--- a/testing/marionette/harness/marionette/marionette_test/testcases.py
+++ b/testing/marionette/harness/marionette/marionette_test/testcases.py
@@ -71,17 +71,18 @@ class JSTest:
 class CommonTestCase(unittest.TestCase):
 
     __metaclass__ = MetaParameterized
     match_re = None
     failureException = AssertionError
     pydebugger = None
 
     def __init__(self, methodName, **kwargs):
-        unittest.TestCase.__init__(self, methodName)
+        super(CommonTestCase, self).__init__(methodName)
+
         self.loglines = []
         self.duration = 0
         self.start_time = 0
         self.expected = kwargs.pop('expected', 'pass')
         self.logger = get_default_logger()
 
     def _enter_pm(self):
         if self.pydebugger:
@@ -250,18 +251,17 @@ class CommonTestCase(unittest.TestCase):
         # a persistent circular reference which in turn would prevent
         # proper garbage collection.
         self.start_time = time.time()
         self.marionette = self._marionette_weakref()
         if self.marionette.session is None:
             self.marionette.start_session()
         self.marionette.reset_timeouts()
 
-    def tearDown(self):
-        pass
+        super(CommonTestCase, self).setUp()
 
     def cleanTest(self):
         self._deleteSession()
 
     def _deleteSession(self):
         if hasattr(self, 'start_time'):
             self.duration = time.time() - self.start_time
         if hasattr(self.marionette, 'session'):
@@ -426,17 +426,18 @@ class MarionetteTestCase(CommonTestCase)
 
     def __init__(self, marionette_weakref, methodName='runTest',
                  filepath='', **kwargs):
         self._marionette_weakref = marionette_weakref
         self.marionette = None
         self.methodName = methodName
         self.filepath = filepath
         self.testvars = kwargs.pop('testvars', None)
-        CommonTestCase.__init__(self, methodName, **kwargs)
+
+        super(MarionetteTestCase, self).__init__(methodName, **kwargs)
 
     @classmethod
     def add_tests_to_suite(cls, mod_name, filepath, suite, testloader, marionette,
                            testvars, **kwargs):
         # since we use imp.load_source to load test modules, if a module
         # is loaded with the same name as another one the module would just be
         # reloaded.
         #
@@ -460,17 +461,17 @@ class MarionetteTestCase(CommonTestCase)
                 for testname in testnames:
                     suite.addTest(obj(weakref.ref(marionette),
                                   methodName=testname,
                                   filepath=filepath,
                                   testvars=testvars,
                                   **kwargs))
 
     def setUp(self):
-        CommonTestCase.setUp(self)
+        super(MarionetteTestCase, self).setUp()
         self.marionette.test_name = self.test_name
         self.marionette.execute_script("log('TEST-START: {0}:{1}')"
                                        .format(self.filepath.replace('\\', '\\\\'),
                                                self.methodName),
                                        sandbox="simpletest")
 
     def tearDown(self):
         # In the case no session is active (eg. the application was quit), start
@@ -486,17 +487,17 @@ class MarionetteTestCase(CommonTestCase)
                                                        self.methodName),
                                                sandbox="simpletest")
                 self.marionette.test_name = None
             except (MarionetteException, IOError):
                 # We have tried to log the test end when there is no listener
                 # object that we can access
                 pass
 
-        CommonTestCase.tearDown(self)
+        super(MarionetteTestCase, self).tearDown()
 
     def wait_for_condition(self, method, timeout=30):
         timeout = float(timeout) + time.time()
         while time.time() < timeout:
             value = method(self.marionette)
             if value:
                 return value
             time.sleep(0.5)
@@ -508,17 +509,18 @@ class MarionetteJSTestCase(CommonTestCas
 
     match_re = re.compile(r"test_(.*)\.js$")
 
     def __init__(self, marionette_weakref, methodName='runTest', jsFile=None, **kwargs):
         assert(jsFile)
         self.jsFile = jsFile
         self._marionette_weakref = marionette_weakref
         self.marionette = None
-        CommonTestCase.__init__(self, methodName)
+
+        super(MarionetteJSTestCase, self).__init__(methodName)
 
     @classmethod
     def add_tests_to_suite(cls, mod_name, filepath, suite, testloader, marionette,
                            testvars, **kwargs):
         suite.addTest(cls(weakref.ref(marionette), jsFile=filepath, **kwargs))
 
     def runTest(self):
         if self.marionette.session is None: