For PEP3137: Adds missing methods to the mutable PyBytes object (soon
to be called a buffer).  Shares code with stringobject when possible.
Adds unit tests with common code that should be usable to test the PEPs
mutable buffer() and immutable bytes() types.

 http://bugs.python.org/issue1261
diff --git a/Lib/test/buffer_tests.py b/Lib/test/buffer_tests.py
new file mode 100644
index 0000000..01ac3c5
--- /dev/null
+++ b/Lib/test/buffer_tests.py
@@ -0,0 +1,206 @@
+# Tests that work for both str8 (bytes) and bytes (buffer) objects.
+# See PEP 3137.
+
+import struct
+import sys
+
+class MixinBytesBufferCommonTests(object):
+    """Tests that work for both str8 (bytes) and bytes (buffer) objects.
+    See PEP 3137.
+    """
+
+    def marshal(self, x):
+        """Convert x into the appropriate type for these tests."""
+        raise RuntimeError('test class must provide a marshal method')
+
+    def test_islower(self):
+        self.assertFalse(self.marshal(b'').islower())
+        self.assert_(self.marshal(b'a').islower())
+        self.assertFalse(self.marshal(b'A').islower())
+        self.assertFalse(self.marshal(b'\n').islower())
+        self.assert_(self.marshal(b'abc').islower())
+        self.assertFalse(self.marshal(b'aBc').islower())
+        self.assert_(self.marshal(b'abc\n').islower())
+        self.assertRaises(TypeError, self.marshal(b'abc').islower, 42)
+
+    def test_isupper(self):
+        self.assertFalse(self.marshal(b'').isupper())
+        self.assertFalse(self.marshal(b'a').isupper())
+        self.assert_(self.marshal(b'A').isupper())
+        self.assertFalse(self.marshal(b'\n').isupper())
+        self.assert_(self.marshal(b'ABC').isupper())
+        self.assertFalse(self.marshal(b'AbC').isupper())
+        self.assert_(self.marshal(b'ABC\n').isupper())
+        self.assertRaises(TypeError, self.marshal(b'abc').isupper, 42)
+
+    def test_istitle(self):
+        self.assertFalse(self.marshal(b'').istitle())
+        self.assertFalse(self.marshal(b'a').istitle())
+        self.assert_(self.marshal(b'A').istitle())
+        self.assertFalse(self.marshal(b'\n').istitle())
+        self.assert_(self.marshal(b'A Titlecased Line').istitle())
+        self.assert_(self.marshal(b'A\nTitlecased Line').istitle())
+        self.assert_(self.marshal(b'A Titlecased, Line').istitle())
+        self.assertFalse(self.marshal(b'Not a capitalized String').istitle())
+        self.assertFalse(self.marshal(b'Not\ta Titlecase String').istitle())
+        self.assertFalse(self.marshal(b'Not--a Titlecase String').istitle())
+        self.assertFalse(self.marshal(b'NOT').istitle())
+        self.assertRaises(TypeError, self.marshal(b'abc').istitle, 42)
+
+    def test_isspace(self):
+        self.assertFalse(self.marshal(b'').isspace())
+        self.assertFalse(self.marshal(b'a').isspace())
+        self.assert_(self.marshal(b' ').isspace())
+        self.assert_(self.marshal(b'\t').isspace())
+        self.assert_(self.marshal(b'\r').isspace())
+        self.assert_(self.marshal(b'\n').isspace())
+        self.assert_(self.marshal(b' \t\r\n').isspace())
+        self.assertFalse(self.marshal(b' \t\r\na').isspace())
+        self.assertRaises(TypeError, self.marshal(b'abc').isspace, 42)
+
+    def test_isalpha(self):
+        self.assertFalse(self.marshal(b'').isalpha())
+        self.assert_(self.marshal(b'a').isalpha())
+        self.assert_(self.marshal(b'A').isalpha())
+        self.assertFalse(self.marshal(b'\n').isalpha())
+        self.assert_(self.marshal(b'abc').isalpha())
+        self.assertFalse(self.marshal(b'aBc123').isalpha())
+        self.assertFalse(self.marshal(b'abc\n').isalpha())
+        self.assertRaises(TypeError, self.marshal(b'abc').isalpha, 42)
+
+    def test_isalnum(self):
+        self.assertFalse(self.marshal(b'').isalnum())
+        self.assert_(self.marshal(b'a').isalnum())
+        self.assert_(self.marshal(b'A').isalnum())
+        self.assertFalse(self.marshal(b'\n').isalnum())
+        self.assert_(self.marshal(b'123abc456').isalnum())
+        self.assert_(self.marshal(b'a1b3c').isalnum())
+        self.assertFalse(self.marshal(b'aBc000 ').isalnum())
+        self.assertFalse(self.marshal(b'abc\n').isalnum())
+        self.assertRaises(TypeError, self.marshal(b'abc').isalnum, 42)
+
+    def test_isdigit(self):
+        self.assertFalse(self.marshal(b'').isdigit())
+        self.assertFalse(self.marshal(b'a').isdigit())
+        self.assert_(self.marshal(b'0').isdigit())
+        self.assert_(self.marshal(b'0123456789').isdigit())
+        self.assertFalse(self.marshal(b'0123456789a').isdigit())
+
+        self.assertRaises(TypeError, self.marshal(b'abc').isdigit, 42)
+
+    def test_lower(self):
+        self.assertEqual(b'hello', self.marshal(b'HeLLo').lower())
+        self.assertEqual(b'hello', self.marshal(b'hello').lower())
+        self.assertRaises(TypeError, self.marshal(b'hello').lower, 42)
+
+    def test_upper(self):
+        self.assertEqual(b'HELLO', self.marshal(b'HeLLo').upper())
+        self.assertEqual(b'HELLO', self.marshal(b'HELLO').upper())
+        self.assertRaises(TypeError, self.marshal(b'hello').upper, 42)
+
+    def test_capitalize(self):
+        self.assertEqual(b' hello ', self.marshal(b' hello ').capitalize())
+        self.assertEqual(b'Hello ', self.marshal(b'Hello ').capitalize())
+        self.assertEqual(b'Hello ', self.marshal(b'hello ').capitalize())
+        self.assertEqual(b'Aaaa', self.marshal(b'aaaa').capitalize())
+        self.assertEqual(b'Aaaa', self.marshal(b'AaAa').capitalize())
+
+        self.assertRaises(TypeError, self.marshal(b'hello').capitalize, 42)
+
+    def test_ljust(self):
+        self.assertEqual(b'abc       ', self.marshal(b'abc').ljust(10))
+        self.assertEqual(b'abc   ', self.marshal(b'abc').ljust(6))
+        self.assertEqual(b'abc', self.marshal(b'abc').ljust(3))
+        self.assertEqual(b'abc', self.marshal(b'abc').ljust(2))
+        self.assertEqual(b'abc*******', self.marshal(b'abc').ljust(10, '*'))
+        self.assertRaises(TypeError, self.marshal(b'abc').ljust)
+
+    def test_rjust(self):
+        self.assertEqual(b'       abc', self.marshal(b'abc').rjust(10))
+        self.assertEqual(b'   abc', self.marshal(b'abc').rjust(6))
+        self.assertEqual(b'abc', self.marshal(b'abc').rjust(3))
+        self.assertEqual(b'abc', self.marshal(b'abc').rjust(2))
+        self.assertEqual(b'*******abc', self.marshal(b'abc').rjust(10, '*'))
+        self.assertRaises(TypeError, self.marshal(b'abc').rjust)
+
+    def test_center(self):
+        self.assertEqual(b'   abc    ', self.marshal(b'abc').center(10))
+        self.assertEqual(b' abc  ', self.marshal(b'abc').center(6))
+        self.assertEqual(b'abc', self.marshal(b'abc').center(3))
+        self.assertEqual(b'abc', self.marshal(b'abc').center(2))
+        self.assertEqual(b'***abc****', self.marshal(b'abc').center(10, '*'))
+        self.assertRaises(TypeError, self.marshal(b'abc').center)
+
+    def test_swapcase(self):
+        self.assertEqual(b'hEllO CoMPuTErS',
+            self.marshal(b'HeLLo cOmpUteRs').swapcase())
+
+        self.assertRaises(TypeError, self.marshal(b'hello').swapcase, 42)
+
+    def test_zfill(self):
+        self.assertEqual(b'123', self.marshal(b'123').zfill(2))
+        self.assertEqual(b'123', self.marshal(b'123').zfill(3))
+        self.assertEqual(b'0123', self.marshal(b'123').zfill(4))
+        self.assertEqual(b'+123', self.marshal(b'+123').zfill(3))
+        self.assertEqual(b'+123', self.marshal(b'+123').zfill(4))
+        self.assertEqual(b'+0123', self.marshal(b'+123').zfill(5))
+        self.assertEqual(b'-123', self.marshal(b'-123').zfill(3))
+        self.assertEqual(b'-123', self.marshal(b'-123').zfill(4))
+        self.assertEqual(b'-0123', self.marshal(b'-123').zfill(5))
+        self.assertEqual(b'000', self.marshal(b'').zfill(3))
+        self.assertEqual(b'34', self.marshal(b'34').zfill(1))
+        self.assertEqual(b'0034', self.marshal(b'34').zfill(4))
+
+        self.assertRaises(TypeError, self.marshal(b'123').zfill)
+
+    def test_expandtabs(self):
+        self.assertEqual(b'abc\rab      def\ng       hi',
+                         self.marshal(b'abc\rab\tdef\ng\thi').expandtabs())
+        self.assertEqual(b'abc\rab      def\ng       hi',
+                         self.marshal(b'abc\rab\tdef\ng\thi').expandtabs(8))
+        self.assertEqual(b'abc\rab  def\ng   hi',
+                         self.marshal(b'abc\rab\tdef\ng\thi').expandtabs(4))
+        self.assertEqual(b'abc\r\nab  def\ng   hi',
+                         self.marshal(b'abc\r\nab\tdef\ng\thi').expandtabs(4))
+        self.assertEqual(b'abc\rab      def\ng       hi',
+                         self.marshal(b'abc\rab\tdef\ng\thi').expandtabs())
+        self.assertEqual(b'abc\rab      def\ng       hi',
+                         self.marshal(b'abc\rab\tdef\ng\thi').expandtabs(8))
+        self.assertEqual(b'abc\r\nab\r\ndef\ng\r\nhi',
+            self.marshal(b'abc\r\nab\r\ndef\ng\r\nhi').expandtabs(4))
+        self.assertEqual(b'  a\n b', self.marshal(b' \ta\n\tb').expandtabs(1))
+
+        self.assertRaises(TypeError, self.marshal(b'hello').expandtabs, 42, 42)
+        # This test is only valid when sizeof(int) == sizeof(void*) == 4.
+        if sys.maxint < (1 << 32) and struct.calcsize('P') == 4:
+            self.assertRaises(OverflowError,
+                              self.marshal(b'\ta\n\tb').expandtabs, sys.maxint)
+
+    def test_title(self):
+        self.assertEqual(b' Hello ', self.marshal(b' hello ').title())
+        self.assertEqual(b'Hello ', self.marshal(b'hello ').title())
+        self.assertEqual(b'Hello ', self.marshal(b'Hello ').title())
+        self.assertEqual(b'Format This As Title String',
+                         self.marshal(b'fOrMaT thIs aS titLe String').title())
+        self.assertEqual(b'Format,This-As*Title;String',
+                         self.marshal(b'fOrMaT,thIs-aS*titLe;String').title())
+        self.assertEqual(b'Getint', self.marshal(b'getInt').title())
+        self.assertRaises(TypeError, self.marshal(b'hello').title, 42)
+
+    def test_splitlines(self):
+        self.assertEqual([b'abc', b'def', b'', b'ghi'],
+                         self.marshal(b'abc\ndef\n\rghi').splitlines())
+        self.assertEqual([b'abc', b'def', b'', b'ghi'],
+                         self.marshal(b'abc\ndef\n\r\nghi').splitlines())
+        self.assertEqual([b'abc', b'def', b'ghi'],
+                         self.marshal(b'abc\ndef\r\nghi').splitlines())
+        self.assertEqual([b'abc', b'def', b'ghi'],
+                         self.marshal(b'abc\ndef\r\nghi\n').splitlines())
+        self.assertEqual([b'abc', b'def', b'ghi', b''],
+                         self.marshal(b'abc\ndef\r\nghi\n\r').splitlines())
+        self.assertEqual([b'', b'abc', b'def', b'ghi', b''],
+                         self.marshal(b'\nabc\ndef\r\nghi\n\r').splitlines())
+        self.assertEqual([b'\n', b'abc\n', b'def\r\n', b'ghi\n', b'\r'],
+                         self.marshal(b'\nabc\ndef\r\nghi\n\r').splitlines(1))
+
+        self.assertRaises(TypeError, self.marshal(b'abc').splitlines, 42, 42)
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index c51a320..391a660 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -8,6 +8,7 @@
 import unittest
 import test.test_support
 import test.string_tests
+import test.buffer_tests
 
 
 class BytesTest(unittest.TestCase):
@@ -454,17 +455,18 @@
     def test_fromhex(self):
         self.assertRaises(TypeError, bytes.fromhex)
         self.assertRaises(TypeError, bytes.fromhex, 1)
-        self.assertEquals(bytes.fromhex(''), bytes())
+        self.assertEquals(bytes.fromhex(b''), bytes())
         b = bytes([0x1a, 0x2b, 0x30])
-        self.assertEquals(bytes.fromhex('1a2B30'), b)
-        self.assertEquals(bytes.fromhex('  1A 2B  30   '), b)
+        self.assertEquals(bytes.fromhex(b'1a2B30'), b)
+        self.assertEquals(bytes.fromhex(b'  1A 2B  30   '), b)
         self.assertEquals(bytes.fromhex(memoryview(b'')), bytes())
         self.assertEquals(bytes.fromhex(memoryview(b'0000')), bytes([0, 0]))
-        self.assertRaises(ValueError, bytes.fromhex, 'a')
-        self.assertRaises(ValueError, bytes.fromhex, 'rt')
-        self.assertRaises(ValueError, bytes.fromhex, '1a b cd')
-        self.assertRaises(ValueError, bytes.fromhex, '\x00')
-        self.assertRaises(ValueError, bytes.fromhex, '12   \x00   34')
+        self.assertRaises(TypeError, bytes.fromhex, '1B')
+        self.assertRaises(ValueError, bytes.fromhex, b'a')
+        self.assertRaises(ValueError, bytes.fromhex, b'rt')
+        self.assertRaises(ValueError, bytes.fromhex, b'1a b cd')
+        self.assertRaises(ValueError, bytes.fromhex, b'\x00')
+        self.assertRaises(ValueError, bytes.fromhex, b'12   \x00   34')
 
     def test_join(self):
         self.assertEqual(b"".join([]), bytes())
@@ -504,11 +506,12 @@
         self.assertEqual(b, b'heo')
         self.assertRaises(ValueError, lambda: b.remove(ord('l')))
         self.assertRaises(ValueError, lambda: b.remove(400))
-        self.assertRaises(ValueError, lambda: b.remove('e'))
+        self.assertRaises(TypeError, lambda: b.remove('e'))
         # remove first and last
         b.remove(ord('o'))
         b.remove(ord('h'))
         self.assertEqual(b, b'e')
+        self.assertRaises(TypeError, lambda: b.remove(b'e'))
 
     def test_pop(self):
         b = b'world'
@@ -542,6 +545,7 @@
         b = bytes()
         b.append(ord('A'))
         self.assertEqual(len(b), 1)
+        self.assertRaises(TypeError, lambda: b.append(b'o'))
 
     def test_insert(self):
         b = b'msssspp'
@@ -550,6 +554,7 @@
         b.insert(-2, ord('i'))
         b.insert(1000, ord('i'))
         self.assertEqual(b, b'mississippi')
+        self.assertRaises(TypeError, lambda: b.insert(0, b'1'))
 
     def test_startswith(self):
         b = b'hello'
@@ -734,6 +739,29 @@
     # Unfortunately they are all bundled with tests that
     # are not appropriate for bytes
 
+    # I've started porting some of those into buffer_tests.py, we should port
+    # the rest that make sense (the code can be cleaned up to use modern
+    # unittest methods at the same time).
+
+class BufferPEP3137Test(unittest.TestCase,
+                       test.buffer_tests.MixinBytesBufferCommonTests):
+    def marshal(self, x):
+        return bytes(x)
+        # TODO this should become:
+        #return buffer(x)
+        # once the bytes -> buffer and str8 -> bytes rename happens
+
+    def test_returns_new_copy(self):
+        val = self.marshal(b'1234')
+        # On immutable types these MAY return a reference to themselves
+        # but on mutable types like buffer they MUST return a new copy.
+        for methname in ('zfill', 'rjust', 'ljust', 'center'):
+            method = getattr(val, methname)
+            newval = method(3)
+            self.assertEqual(val, newval)
+            self.assertTrue(val is not newval,
+                            methname+' returned self on a mutable object')
+
 
 class BytesAsStringTest(test.string_tests.BaseTest):
     type2test = bytes
@@ -759,7 +787,7 @@
 def test_main():
     test.test_support.run_unittest(BytesTest)
     test.test_support.run_unittest(BytesAsStringTest)
-
+    test.test_support.run_unittest(BufferPEP3137Test)
 
 if __name__ == "__main__":
     ##test_main()