Addition of setUpClass and setUpModule shared fixtures to unittest.
diff --git a/Lib/unittest/suite.py b/Lib/unittest/suite.py
index 60e9b6c..cccc7ef 100644
--- a/Lib/unittest/suite.py
+++ b/Lib/unittest/suite.py
@@ -1,17 +1,13 @@
 """TestSuite"""
 
+import sys
+
 from . import case
 from . import util
 
 
-class TestSuite(object):
-    """A test suite is a composite test consisting of a number of TestCases.
-
-    For use, create an instance of TestSuite, then add test case instances.
-    When all tests have been added, the suite can be passed to a test
-    runner, such as TextTestRunner. It will run the individual test cases
-    in the order in which they were added, aggregating the results. When
-    subclassing, do not forget to call the base class constructor.
+class BaseTestSuite(object):
+    """A simple test suite that doesn't provide class or module shared fixtures.
     """
     def __init__(self, tests=()):
         self._tests = []
@@ -70,3 +66,190 @@
         """Run the tests without collecting errors in a TestResult"""
         for test in self:
             test.debug()
+
+
+class TestSuite(BaseTestSuite):
+    """A test suite is a composite test consisting of a number of TestCases.
+
+    For use, create an instance of TestSuite, then add test case instances.
+    When all tests have been added, the suite can be passed to a test
+    runner, such as TextTestRunner. It will run the individual test cases
+    in the order in which they were added, aggregating the results. When
+    subclassing, do not forget to call the base class constructor.
+    """
+
+
+    def run(self, result):
+        self._wrapped_run(result)
+        self._tearDownPreviousClass(None, result)
+        self._handleModuleTearDown(result)
+        return result
+
+    ################################
+    # private methods
+    def _wrapped_run(self, result):
+        for test in self:
+            if result.shouldStop:
+                break
+
+            if _isnotsuite(test):
+                self._tearDownPreviousClass(test, result)
+                self._handleModuleFixture(test, result)
+                self._handleClassSetUp(test, result)
+                result._previousTestClass = test.__class__
+
+                if (getattr(test.__class__, '_classSetupFailed', False) or
+                    getattr(result, '_moduleSetUpFailed', False)):
+                    continue
+
+            if hasattr(test, '_wrapped_run'):
+                test._wrapped_run(result)
+            else:
+                test(result)
+
+    def _handleClassSetUp(self, test, result):
+        previousClass = getattr(result, '_previousTestClass', None)
+        currentClass = test.__class__
+        if currentClass == previousClass:
+            return
+        if result._moduleSetUpFailed:
+            return
+        if getattr(currentClass, "__unittest_skip__", False):
+            return
+
+        currentClass._classSetupFailed = False
+
+        setUpClass = getattr(currentClass, 'setUpClass', None)
+        if setUpClass is not None:
+            try:
+                setUpClass()
+            except:
+                currentClass._classSetupFailed = True
+                self._addClassSetUpError(result, currentClass)
+
+    def _get_previous_module(self, result):
+        previousModule = None
+        previousClass = getattr(result, '_previousTestClass', None)
+        if previousClass is not None:
+            previousModule = previousClass.__module__
+        return previousModule
+
+
+    def _handleModuleFixture(self, test, result):
+        previousModule = self._get_previous_module(result)
+        currentModule = test.__class__.__module__
+        if currentModule == previousModule:
+            return
+
+        self._handleModuleTearDown(result)
+
+
+        result._moduleSetUpFailed = False
+        try:
+            module = sys.modules[currentModule]
+        except KeyError:
+            return
+        setUpModule = getattr(module, 'setUpModule', None)
+        if setUpModule is not None:
+            try:
+                setUpModule()
+            except:
+                result._moduleSetUpFailed = True
+                error = _ErrorHolder('setUpModule (%s)' % currentModule)
+                result.addError(error, sys.exc_info())
+
+    def _handleModuleTearDown(self, result):
+        previousModule = self._get_previous_module(result)
+        if previousModule is None:
+            return
+        if result._moduleSetUpFailed:
+            return
+
+        try:
+            module = sys.modules[previousModule]
+        except KeyError:
+            return
+
+        tearDownModule = getattr(module, 'tearDownModule', None)
+        if tearDownModule is not None:
+            try:
+                tearDownModule()
+            except:
+                error = _ErrorHolder('tearDownModule (%s)' % previousModule)
+                result.addError(error, sys.exc_info())
+
+    def _tearDownPreviousClass(self, test, result):
+        previousClass = getattr(result, '_previousTestClass', None)
+        currentClass = test.__class__
+        if currentClass == previousClass:
+            return
+        if getattr(previousClass, '_classSetupFailed', False):
+            return
+        if getattr(result, '_moduleSetUpFailed', False):
+            return
+        if getattr(previousClass, "__unittest_skip__", False):
+            return
+
+        tearDownClass = getattr(previousClass, 'tearDownClass', None)
+        if tearDownClass is not None:
+            try:
+                tearDownClass()
+            except:
+                self._addClassTearDownError(result)
+
+    def _addClassTearDownError(self, result):
+        className = util.strclass(result._previousTestClass)
+        error = _ErrorHolder('classTearDown (%s)' % className)
+        result.addError(error, sys.exc_info())
+
+    def _addClassSetUpError(self, result, klass):
+        className = util.strclass(klass)
+        error = _ErrorHolder('classSetUp (%s)' % className)
+        result.addError(error, sys.exc_info())
+
+
+class _ErrorHolder(object):
+    """
+    Placeholder for a TestCase inside a result. As far as a TestResult
+    is concerned, this looks exactly like a unit test. Used to insert
+    arbitrary errors into a test suite run.
+    """
+    # Inspired by the ErrorHolder from Twisted:
+    # http://twistedmatrix.com/trac/browser/trunk/twisted/trial/runner.py
+
+    # attribute used by TestResult._exc_info_to_string
+    failureException = None
+
+    def __init__(self, description):
+        self.description = description
+
+    def id(self):
+        return self.description
+
+    def shortDescription(self):
+        return None
+
+    def __repr__(self):
+        return "<ErrorHolder description=%r>" % (self.description,)
+
+    def __str__(self):
+        return self.id()
+
+    def run(self, result):
+        # could call result.addError(...) - but this test-like object
+        # shouldn't be run anyway
+        pass
+
+    def __call__(self, result):
+        return self.run(result)
+
+    def countTestCases(self):
+        return 0
+
+def _isnotsuite(test):
+    "A crude way to tell apart testcases and suites with duck-typing"
+    try:
+        iter(test)
+    except TypeError:
+        return True
+    return False