diff -r 4e9eabe3e24f Doc/library/unittest.rst
--- a/Doc/library/unittest.rst	Tue May 15 20:04:25 2012 +0200
+++ b/Doc/library/unittest.rst	Tue May 15 17:12:17 2012 -0400
@@ -859,6 +859,12 @@
    | :meth:`assertNotIsInstance(a, b)        | ``not isinstance(a, b)``    | 3.2           |
    | <TestCase.assertNotIsInstance>`         |                             |               |
    +-----------------------------------------+-----------------------------+---------------+
+   | :meth:`assertIsSubclass(a, b)           | ``issubclass(a, b)``        | 3.3           |
+   | <TestCase.assertIsSubclass>`            |                             |               |
+   +-----------------------------------------+-----------------------------+---------------+
+   | :meth:`assertNotIsSubclass(a, b)        | ``not issubclass(a, b)``    | 3.3           |
+   | <TestCase.assertNotIsSubclass>`         |                             |               |
+   +-----------------------------------------+-----------------------------+---------------+
 
    All the assert methods accept a *msg* argument that, if specified, is used
    as the error message on failure (see also :data:`longMessage`).
@@ -938,6 +944,15 @@
       .. versionadded:: 3.2
 
 
+   .. method:: assertIsSubclass(cls, parent_cls, msg=None)
+               assertNotIsSubclass(cls, parent_cls, msg=None)
+
+      Test that *cls* is (or is not) a subclass of *parent_cls* (which can be a
+      class or a tuple of classes, as supported by :func:`issubclass`).
+
+      .. versionadded:: 3.3
+
+
 
    It is also possible to check that exceptions and warnings are raised using
    the following methods:
diff -r 4e9eabe3e24f Lib/unittest/case.py
--- a/Lib/unittest/case.py	Tue May 15 20:04:25 2012 +0200
+++ b/Lib/unittest/case.py	Tue May 15 17:12:17 2012 -0400
@@ -1069,6 +1069,19 @@
             standardMsg = '%s is an instance of %r' % (safe_repr(obj), cls)
             self.fail(self._formatMessage(msg, standardMsg))
 
+    def assertIsSubclass(self, cls, parent_cls, msg=None):
+        """Same as self.assertTrue(issubclass(cls, parent_cls)), with a nicer
+        default message."""
+        if not issubclass(cls, parent_cls):
+            standardMsg = '%r is not a subclass of %r' % (cls, parent_cls)
+            self.fail(self._formatMessage(msg, standardMsg))
+
+    def assertNotIsSubclass(self, cls, parent_cls, msg=None):
+        """Included for symmetry with assertIsSubclass."""
+        if issubclass(cls, parent_cls):
+            standardMsg = '%r is a subclass of %r' % (cls, parent_cls)
+            self.fail(self._formatMessage(msg, standardMsg))
+
     def assertRaisesRegex(self, expected_exception, expected_regex,
                           callable_obj=None, *args, **kwargs):
         """Asserts that the message in a raised exception matches a regex.
diff -r 4e9eabe3e24f Lib/unittest/test/test_case.py
--- a/Lib/unittest/test/test_case.py	Tue May 15 20:04:25 2012 +0200
+++ b/Lib/unittest/test/test_case.py	Tue May 15 17:12:17 2012 -0400
@@ -503,6 +503,30 @@
         self.assertRaises(self.failureException, self.assertNotIsInstance,
                           thing, list)
 
+    def testAssertIsSubclass(self):
+        class Foo(object):
+            pass
+        class Bar(Foo):
+            pass
+        class Baz(object):
+            pass
+
+        self.assertIsSubclass(Bar, Foo)
+        self.assertRaises(self.failureException, self.assertIsSubclass,
+                          Bar, Baz)
+
+    def testAssertNotIsSubclass(self):
+        class Foo(object):
+            pass
+        class Bar(Foo):
+            pass
+        class Baz(object):
+            pass
+
+        self.assertNotIsSubclass(Bar, Baz)
+        self.assertRaises(self.failureException, self.assertNotIsSubclass,
+                          Bar, Foo)
+
     def testAssertIn(self):
         animals = {'monkey': 'banana', 'cow': 'grass', 'seal': 'fish'}
 
diff -r 4e9eabe3e24f Misc/ACKS
--- a/Misc/ACKS	Tue May 15 20:04:25 2012 +0200
+++ b/Misc/ACKS	Tue May 15 17:12:17 2012 -0400
@@ -959,6 +959,7 @@
 Eric V. Smith
 Gregory P. Smith
 Mark Smith
+Patrick Smith
 Rafal Smotrzyk
 Eric Snow
 Dirk Soede