diff --git a/Lib/ctypes/test/test_internals.py b/Lib/ctypes/test/test_internals.py
index 520ff87..c6a51a7 100644
--- a/Lib/ctypes/test/test_internals.py
+++ b/Lib/ctypes/test/test_internals.py
@@ -76,11 +76,13 @@
         x = X()
         x.a = s1
         x.b = s2
-        self.failUnlessEqual(x._objects, {"0": bytes(s1), "1": bytes(s2)})
+        self.failUnlessEqual(x._objects, {"0": bytes(s1, "ascii"),
+                                          "1": bytes(s2, "ascii")})
 
         y = Y()
         y.x = x
-        self.failUnlessEqual(y._objects, {"0": {"0": bytes(s1), "1": bytes(s2)}})
+        self.failUnlessEqual(y._objects, {"0": {"0": bytes(s1, "ascii"),
+                                                "1": bytes(s2, "ascii")}})
 ##        x = y.x
 ##        del y
 ##        print x._b_base_._objects
diff --git a/Lib/hmac.py b/Lib/hmac.py
index 7bf3c03..1911689 100644
--- a/Lib/hmac.py
+++ b/Lib/hmac.py
@@ -37,10 +37,7 @@
         if key is _secret_backdoor_key: # cheap
             return
 
-        if not isinstance(key, bytes):
-            if hasattr(key, "__index__"):
-                raise TypeError("key can't be a number")
-            key = bytes(key)
+        assert isinstance(key, bytes), repr(key)
 
         if digestmod is None:
             import hashlib
@@ -71,10 +68,7 @@
     def update(self, msg):
         """Update this hashing object with the string msg.
         """
-        if not isinstance(msg, bytes):
-            if hasattr(msg, "__index__"):
-                raise TypeError("msg can't be a number")
-            msg = bytes(msg)
+        assert isinstance(msg, bytes), repr(msg)
         self.inner.update(msg)
 
     def copy(self):
diff --git a/Lib/mimetools.py b/Lib/mimetools.py
index 45d9d32..0553989 100644
--- a/Lib/mimetools.py
+++ b/Lib/mimetools.py
@@ -158,7 +158,7 @@
         import uu
         return uu.decode(input, output)
     if encoding in ('7bit', '8bit'):
-        return output.write(input.read().decode("Latin-1"))
+        return output.write(input.read())
     if encoding in decodetab:
         pipethrough(input, decodetab[encoding], output)
     else:
diff --git a/Lib/pickle.py b/Lib/pickle.py
index 6901a64..9127f14 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -248,7 +248,7 @@
             else:
                 return LONG_BINPUT + pack("<i", i)
 
-        return PUT + bytes(repr(i)) + b'\n'
+        return PUT + repr(i).encode("ascii") + b'\n'
 
     # Return a GET (BINGET, LONG_BINGET) opcode string, with argument i.
     def get(self, i, pack=struct.pack):
@@ -258,7 +258,7 @@
             else:
                 return LONG_BINGET + pack("<i", i)
 
-        return GET + bytes(repr(i)) + b'\n'
+        return GET + repr(i).encode("ascii") + b'\n'
 
     def save(self, obj):
         # Check for persistent id (defined by a subclass)
@@ -334,7 +334,7 @@
             self.save(pid)
             self.write(BINPERSID)
         else:
-            self.write(PERSID + bytes(str(pid)) + b'\n')
+            self.write(PERSID + str(pid).encode("ascii") + b'\n')
 
     def save_reduce(self, func, args, state=None,
                     listitems=None, dictitems=None, obj=None):
@@ -449,7 +449,7 @@
                 self.write(BININT + pack("<i", obj))
                 return
         # Text pickle, or int too big to fit in signed 4-byte format.
-        self.write(INT + bytes(repr(obj)) + b'\n')
+        self.write(INT + repr(obj).encode("ascii") + b'\n')
     # XXX save_int is merged into save_long
     # dispatch[int] = save_int
 
@@ -481,14 +481,14 @@
             else:
                 self.write(LONG4 + pack("<i", n) + encoded)
             return
-        self.write(LONG + bytes(repr(obj)) + b'\n')
+        self.write(LONG + repr(obj).encode("ascii") + b'\n')
     dispatch[int] = save_long
 
     def save_float(self, obj, pack=struct.pack):
         if self.bin:
             self.write(BINFLOAT + pack('>d', obj))
         else:
-            self.write(FLOAT + bytes(repr(obj)) + b'\n')
+            self.write(FLOAT + repr(obj).encode("ascii") + b'\n')
     dispatch[float] = save_float
 
     def save_string(self, obj, pack=struct.pack):
@@ -500,7 +500,7 @@
                 self.write(BINSTRING + pack("<i", n) + bytes(obj))
         else:
             # Strip leading 's' due to repr() of str8() returning s'...'
-            self.write(STRING + bytes(repr(obj).lstrip("s")) + b'\n')
+            self.write(STRING + repr(obj).lstrip("s").encode("ascii") + b'\n')
         self.memoize(obj)
     dispatch[str8] = save_string
 
@@ -710,7 +710,8 @@
                     write(EXT4 + pack("<i", code))
                 return
 
-        write(GLOBAL + bytes(module) + b'\n' + bytes(name) + b'\n')
+        write(GLOBAL + bytes(module, "utf-8") + b'\n' +
+              bytes(name, "utf-8") + b'\n')
         self.memoize(obj)
 
     dispatch[FunctionType] = save_global
diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index 0ad1f48..bc360b8 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -461,18 +461,19 @@
         self.assertRaises(self.error, self.loads, b'garyp')
 
     def test_insecure_strings(self):
-        insecure = ["abc", "2 + 2", # not quoted
-                    #"'abc' + 'def'", # not a single quoted string
-                    "'abc", # quote is not closed
-                    "'abc\"", # open quote and close quote don't match
-                    "'abc'   ?", # junk after close quote
-                    "'\\'", # trailing backslash
+        # XXX Some of these tests are temporarily disabled
+        insecure = [b"abc", b"2 + 2", # not quoted
+                    ## b"'abc' + 'def'", # not a single quoted string
+                    b"'abc", # quote is not closed
+                    b"'abc\"", # open quote and close quote don't match
+                    b"'abc'   ?", # junk after close quote
+                    b"'\\'", # trailing backslash
                     # some tests of the quoting rules
-                    #"'abc\"\''",
-                    #"'\\\\a\'\'\'\\\'\\\\\''",
+                    ## b"'abc\"\''",
+                    ## b"'\\\\a\'\'\'\\\'\\\\\''",
                     ]
-        for s in insecure:
-            buf = b"S" + bytes(s) + b"\012p0\012."
+        for b in insecure:
+            buf = b"S" + b + b"\012p0\012."
             self.assertRaises(ValueError, self.loads, buf)
 
     def test_unicode(self):
@@ -496,12 +497,12 @@
 
     def test_maxint64(self):
         maxint64 = (1 << 63) - 1
-        data = b'I' + bytes(str(maxint64)) + b'\n.'
+        data = b'I' + str(maxint64).encode("ascii") + b'\n.'
         got = self.loads(data)
         self.assertEqual(got, maxint64)
 
         # Try too with a bogus literal.
-        data = b'I' + bytes(str(maxint64)) + b'JUNK\n.'
+        data = b'I' + str(maxint64).encode("ascii") + b'JUNK\n.'
         self.assertRaises(ValueError, self.loads, data)
 
     def test_long(self):
@@ -699,7 +700,7 @@
 
             # Dump using protocol 1 for comparison.
             s1 = self.dumps(x, 1)
-            self.assert_(bytes(__name__) in s1)
+            self.assert_(__name__.encode("utf-8") in s1)
             self.assert_(b"MyList" in s1)
             self.assertEqual(opcode_in_pickle(opcode, s1), False)
 
@@ -709,7 +710,7 @@
 
             # Dump using protocol 2 for test.
             s2 = self.dumps(x, 2)
-            self.assert_(bytes(__name__) not in s2)
+            self.assert_(__name__.encode("utf-8") not in s2)
             self.assert_(b"MyList" not in s2)
             self.assertEqual(opcode_in_pickle(opcode, s2), True, repr(s2))
 
diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index fe159b6..56275d6 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -498,10 +498,12 @@
         EQ("bobobXbobob", "bobobobXbobobob", "replace", "bobob", "bob")
         EQ("BOBOBOB", "BOBOBOB", "replace", "bob", "bobby")
 
-        ba = buffer('a')
-        bb = buffer('b')
-        EQ("bbc", "abc", "replace", ba, bb)
-        EQ("aac", "abc", "replace", bb, ba)
+        # XXX Commented out. Is there any reason to support buffer objects
+        # as arguments for str.replace()?  GvR
+##         ba = buffer('a')
+##         bb = buffer('b')
+##         EQ("bbc", "abc", "replace", ba, bb)
+##         EQ("aac", "abc", "replace", bb, ba)
 
         #
         self.checkequal('one@two!three!', 'one!two!three!', 'replace', '!', '@', 1)
diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py
index 8299ca1..116ce54 100644
--- a/Lib/test/test_complex.py
+++ b/Lib/test/test_complex.py
@@ -322,7 +322,7 @@
             print(a, b, file=fo)
             fo.close()
             fo = open(test_support.TESTFN, "rb")
-            self.assertEqual(fo.read(), bytes("%s %s\n" % (a, b)))
+            self.assertEqual(fo.read(), ("%s %s\n" % (a, b)).encode("ascii"))
         finally:
             if (fo is not None) and (not fo.closed):
                 fo.close()
diff --git a/Lib/test/test_datetime.py b/Lib/test/test_datetime.py
index b26c92e..dce9fc3 100644
--- a/Lib/test/test_datetime.py
+++ b/Lib/test/test_datetime.py
@@ -1085,7 +1085,7 @@
             # This shouldn't blow up because of the month byte alone.  If
             # the implementation changes to do more-careful checking, it may
             # blow up because other fields are insane.
-            self.theclass(bytes(base[:2] + chr(ord_byte) + base[3:]))
+            self.theclass(bytes(base[:2] + chr(ord_byte) + base[3:], "ascii"))
 
 #############################################################################
 # datetime tests
diff --git a/Lib/test/test_gettext.py b/Lib/test/test_gettext.py
index 676d2fe..a32fa27 100644
--- a/Lib/test/test_gettext.py
+++ b/Lib/test/test_gettext.py
@@ -13,7 +13,7 @@
 #    has no sense, it would have if we were testing a parser (i.e. pygettext)
 #  - Tests should have only one assert.
 
-GNU_MO_DATA = '''\
+GNU_MO_DATA = b'''\
 3hIElQAAAAAGAAAAHAAAAEwAAAALAAAAfAAAAAAAAACoAAAAFQAAAKkAAAAjAAAAvwAAAKEAAADj
 AAAABwAAAIUBAAALAAAAjQEAAEUBAACZAQAAFgAAAN8CAAAeAAAA9gIAAKEAAAAVAwAABQAAALcD
 AAAJAAAAvQMAAAEAAAADAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAABQAAAAYAAAACAAAAAFJh
@@ -33,7 +33,7 @@
 ciBUQUgKdHJnZ3JrZyB6cmZmbnRyIHBuZ255YnQgeXZvZW5lbC4AYmFjb24Ad2luayB3aW5rAA==
 '''
 
-UMO_DATA = '''\
+UMO_DATA = b'''\
 3hIElQAAAAACAAAAHAAAACwAAAAFAAAAPAAAAAAAAABQAAAABAAAAFEAAAAPAQAAVgAAAAQAAABm
 AQAAAQAAAAIAAAAAAAAAAAAAAAAAAAAAYWLDngBQcm9qZWN0LUlkLVZlcnNpb246IDIuMApQTy1S
 ZXZpc2lvbi1EYXRlOiAyMDAzLTA0LTExIDEyOjQyLTA0MDAKTGFzdC1UcmFuc2xhdG9yOiBCYXJy
@@ -43,7 +43,7 @@
 ZC1CeTogbWFudWFsbHkKAMKkeXoA
 '''
 
-MMO_DATA = '''\
+MMO_DATA = b'''\
 3hIElQAAAAABAAAAHAAAACQAAAADAAAALAAAAAAAAAA4AAAAeAEAADkAAAABAAAAAAAAAAAAAAAA
 UHJvamVjdC1JZC1WZXJzaW9uOiBObyBQcm9qZWN0IDAuMApQT1QtQ3JlYXRpb24tRGF0ZTogV2Vk
 IERlYyAxMSAwNzo0NDoxNSAyMDAyClBPLVJldmlzaW9uLURhdGU6IDIwMDItMDgtMTQgMDE6MTg6
diff --git a/Lib/test/test_hmac.py b/Lib/test/test_hmac.py
index d44197e..c654e87 100644
--- a/Lib/test/test_hmac.py
+++ b/Lib/test/test_hmac.py
@@ -24,21 +24,21 @@
                 b"\xdd" * 50,
                 "56be34521d144c88dbb8c733f0e8b3f6")
 
-        md5test("".join([chr(i) for i in range(1, 26)]),
+        md5test(bytes(range(1, 26)),
                 b"\xcd" * 50,
                 "697eaf0aca3a3aea3a75164746ffaa79")
 
-        md5test(chr(0x0C) * 16,
-                "Test With Truncation",
+        md5test(b"\x0C" * 16,
+                b"Test With Truncation",
                 "56461ef2342edc00f9bab995690efd4c")
 
         md5test(b"\xaa" * 80,
-                "Test Using Larger Than Block-Size Key - Hash Key First",
+                b"Test Using Larger Than Block-Size Key - Hash Key First",
                 "6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd")
 
         md5test(b"\xaa" * 80,
-                ("Test Using Larger Than Block-Size Key "
-                 "and Larger Than One Block-Size Data"),
+                (b"Test Using Larger Than Block-Size Key "
+                 b"and Larger Than One Block-Size Data"),
                 "6f630fad67cda0ee1fb1f562db3aa53e")
 
     def test_sha_vectors(self):
@@ -62,8 +62,8 @@
                 b"\xCD" * 50,
                 "4c9007f4026250c6bc8414f9bf50c86c2d7235da")
 
-        shatest(chr(0x0C) * 20,
-                "Test With Truncation",
+        shatest(b"\x0C" * 20,
+                b"Test With Truncation",
                 "4c1a03424b55e07fe7f27be1d58bb9324a9a5a04")
 
         shatest(b"\xAA" * 80,
@@ -82,14 +82,14 @@
         # Standard constructor call.
         failed = 0
         try:
-            h = hmac.HMAC("key")
+            h = hmac.HMAC(b"key")
         except:
             self.fail("Standard constructor call raised exception.")
 
     def test_withtext(self):
         # Constructor call with text.
         try:
-            h = hmac.HMAC("key", "hash this!")
+            h = hmac.HMAC(b"key", b"hash this!")
         except:
             self.fail("Constructor call with text argument raised exception.")
 
@@ -97,7 +97,7 @@
         # Constructor call with text and digest module.
         from hashlib import sha1
         try:
-            h = hmac.HMAC("key", "", sha1)
+            h = hmac.HMAC(b"key", b"", sha1)
         except:
             self.fail("Constructor call with hashlib.sha1 raised exception.")
 
@@ -107,15 +107,15 @@
         # Testing if HMAC defaults to MD5 algorithm.
         # NOTE: this whitebox test depends on the hmac class internals
         import hashlib
-        h = hmac.HMAC("key")
+        h = hmac.HMAC(b"key")
         self.assertEqual(h.digest_cons, hashlib.md5)
 
     def test_exercise_all_methods(self):
         # Exercising all methods once.
         # This must not raise any exceptions
         try:
-            h = hmac.HMAC("my secret key")
-            h.update("compute the hash of this text!")
+            h = hmac.HMAC(b"my secret key")
+            h.update(b"compute the hash of this text!")
             dig = h.digest()
             dig = h.hexdigest()
             h2 = h.copy()
@@ -126,7 +126,7 @@
 
     def test_attributes(self):
         # Testing if attributes are of same type.
-        h1 = hmac.HMAC("key")
+        h1 = hmac.HMAC(b"key")
         h2 = h1.copy()
         self.failUnless(h1.digest_cons == h2.digest_cons,
             "digest constructors don't match.")
@@ -137,7 +137,7 @@
 
     def test_realcopy(self):
         # Testing if the copy method created a real copy.
-        h1 = hmac.HMAC("key")
+        h1 = hmac.HMAC(b"key")
         h2 = h1.copy()
         # Using id() in case somebody has overridden __cmp__.
         self.failUnless(id(h1) != id(h2), "No real copy of the HMAC instance.")
@@ -148,8 +148,8 @@
 
     def test_equality(self):
         # Testing if the copy has the same digests.
-        h1 = hmac.HMAC("key")
-        h1.update("some random text")
+        h1 = hmac.HMAC(b"key")
+        h1.update(b"some random text")
         h2 = h1.copy()
         self.assertEqual(h1.digest(), h2.digest(),
             "Digest of copy doesn't match original digest.")
diff --git a/Lib/test/test_httplib.py b/Lib/test/test_httplib.py
index 18fde4a..2d61c46 100644
--- a/Lib/test/test_httplib.py
+++ b/Lib/test/test_httplib.py
@@ -10,7 +10,7 @@
 class FakeSocket:
     def __init__(self, text, fileclass=io.BytesIO):
         if isinstance(text, str):
-            text = bytes(text)
+            text = text.encode("ascii")
         self.text = text
         self.fileclass = fileclass
         self.data = b''
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index f8a4938..656711f 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -305,7 +305,9 @@
 
 
 class BytesIOTest(MemorySeekTestMixin, unittest.TestCase):
-    buftype = bytes
+    @staticmethod
+    def buftype(s):
+        return s.encode("utf-8")
     ioclass = io.BytesIO
     EOF = b""
 
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index c925f68..ad01d6a 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -660,7 +660,7 @@
         try:
             f = tempfile.SpooledTemporaryFile(max_size=10, dir=dir)
             self.failIf(f._rolled)
-            f.write('blat ' * 5)
+            f.write(b'blat ' * 5)
             self.failUnless(f._rolled)
             filename = f.name
             f.close()
@@ -675,7 +675,7 @@
         self.failIf(f._rolled)
         for i in range(5):
             f.seek(0, 0)
-            f.write('x' * 20)
+            f.write(b'x' * 20)
         self.failIf(f._rolled)
 
     def test_write_sequential(self):
@@ -683,11 +683,11 @@
         # over afterward
         f = self.do_create(max_size=30)
         self.failIf(f._rolled)
-        f.write('x' * 20)
+        f.write(b'x' * 20)
         self.failIf(f._rolled)
-        f.write('x' * 10)
+        f.write(b'x' * 10)
         self.failIf(f._rolled)
-        f.write('x')
+        f.write(b'x')
         self.failUnless(f._rolled)
 
     def test_sparse(self):
@@ -697,7 +697,7 @@
         self.failIf(f._rolled)
         f.seek(100, 0)
         self.failIf(f._rolled)
-        f.write('x')
+        f.write(b'x')
         self.failUnless(f._rolled)
 
     def test_fileno(self):
@@ -710,7 +710,7 @@
     def test_multiple_close(self):
         # A SpooledTemporaryFile can be closed many times without error
         f = tempfile.SpooledTemporaryFile()
-        f.write('abc\n')
+        f.write(b'abc\n')
         f.close()
         try:
             f.close()
@@ -727,8 +727,8 @@
         write = f.write
         seek = f.seek
 
-        write("a" * 35)
-        write("b" * 35)
+        write(b"a" * 35)
+        write(b"b" * 35)
         seek(0, 0)
         self.assertEqual(read(70), b'a'*35 + b'b'*35)
 
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index c39ec09..ef29b2f 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -701,7 +701,7 @@
         if not sys.platform.startswith('java'):
             self.assertEqual(
                 str(
-                    buffer('character buffers are decoded to unicode'),
+                    buffer(b'character buffers are decoded to unicode'),
                     'utf-8',
                     'strict'
                 ),
@@ -791,7 +791,7 @@
         self.assertEqual(str(b'Andr\202 x', 'ascii', 'replace'), 'Andr\uFFFD x')
 
         # Error handling (unknown character names)
-        self.assertEqual("\\N{foo}xx".decode("unicode-escape", "ignore"), "xx")
+        self.assertEqual(b"\\N{foo}xx".decode("unicode-escape", "ignore"), "xx")
 
         # Error handling (truncated escape sequence)
         self.assertRaises(UnicodeError, "\\".decode, "unicode-escape")
diff --git a/Lib/uu.py b/Lib/uu.py
index 084d9f3..18a9f79 100755
--- a/Lib/uu.py
+++ b/Lib/uu.py
@@ -72,12 +72,12 @@
     #
     # Write the data
     #
-    out_file.write('begin %o %s\n' % ((mode & 0o777),name))
+    out_file.write(('begin %o %s\n' % ((mode & 0o777), name)).encode("ascii"))
     data = in_file.read(45)
     while len(data) > 0:
-        out_file.write(str(binascii.b2a_uu(data), "ascii"))
+        out_file.write(binascii.b2a_uu(data))
         data = in_file.read(45)
-    out_file.write(' \nend\n')
+    out_file.write(b' \nend\n')
 
 
 def decode(in_file, out_file=None, mode=None, quiet=0):