diff -r 1b9d8be8b07e Lib/test/test_email/test_email.py
--- a/Lib/test/test_email/test_email.py	Thu Nov 14 23:50:51 2013 +0200
+++ b/Lib/test/test_email/test_email.py	Fri Nov 15 08:49:02 2013 +0200
@@ -366,11 +366,10 @@
         self.assertEqual(msg.get_param('bar'), 'baz"foobar"baz')
 
     def test_field_containment(self):
-        unless = self.assertTrue
         msg = email.message_from_string('Header: exists')
-        unless('header' in msg)
-        unless('Header' in msg)
-        unless('HEADER' in msg)
+        self.assertIn('header', msg)
+        self.assertIn('Header', msg)
+        self.assertIn('HEADER', msg)
         self.assertFalse('headerx' in msg)
 
     def test_set_param(self):
@@ -1427,7 +1426,6 @@
 
     def test_add_header(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         self._au.add_header('Content-Disposition', 'attachment',
                             filename='audiotest.au')
         eq(self._au['content-disposition'],
@@ -1438,12 +1436,12 @@
            'audiotest.au')
         missing = []
         eq(self._au.get_param('attachment', header='content-disposition'), '')
-        unless(self._au.get_param('foo', failobj=missing,
-                                  header='content-disposition') is missing)
+        self.assertIs(self._au.get_param('foo', failobj=missing,
+                                         header='content-disposition'), missing)
         # Try some missing stuff
-        unless(self._au.get_param('foobar', missing) is missing)
-        unless(self._au.get_param('attachment', missing,
-                                  header='foobar') is missing)
+        self.assertIs(self._au.get_param('foobar', missing), missing)
+        self.assertIs(self._au.get_param('attachment', missing,
+                                         header='foobar'), missing)
 
 
 
@@ -1468,7 +1466,6 @@
 
     def test_add_header(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         self._im.add_header('Content-Disposition', 'attachment',
                             filename='dingusfish.gif')
         eq(self._im['content-disposition'],
@@ -1479,12 +1476,12 @@
            'dingusfish.gif')
         missing = []
         eq(self._im.get_param('attachment', header='content-disposition'), '')
-        unless(self._im.get_param('foo', failobj=missing,
-                                  header='content-disposition') is missing)
+        self.assertIs(self._im.get_param('foo', failobj=missing,
+                                         header='content-disposition'), missing)
         # Try some missing stuff
-        unless(self._im.get_param('foobar', missing) is missing)
-        unless(self._im.get_param('attachment', missing,
-                                  header='foobar') is missing)
+        self.assertIs(self._im.get_param('foobar', missing), missing)
+        self.assertIs(self._im.get_param('attachment', missing,
+                                         header='foobar'), missing)
 
 
 
@@ -1575,13 +1572,12 @@
 
     def test_types(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         eq(self._msg.get_content_type(), 'text/plain')
         eq(self._msg.get_param('charset'), 'us-ascii')
         missing = []
-        unless(self._msg.get_param('foobar', missing) is missing)
-        unless(self._msg.get_param('charset', missing, header='foobar')
-               is missing)
+        self.assertIs(self._msg.get_param('foobar', missing), missing)
+        self.assertIs(self._msg.get_param('charset', missing, header='foobar'),
+                      missing)
 
     def test_payload(self):
         self.assertEqual(self._msg.get_payload(), 'hello there')
@@ -1663,21 +1659,20 @@
     def test_hierarchy(self):
         # convenience
         eq = self.assertEqual
-        unless = self.assertTrue
         raises = self.assertRaises
         # tests
         m = self._msg
-        unless(m.is_multipart())
+        self.assertTrue(m.is_multipart())
         eq(m.get_content_type(), 'multipart/mixed')
         eq(len(m.get_payload()), 2)
         raises(IndexError, m.get_payload, 2)
         m0 = m.get_payload(0)
         m1 = m.get_payload(1)
-        unless(m0 is self._txt)
-        unless(m1 is self._im)
+        self.assertIs(m0, self._txt)
+        self.assertIs(m1, self._im)
         eq(m.get_payload(), [m0, m1])
-        unless(not m0.is_multipart())
-        unless(not m1.is_multipart())
+        self.assertFalse(m0.is_multipart())
+        self.assertFalse(m1.is_multipart())
 
     def test_empty_multipart_idempotent(self):
         text = """\
@@ -2009,25 +2004,23 @@
 
     # test_defect_handling
     def test_same_boundary_inner_outer(self):
-        unless = self.assertTrue
         msg = self._msgobj('msg_15.txt')
         # XXX We can probably eventually do better
         inner = msg.get_payload(0)
-        unless(hasattr(inner, 'defects'))
+        self.assertTrue(hasattr(inner, 'defects'))
         self.assertEqual(len(inner.defects), 1)
-        unless(isinstance(inner.defects[0],
-                          errors.StartBoundaryNotFoundDefect))
+        self.assertIsInstance(inner.defects[0],
+                              errors.StartBoundaryNotFoundDefect)
 
     # test_defect_handling
     def test_multipart_no_boundary(self):
-        unless = self.assertTrue
         msg = self._msgobj('msg_25.txt')
-        unless(isinstance(msg.get_payload(), str))
+        self.assertIsInstance(msg.get_payload(), str)
         self.assertEqual(len(msg.defects), 2)
-        unless(isinstance(msg.defects[0],
-                          errors.NoBoundaryInMultipartDefect))
-        unless(isinstance(msg.defects[1],
-                          errors.MultipartInvariantViolationDefect))
+        self.assertIsInstance(msg.defects[0],
+                              errors.NoBoundaryInMultipartDefect)
+        self.assertIsInstance(msg.defects[1],
+                              errors.MultipartInvariantViolationDefect)
 
     multipart_msg = textwrap.dedent("""\
         Date: Wed, 14 Nov 2007 12:56:23 GMT
@@ -2125,14 +2118,13 @@
 
     # test_defect_handling
     def test_lying_multipart(self):
-        unless = self.assertTrue
         msg = self._msgobj('msg_41.txt')
-        unless(hasattr(msg, 'defects'))
+        self.assertTrue(hasattr(msg, 'defects'))
         self.assertEqual(len(msg.defects), 2)
-        unless(isinstance(msg.defects[0],
-                          errors.NoBoundaryInMultipartDefect))
-        unless(isinstance(msg.defects[1],
-                          errors.MultipartInvariantViolationDefect))
+        self.assertIsInstance(msg.defects[0],
+                              errors.NoBoundaryInMultipartDefect)
+        self.assertIsInstance(msg.defects[1],
+                              errors.MultipartInvariantViolationDefect)
 
     # test_defect_handling
     def test_missing_start_boundary(self):
@@ -2315,17 +2307,16 @@
 
     def test_valid_argument(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         subject = 'A sub-message'
         m = Message()
         m['Subject'] = subject
         r = MIMEMessage(m)
         eq(r.get_content_type(), 'message/rfc822')
         payload = r.get_payload()
-        unless(isinstance(payload, list))
+        self.assertIsInstance(payload, list)
         eq(len(payload), 1)
         subpart = payload[0]
-        unless(subpart is m)
+        self.assertIs(subpart, m)
         eq(subpart['subject'], subject)
 
     def test_bad_multipart(self):
@@ -2358,11 +2349,10 @@
 
     def test_parse_message_rfc822(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         msg = self._msgobj('msg_11.txt')
         eq(msg.get_content_type(), 'message/rfc822')
         payload = msg.get_payload()
-        unless(isinstance(payload, list))
+        self.assertIsInstance(payload, list)
         eq(len(payload), 1)
         submsg = payload[0]
         self.assertTrue(isinstance(submsg, Message))
@@ -2371,11 +2361,10 @@
 
     def test_dsn(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         # msg 16 is a Delivery Status Notification, see RFC 1894
         msg = self._msgobj('msg_16.txt')
         eq(msg.get_content_type(), 'multipart/report')
-        unless(msg.is_multipart())
+        self.assertTrue(msg.is_multipart())
         eq(len(msg.get_payload()), 3)
         # Subpart 1 is a text/plain, human readable section
         subpart = msg.get_payload(0)
@@ -2404,13 +2393,13 @@
         # message/delivery-status should treat each block as a bunch of
         # headers, i.e. a bunch of Message objects.
         dsn1 = subpart.get_payload(0)
-        unless(isinstance(dsn1, Message))
+        self.assertIsInstance(dsn1, Message)
         eq(dsn1['original-envelope-id'], '0GK500B4HD0888@cougar.noc.ucla.edu')
         eq(dsn1.get_param('dns', header='reporting-mta'), '')
         # Try a missing one <wink>
         eq(dsn1.get_param('nsd', header='reporting-mta'), None)
         dsn2 = subpart.get_payload(1)
-        unless(isinstance(dsn2, Message))
+        self.assertIsInstance(dsn2, Message)
         eq(dsn2['action'], 'failed')
         eq(dsn2.get_params(header='original-recipient'),
            [('rfc822', ''), ('jangel1@cougar.noc.ucla.edu', '')])
@@ -2419,10 +2408,10 @@
         subpart = msg.get_payload(2)
         eq(subpart.get_content_type(), 'message/rfc822')
         payload = subpart.get_payload()
-        unless(isinstance(payload, list))
+        self.assertIsInstance(payload, list)
         eq(len(payload), 1)
         subsubpart = payload[0]
-        unless(isinstance(subsubpart, Message))
+        self.assertIsInstance(subsubpart, Message)
         eq(subsubpart.get_content_type(), 'text/plain')
         eq(subsubpart['message-id'],
            '<002001c144a6$8752e060$56104586@oxy.edu>')
@@ -2720,7 +2709,6 @@
 
     def test_content_type(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         # Get a message object and reset the seek pointer for other tests
         msg, text = self._msgobj('msg_05.txt')
         eq(msg.get_content_type(), 'multipart/report')
@@ -2744,22 +2732,21 @@
         eq(msg3.get_content_type(), 'message/rfc822')
         self.assertTrue(isinstance(msg3, Message))
         payload = msg3.get_payload()
-        unless(isinstance(payload, list))
+        self.assertIsInstance(payload, list)
         eq(len(payload), 1)
         msg4 = payload[0]
-        unless(isinstance(msg4, Message))
+        self.assertIsInstance(msg4, Message)
         eq(msg4.get_payload(), 'Yadda yadda yadda' + self.linesep)
 
     def test_parser(self):
         eq = self.assertEqual
-        unless = self.assertTrue
         msg, text = self._msgobj('msg_06.txt')
         # Check some of the outer headers
         eq(msg.get_content_type(), 'message/rfc822')
         # Make sure the payload is a list of exactly one sub-Message, and that
         # that submessage has a type of text/plain
         payload = msg.get_payload()
-        unless(isinstance(payload, list))
+        self.assertIsInstance(payload, list)
         eq(len(payload), 1)
         msg1 = payload[0]
         self.assertTrue(isinstance(msg1, Message))
@@ -2795,7 +2782,6 @@
             self.assertEqual(text, s.getvalue())
 
     def test_message_from_string_with_class(self):
-        unless = self.assertTrue
         with openfile('msg_01.txt') as fp:
             text = fp.read()
 
@@ -2804,28 +2790,27 @@
             pass
 
         msg = email.message_from_string(text, MyMessage)
-        unless(isinstance(msg, MyMessage))
+        self.assertIsInstance(msg, MyMessage)
         # Try something more complicated
         with openfile('msg_02.txt') as fp:
             text = fp.read()
         msg = email.message_from_string(text, MyMessage)
         for subpart in msg.walk():
-            unless(isinstance(subpart, MyMessage))
+            self.assertIsInstance(subpart, MyMessage)
 
     def test_message_from_file_with_class(self):
-        unless = self.assertTrue
         # Create a subclass
         class MyMessage(Message):
             pass
 
         with openfile('msg_01.txt') as fp:
             msg = email.message_from_file(fp, MyMessage)
-        unless(isinstance(msg, MyMessage))
+        self.assertIsInstance(msg, MyMessage)
         # Try something more complicated
         with openfile('msg_02.txt') as fp:
             msg = email.message_from_file(fp, MyMessage)
         for subpart in msg.walk():
-            unless(isinstance(subpart, MyMessage))
+            self.assertIsInstance(subpart, MyMessage)
 
     def test_custom_message_does_not_require_arguments(self):
         class MyMessage(Message):