6\xc4\xc0\xcc\xbd\xe3 \xb8\xb6\xc0\xbb')
         self.assertEqual(encoder.reset(), None)
         self.assertEqual(encoder.encode('\u2606\u223c\u2606', True),
-                         '\xa1\xd9\xa1\xad\xa1\xd9')
+                         b'\xa1\xd9\xa1\xad\xa1\xd9')
         self.assertEqual(encoder.reset(), None)
-        self.assertEqual(encoder.encode('', True), '')
-        self.assertEqual(encoder.encode('', False), '')
+        self.assertEqual(encoder.encode('', True), b'')
+        self.assertEqual(encoder.encode('', False), b'')
         self.assertEqual(encoder.reset(), None)
 
     def test_stateful(self):
@@ -75,29 +75,29 @@
         #   U+0300 => ABDC
 
         encoder = codecs.getincrementalencoder('jisx0213')()
-        self.assertEqual(encoder.encode('\u00e6\u0300'), '\xab\xc4')
-        self.assertEqual(encoder.encode('\u00e6'), '')
-        self.assertEqual(encoder.encode('\u0300'), '\xab\xc4')
-        self.assertEqual(encoder.encode('\u00e6', True), '\xa9\xdc')
+        self.assertEqual(encoder.encode('\u00e6\u0300'), b'\xab\xc4')
+        self.assertEqual(encoder.encode('\u00e6'), b'')
+        self.assertEqual(encoder.encode('\u0300'), b'\xab\xc4')
+        self.assertEqual(encoder.encode('\u00e6', True), b'\xa9\xdc')
 
         self.assertEqual(encoder.reset(), None)
-        self.assertEqual(encoder.encode('\u0300'), '\xab\xdc')
+        self.assertEqual(encoder.encode('\u0300'), b'\xab\xdc')
 
-        self.assertEqual(encoder.encode('\u00e6'), '')
-        self.assertEqual(encoder.encode('', True), '\xa9\xdc')
-        self.assertEqual(encoder.encode('', True), '')
+        self.assertEqual(encoder.encode('\u00e6'), b'')
+        self.assertEqual(encoder.encode('', True), b'\xa9\xdc')
+        self.assertEqual(encoder.encode('', True), b'')
 
     def test_stateful_keep_buffer(self):
         encoder = codecs.getincrementalencoder('jisx0213')()
-        self.assertEqual(encoder.encode('\u00e6'), '')
+        self.assertEqual(encoder.encode('\u00e6'), b'')
         self.assertRaises(UnicodeEncodeError, encoder.encode, '\u0123')
-        self.assertEqual(encoder.encode('\u0300\u00e6'), '\xab\xc4')
+        self.assertEqual(encoder.encode('\u0300\u00e6'), b'\xab\xc4')
         self.assertRaises(UnicodeEncodeError, encoder.encode, '\u0123')
         self.assertEqual(encoder.reset(), None)
-        self.assertEqual(encoder.encode('\u0300'), '\xab\xdc')
-        self.assertEqual(encoder.encode('\u00e6'), '')
+        self.assertEqual(encoder.encode('\u0300'), b'\xab\xdc')
+        self.assertEqual(encoder.encode('\u00e6'), b'')
         self.assertRaises(UnicodeEncodeError, encoder.encode, '\u0123')
-        self.assertEqual(encoder.encode('', True), '\xa9\xdc')
+        self.assertEqual(encoder.encode('', True), b'\xa9\xdc')
 
 
 class Test_IncrementalDecoder(unittest.TestCase):
@@ -105,21 +105,21 @@
     def test_dbcs(self):
         # cp949 decoder is simple with only 1 or 2 bytes sequences.
         decoder = codecs.getincrementaldecoder('cp949')()
-        self.assertEqual(decoder.decode('\xc6\xc4\xc0\xcc\xbd'),
+        self.assertEqual(decoder.decode(b'\xc6\xc4\xc0\xcc\xbd'),
                          '\ud30c\uc774')
-        self.assertEqual(decoder.decode('\xe3 \xb8\xb6\xc0\xbb'),
+        self.assertEqual(decoder.decode(b'\xe3 \xb8\xb6\xc0\xbb'),
                          '\uc36c \ub9c8\uc744')
-        self.assertEqual(decoder.decode(''), '')
+        self.assertEqual(decoder.decode(b''), '')
 
     def test_dbcs_keep_buffer(self):
         decoder = codecs.getincrementaldecoder('cp949')()
-        self.assertEqual(decoder.decode('\xc6\xc4\xc0'), '\ud30c')
+        self.assertEqual(decoder.decode(b'\xc6\xc4\xc0'), '\ud30c')
         self.assertRaises(UnicodeDecodeError, decoder.decode, '', True)
-        self.assertEqual(decoder.decode('\xcc'), '\uc774')
+        self.assertEqual(decoder.decode(b'\xcc'), '\uc774')
 
-        self.assertEqual(decoder.decode('\xc6\xc4\xc0'), '\ud30c')
+        self.assertEqual(decoder.decode(b'\xc6\xc4\xc0'), '\ud30c')
         self.assertRaises(UnicodeDecodeError, decoder.decode, '\xcc\xbd', True)
-        self.assertEqual(decoder.decode('\xcc'), '\uc774')
+        self.assertEqual(decoder.decode(b'\xcc'), '\uc774')
 
     def test_iso2022(self):
         decoder = codecs.getincrementaldecoder('iso2022-jp')()
@@ -140,61 +140,61 @@
 class Test_StreamWriter(unittest.TestCase):
     if len('\U00012345') == 2: # UCS2
         def test_gb18030(self):
-            s= StringIO.StringIO()
+            s= io.BytesIO()
             c = codecs.getwriter('gb18030')(s)
             c.write('123')
-            self.assertEqual(s.getvalue(), '123')
+            self.assertEqual(s.getvalue(), b'123')
             c.write('\U00012345')
-            self.assertEqual(s.getvalue(), '123\x907\x959')
+            self.assertEqual(s.getvalue(), b'123\x907\x959')
             c.write('\U00012345'[0])
-            self.assertEqual(s.getvalue(), '123\x907\x959')
+            self.assertEqual(s.getvalue(), b'123\x907\x959')
             c.write('\U00012345'[1] + '\U00012345' + '\uac00\u00ac')
             self.assertEqual(s.getvalue(),
-                    '123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
+                    b'123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
             c.write('\U00012345'[0])
             self.assertEqual(s.getvalue(),
-                    '123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
+                    b'123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
             self.assertRaises(UnicodeError, c.reset)
             self.assertEqual(s.getvalue(),
-                    '123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
+                    b'123\x907\x959\x907\x959\x907\x959\x827\xcf5\x810\x851')
 
         def test_utf_8(self):
-            s= StringIO.StringIO()
+            s= io.BytesIO()
             c = codecs.getwriter('utf-8')(s)
             c.write('123')
-            self.assertEqual(s.getvalue(), '123')
+            self.assertEqual(s.getvalue(), b'123')
             c.write('\U00012345')
-            self.assertEqual(s.getvalue(), '123\xf0\x92\x8d\x85')
+            self.assertEqual(s.getvalue(), b'123\xf0\x92\x8d\x85')
 
             # Python utf-8 codec can't buffer surrogate pairs yet.
             if 0:
                 c.write('\U00012345'[0])
-                self.assertEqual(s.getvalue(), '123\xf0\x92\x8d\x85')
+                self.assertEqual(s.getvalue(), b'123\xf0\x92\x8d\x85')
                 c.write('\U00012345'[1] + '\U00012345' + '\uac00\u00ac')
                 self.assertEqual(s.getvalue(),
-                    '123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
-                    '\xea\xb0\x80\xc2\xac')
+                    b'123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
+                    b'\xea\xb0\x80\xc2\xac')
                 c.write('\U00012345'[0])
                 self.assertEqual(s.getvalue(),
-                    '123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
-                    '\xea\xb0\x80\xc2\xac')
+                    b'123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
+                    b'\xea\xb0\x80\xc2\xac')
                 c.reset()
                 self.assertEqual(s.getvalue(),
-                    '123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
-                    '\xea\xb0\x80\xc2\xac\xed\xa0\x88')
+                    b'123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
+                    b'\xea\xb0\x80\xc2\xac\xed\xa0\x88')
                 c.write('\U00012345'[1])
                 self.assertEqual(s.getvalue(),
-                    '123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
-                    '\xea\xb0\x80\xc2\xac\xed\xa0\x88\xed\xbd\x85')
+                    b'123\xf0\x92\x8d\x85\xf0\x92\x8d\x85\xf0\x92\x8d\x85'
+                    b'\xea\xb0\x80\xc2\xac\xed\xa0\x88\xed\xbd\x85')
 
     else: # UCS4
         pass
 
     def test_streamwriter_strwrite(self):
-        s = StringIO.StringIO()
+        s = io.BytesIO()
         wr = codecs.getwriter('gb18030')(s)
         wr.write('abcd')
-        self.assertEqual(s.getvalue(), 'abcd')
+        self.assertEqual(s.getvalue(), b'abcd')
 
 class Test_ISO2022(unittest.TestCase):
     def test_g2(self):
@@ -203,10 +203,10 @@
         self.assertEqual(iso2022jp2.decode('iso2022-jp-2'), uni)
 
     def test_iso2022_jp_g0(self):
-        self.failIf('\x0e' in '\N{SOFT HYPHEN}'.encode('iso-2022-jp-2'))
+        self.failIf(b'\x0e' in '\N{SOFT HYPHEN}'.encode('iso-2022-jp-2'))
         for encoding in ('iso-2022-jp-2004', 'iso-2022-jp-3'):
             e = '\u3406'.encode(encoding)
-            self.failIf(filter(lambda x: x >= '\x80', e))
+            self.failIf(any(x > 0x80 for x in e))
 
     def test_bug1572832(self):
         if sys.maxunicode >= 0x10000: