diff --git a/cms/djangoapps/contentstore/tests/test_assets.py b/cms/djangoapps/contentstore/tests/test_assets.py
index b627237729..2f158cfda6 100644
--- a/cms/djangoapps/contentstore/tests/test_assets.py
+++ b/cms/djangoapps/contentstore/tests/test_assets.py
@@ -60,11 +60,11 @@ class UploadTestCase(CourseTestCase):
         f = BytesIO("sample content")
         f.name = "sample.txt"
         resp = self.client.post(self.url, {"name": "my-name", "file": f})
-        self.assert2XX(resp.status_code)
+        self.assertEquals(resp.status_code, 200)
 
     def test_no_file(self):
         resp = self.client.post(self.url, {"name": "file.txt"})
-        self.assert4XX(resp.status_code)
+        self.assertEquals(resp.status_code, 400)
 
     def test_get(self):
         resp = self.client.get(self.url)
diff --git a/cms/djangoapps/contentstore/tests/test_contentstore.py b/cms/djangoapps/contentstore/tests/test_contentstore.py
index f03ee3b81a..14e54f6f56 100644
--- a/cms/djangoapps/contentstore/tests/test_contentstore.py
+++ b/cms/djangoapps/contentstore/tests/test_contentstore.py
@@ -1408,7 +1408,7 @@ class ContentStoreTest(ModuleStoreTestCase):
                                                'course': loc.course,
                                                'name': loc.name}))
 
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         self.assertContains(resp, 'Chapter 2')
 
         # go to various pages
@@ -1418,92 +1418,92 @@ class ContentStoreTest(ModuleStoreTestCase):
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # export page
         resp = self.client.get(reverse('export_course',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # manage users
         resp = self.client.get(reverse('manage_users',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # course info
         resp = self.client.get(reverse('course_info',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # settings_details
         resp = self.client.get(reverse('settings_details',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # settings_details
         resp = self.client.get(reverse('settings_grading',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # static_pages
         resp = self.client.get(reverse('static_pages',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'coursename': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # static_pages
         resp = self.client.get(reverse('asset_index',
                                        kwargs={'org': loc.org,
                                                'course': loc.course,
                                                'name': loc.name}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # go look at a subsection page
         subsection_location = loc.replace(category='sequential', name='test_sequence')
         resp = self.client.get(reverse('edit_subsection',
                                        kwargs={'location': subsection_location.url()}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # go look at the Edit page
         unit_location = loc.replace(category='vertical', name='test_vertical')
         resp = self.client.get(reverse('edit_unit',
                                        kwargs={'location': unit_location.url()}))
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # delete a component
         del_loc = loc.replace(category='html', name='test_html')
         resp = self.client.post(reverse('delete_item'),
                                 json.dumps({'id': del_loc.url()}), "application/json")
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
         # delete a unit
         del_loc = loc.replace(category='vertical', name='test_vertical')
         resp = self.client.post(reverse('delete_item'),
                                 json.dumps({'id': del_loc.url()}), "application/json")
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
         # delete a unit
         del_loc = loc.replace(category='sequential', name='test_sequence')
         resp = self.client.post(reverse('delete_item'),
                                 json.dumps({'id': del_loc.url()}), "application/json")
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
         # delete a chapter
         del_loc = loc.replace(category='chapter', name='chapter_2')
         resp = self.client.post(reverse('delete_item'),
                                 json.dumps({'id': del_loc.url()}), "application/json")
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
     def test_import_into_new_course_id(self):
         module_store = modulestore('direct')
diff --git a/cms/djangoapps/contentstore/tests/test_course_settings.py b/cms/djangoapps/contentstore/tests/test_course_settings.py
index dbdf8b3f6e..524dde07e5 100644
--- a/cms/djangoapps/contentstore/tests/test_course_settings.py
+++ b/cms/djangoapps/contentstore/tests/test_course_settings.py
@@ -439,12 +439,12 @@ class CourseGraderUpdatesTest(CourseTestCase):
 
     def test_get(self):
         resp = self.client.get(self.url)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         obj = json.loads(resp.content)
 
     def test_delete(self):
         resp = self.client.delete(self.url)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
     def test_post(self):
         grader = {
@@ -455,5 +455,5 @@ class CourseGraderUpdatesTest(CourseTestCase):
             "weight": 17.3,
         }
         resp = self.client.post(self.url, grader)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         obj = json.loads(resp.content)
diff --git a/cms/djangoapps/contentstore/tests/test_item.py b/cms/djangoapps/contentstore/tests/test_item.py
index 260444a8f7..e5ff992cb8 100644
--- a/cms/djangoapps/contentstore/tests/test_item.py
+++ b/cms/djangoapps/contentstore/tests/test_item.py
@@ -34,7 +34,7 @@ class DeleteItem(CourseTestCase):
             resp.content,
             "application/json"
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
 
 
 class TestCreateItem(CourseTestCase):
diff --git a/cms/djangoapps/contentstore/tests/test_textbooks.py b/cms/djangoapps/contentstore/tests/test_textbooks.py
index a21a1b1023..950d0f780e 100644
--- a/cms/djangoapps/contentstore/tests/test_textbooks.py
+++ b/cms/djangoapps/contentstore/tests/test_textbooks.py
@@ -23,7 +23,7 @@ class TextbookIndexTestCase(CourseTestCase):
     def test_view_index(self):
         "Basic check that the textbook index page responds correctly"
         resp = self.client.get(self.url)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         # we don't have resp.context right now,
         # due to bugs in our testing harness :(
         if resp.context:
@@ -36,7 +36,7 @@ class TextbookIndexTestCase(CourseTestCase):
             HTTP_ACCEPT="application/json",
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         obj = json.loads(resp.content)
         self.assertEqual(self.course.pdf_textbooks, obj)
 
@@ -73,7 +73,7 @@ class TextbookIndexTestCase(CourseTestCase):
             HTTP_ACCEPT="application/json",
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         obj = json.loads(resp.content)
         self.assertEqual(content, obj)
 
@@ -90,7 +90,7 @@ class TextbookIndexTestCase(CourseTestCase):
             HTTP_ACCEPT="application/json",
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
 
         # reload course
         store = get_modulestore(self.course.location)
@@ -111,7 +111,7 @@ class TextbookIndexTestCase(CourseTestCase):
             HTTP_ACCEPT="application/json",
             HTTP_X_REQUESTED_WITH='XMLHttpRequest'
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         obj = json.loads(resp.content)
         self.assertIn("error", obj)
 
@@ -184,7 +184,7 @@ class TextbookCreateTestCase(CourseTestCase):
             HTTP_ACCEPT="application/json",
             HTTP_X_REQUESTED_WITH="XMLHttpRequest",
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         self.assertNotIn("Location", resp)
 
 
@@ -238,14 +238,14 @@ class TextbookByIdTestCase(CourseTestCase):
     def test_get_1(self):
         "Get the first textbook"
         resp = self.client.get(self.url1)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         compare = json.loads(resp.content)
         self.assertEqual(compare, self.textbook1)
 
     def test_get_2(self):
         "Get the second textbook"
         resp = self.client.get(self.url2)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         compare = json.loads(resp.content)
         self.assertEqual(compare, self.textbook2)
 
@@ -257,7 +257,7 @@ class TextbookByIdTestCase(CourseTestCase):
     def test_delete(self):
         "Delete a textbook by ID"
         resp = self.client.delete(self.url1)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         course = self.store.get_item(self.course.location)
         self.assertEqual(course.pdf_textbooks, [self.textbook2])
 
@@ -288,7 +288,7 @@ class TextbookByIdTestCase(CourseTestCase):
         )
         self.assertEqual(resp.status_code, 201)
         resp2 = self.client.get(url)
-        self.assert2XX(resp2.status_code)
+        self.assertEqual(resp2.status_code, 200)
         compare = json.loads(resp2.content)
         self.assertEqual(compare, textbook)
         course = self.store.get_item(self.course.location)
@@ -311,7 +311,7 @@ class TextbookByIdTestCase(CourseTestCase):
         )
         self.assertEqual(resp.status_code, 201)
         resp2 = self.client.get(self.url2)
-        self.assert2XX(resp2.status_code)
+        self.assertEqual(resp2.status_code, 200)
         compare = json.loads(resp2.content)
         self.assertEqual(compare, replacement)
         course = self.store.get_item(self.course.location)
diff --git a/cms/djangoapps/contentstore/tests/test_users.py b/cms/djangoapps/contentstore/tests/test_users.py
index cbb8aa8b01..80b2364c43 100644
--- a/cms/djangoapps/contentstore/tests/test_users.py
+++ b/cms/djangoapps/contentstore/tests/test_users.py
@@ -72,13 +72,13 @@ class UsersTestCase(CourseTestCase):
 
     def test_detail_inactive(self):
         resp = self.client.get(self.inactive_detail_url)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 200)
         result = json.loads(resp.content)
         self.assertFalse(result["active"])
 
     def test_detail_invalid(self):
         resp = self.client.get(self.invalid_detail_url)
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 404)
         result = json.loads(resp.content)
         self.assertIn("error", result)
 
@@ -87,7 +87,7 @@ class UsersTestCase(CourseTestCase):
             self.detail_url,
             data={"role": None},
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -103,7 +103,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -122,7 +122,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -142,7 +142,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -157,7 +157,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         result = json.loads(resp.content)
         self.assertIn("error", result)
         self.assert_not_enrolled()
@@ -169,7 +169,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         result = json.loads(resp.content)
         self.assertIn("error", result)
         self.assert_not_enrolled()
@@ -180,7 +180,7 @@ class UsersTestCase(CourseTestCase):
             data={"role": "staff"},
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -197,7 +197,7 @@ class UsersTestCase(CourseTestCase):
             self.detail_url,
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -214,7 +214,7 @@ class UsersTestCase(CourseTestCase):
             self.detail_url,
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         ext_user = User.objects.get(email=self.ext_user.email)
         groups = [g.name for g in ext_user.groups.all()]
@@ -273,7 +273,7 @@ class UsersTestCase(CourseTestCase):
             data={"role": "instructor"},
             HTTP_ACCEPT="application/json",
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         result = json.loads(resp.content)
         self.assertIn("error", result)
 
@@ -288,7 +288,7 @@ class UsersTestCase(CourseTestCase):
             data={"role": "instructor"},
             HTTP_ACCEPT="application/json",
         )
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         result = json.loads(resp.content)
         self.assertIn("error", result)
 
@@ -306,7 +306,7 @@ class UsersTestCase(CourseTestCase):
         })
 
         resp = self.client.delete(self_url)
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         # reload user from DB
         user = User.objects.get(email=self.user.email)
         groups = [g.name for g in user.groups.all()]
@@ -321,7 +321,7 @@ class UsersTestCase(CourseTestCase):
         self.ext_user.save()
 
         resp = self.client.delete(self.detail_url)
-        self.assert4XX(resp.status_code)
+        self.assertEqual(resp.status_code, 400)
         result = json.loads(resp.content)
         self.assertIn("error", result)
         # reload user from DB
@@ -347,7 +347,7 @@ class UsersTestCase(CourseTestCase):
             self.detail_url,
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         self.assert_enrolled()
 
     def test_staff_to_instructor_still_enrolled(self):
@@ -366,7 +366,7 @@ class UsersTestCase(CourseTestCase):
             content_type="application/json",
             HTTP_ACCEPT="application/json",
         )
-        self.assert2XX(resp.status_code)
+        self.assertEqual(resp.status_code, 204)
         self.assert_enrolled()
 
     def assert_not_enrolled(self):
diff --git a/common/djangoapps/course_groups/tests/tests.py b/common/djangoapps/course_groups/tests/tests.py
index 2e519edb30..a17df56a71 100644
--- a/common/djangoapps/course_groups/tests/tests.py
+++ b/common/djangoapps/course_groups/tests/tests.py
@@ -8,19 +8,20 @@ from course_groups.models import CourseUserGroup
 from course_groups.cohorts import (get_cohort, get_course_cohorts,
                                    is_commentable_cohorted, get_cohort_by_name)
 
-from xmodule.modulestore.django import modulestore, _MODULESTORES
+from xmodule.modulestore.django import modulestore, clear_existing_modulestores
 
-from xmodule.modulestore.tests.django_utils import xml_store_config
+from xmodule.modulestore.tests.django_utils import mixed_store_config
 
 # NOTE: running this with the lms.envs.test config works without
 # manually overriding the modulestore.  However, running with
 # cms.envs.test doesn't.
 
 TEST_DATA_DIR = settings.COMMON_TEST_DATA_ROOT
-TEST_DATA_XML_MODULESTORE = xml_store_config(TEST_DATA_DIR)
+TEST_MAPPING = {'edX/toy/2012_Fall': 'xml'}
+TEST_DATA_MIXED_MODULESTORE = mixed_store_config(TEST_DATA_DIR, TEST_MAPPING)
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestCohorts(django.test.TestCase):
 
     @staticmethod
@@ -82,9 +83,7 @@ class TestCohorts(django.test.TestCase):
         """
         Make sure that course is reloaded every time--clear out the modulestore.
         """
-        # don't like this, but don't know a better way to undo all changes made
-        # to course.  We don't have a course.clone() method.
-        _MODULESTORES.clear()
+        clear_existing_modulestores()
 
     def test_get_cohort(self):
         """
diff --git a/common/djangoapps/external_auth/tests/test_shib.py b/common/djangoapps/external_auth/tests/test_shib.py
index 6bb9c38e6f..0355730256 100644
--- a/common/djangoapps/external_auth/tests/test_shib.py
+++ b/common/djangoapps/external_auth/tests/test_shib.py
@@ -14,11 +14,9 @@ from django.contrib.auth.models import AnonymousUser, User
 from django.utils.importlib import import_module
 
 from xmodule.modulestore.tests.factories import CourseFactory
-from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase, mixed_store_config
 from xmodule.modulestore.inheritance import own_metadata
-from xmodule.modulestore.django import modulestore
-
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from xmodule.modulestore.django import editable_modulestore
 
 from external_auth.models import ExternalAuthMap
 from external_auth.views import shib_login, course_specific_login, course_specific_register
@@ -27,6 +25,8 @@ from student.views import create_account, change_enrollment
 from student.models import UserProfile, Registration, CourseEnrollment
 from student.tests.factories import UserFactory
 
+TEST_DATA_MIXED_MODULESTORE = mixed_store_config(settings.COMMON_TEST_DATA_ROOT, {})
+
 # Shib is supposed to provide 'REMOTE_USER', 'givenName', 'sn', 'mail', 'Shib-Identity-Provider'
 # attributes via request.META.  We can count on 'Shib-Identity-Provider', and 'REMOTE_USER' being present
 # b/c of how mod_shib works but should test the behavior with the rest of the attributes present/missing
@@ -64,7 +64,7 @@ def gen_all_identities():
                 yield _build_identity_dict(mail, given_name, surname)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE, SESSION_ENGINE='django.contrib.sessions.backends.cache')
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE, SESSION_ENGINE='django.contrib.sessions.backends.cache')
 class ShibSPTest(ModuleStoreTestCase):
     """
     Tests for the Shibboleth SP, which communicates via request.META
@@ -73,7 +73,7 @@ class ShibSPTest(ModuleStoreTestCase):
     request_factory = RequestFactory()
 
     def setUp(self):
-        self.store = modulestore()
+        self.store = editable_modulestore()
 
     @unittest.skipUnless(settings.MITX_FEATURES.get('AUTH_USE_SHIB'), True)
     def test_exception_shib_login(self):
diff --git a/common/djangoapps/terrain/browser.py b/common/djangoapps/terrain/browser.py
index cf53aa4f69..4bf1aea40c 100644
--- a/common/djangoapps/terrain/browser.py
+++ b/common/djangoapps/terrain/browser.py
@@ -161,9 +161,10 @@ def reset_databases(scenario):
     mongo = MongoClient()
     mongo.drop_database(settings.CONTENTSTORE['OPTIONS']['db'])
     _CONTENTSTORE.clear()
-    modulestore = xmodule.modulestore.django.modulestore()
+
+    modulestore = xmodule.modulestore.django.editable_modulestore()
     modulestore.collection.drop()
-    xmodule.modulestore.django._MODULESTORES.clear()
+    xmodule.modulestore.django.clear_existing_modulestores()
 
 
 # Uncomment below to trigger a screenshot on error
diff --git a/common/djangoapps/terrain/course_helpers.py b/common/djangoapps/terrain/course_helpers.py
index eca3290080..fc01d25d66 100644
--- a/common/djangoapps/terrain/course_helpers.py
+++ b/common/djangoapps/terrain/course_helpers.py
@@ -10,7 +10,7 @@ from django.contrib.auth import authenticate, login
 from django.contrib.auth.middleware import AuthenticationMiddleware
 from django.contrib.sessions.middleware import SessionMiddleware
 from student.models import CourseEnrollment
-from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.django import editable_modulestore
 from xmodule.contentstore.django import contentstore
 from urllib import quote_plus
 
@@ -60,11 +60,9 @@ def register_by_course_id(course_id, is_staff=False):
 @world.absorb
 def clear_courses():
     # Flush and initialize the module store
-    # It needs the templates because it creates new records
-    # by cloning from the template.
     # Note that if your test module gets in some weird state
     # (though it shouldn't), do this manually
     # from the bash shell to drop it:
     # $ mongo test_xmodule --eval "db.dropDatabase()"
-    modulestore().collection.drop()
+    editable_modulestore().collection.drop()
     contentstore().fs_files.drop()
diff --git a/common/lib/xmodule/xmodule/js/libpeerconnection.log b/common/lib/xmodule/xmodule/js/libpeerconnection.log
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/common/lib/xmodule/xmodule/modulestore/django.py b/common/lib/xmodule/xmodule/modulestore/django.py
index fb427f49ec..b239e5f1d4 100644
--- a/common/lib/xmodule/xmodule/modulestore/django.py
+++ b/common/lib/xmodule/xmodule/modulestore/django.py
@@ -55,6 +55,7 @@ def modulestore(name='default'):
 
     return _MODULESTORES[name]
 
+
 _loc_singleton = None
 def loc_mapper():
     """
@@ -69,3 +70,42 @@ def loc_mapper():
         _loc_singleton = LocMapperStore(settings.modulestore_options)
     return _loc_singleton
 
+
+def clear_existing_modulestores():
+    """
+    Clear the existing modulestore instances, causing
+    them to be re-created when accessed again.
+
+    This is useful for flushing state between unit tests.
+    """
+    _MODULESTORES.clear()
+
+
+def editable_modulestore(name='default'):
+    """
+    Retrieve a modulestore that we can modify.
+    This is useful for tests that need to insert test
+    data into the modulestore.
+
+    Currently, only Mongo-backed modulestores can be modified.
+    Returns `None` if no editable modulestore is available.
+    """
+
+    # Try to retrieve the ModuleStore
+    # Depending on the settings, this may or may not
+    # be editable.
+    store = modulestore(name)
+
+    # If this is a `MixedModuleStore`, then we will need
+    # to retrieve the actual Mongo instance.
+    # We assume that the default is Mongo.
+    if hasattr(store, 'modulestores'):
+        store = store.modulestores['default']
+
+    # At this point, we either have the ability to create
+    # items in the store, or we do not.
+    if hasattr(store, 'create_xmodule'):
+        return store
+
+    else:
+        return None
diff --git a/common/lib/xmodule/xmodule/modulestore/tests/django_utils.py b/common/lib/xmodule/xmodule/modulestore/tests/django_utils.py
index 4f998d57fb..1f856d7eba 100644
--- a/common/lib/xmodule/xmodule/modulestore/tests/django_utils.py
+++ b/common/lib/xmodule/xmodule/modulestore/tests/django_utils.py
@@ -1,11 +1,46 @@
+"""
+Modulestore configuration for test cases.
+"""
 
-import copy
 from uuid import uuid4
 from django.test import TestCase
+from xmodule.modulestore.django import editable_modulestore, \
+    clear_existing_modulestores
 
-from django.conf import settings
-import xmodule.modulestore.django
-from unittest.util import safe_repr
+
+def mixed_store_config(data_dir, mappings):
+    """
+    Return a `MixedModuleStore` configuration, which provides
+    access to both Mongo- and XML-backed courses.
+
+    `data_dir` is the directory from which to load XML-backed courses.
+    `mappings` is a dictionary mapping course IDs to modulestores, for example:
+
+        {
+            'MITx/2.01x/2013_Spring': 'xml',
+            'edx/999/2013_Spring': 'default'
+        }
+
+    where 'xml' and 'default' are the two options provided by this configuration,
+    mapping (respectively) to XML-backed and Mongo-backed modulestores..
+    """
+    mongo_config = mongo_store_config(data_dir)
+    xml_config = xml_store_config(data_dir)
+
+    store = {
+        'default': {
+            'ENGINE': 'xmodule.modulestore.mixed.MixedModuleStore',
+            'OPTIONS': {
+                'mappings': mappings,
+                'stores': {
+                    'default': mongo_config['default'],
+                    'xml': xml_config['default']
+                }
+            }
+        }
+    }
+    store['direct'] = store['default']
+    return store
 
 
 def mongo_store_config(data_dir):
@@ -27,6 +62,7 @@ def mongo_store_config(data_dir):
             }
         }
     }
+
     store['direct'] = store['default']
     return store
 
@@ -45,23 +81,22 @@ def draft_mongo_store_config(data_dir):
         'render_template': 'mitxmako.shortcuts.render_to_string'
     }
 
-    return {
+    store = {
         'default': {
             'ENGINE': 'xmodule.modulestore.mongo.draft.DraftModuleStore',
             'OPTIONS': modulestore_options
-        },
-        'direct': {
-            'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',
-            'OPTIONS': modulestore_options
         }
     }
 
+    store['direct'] = store['default']
+    return store
+
 
 def xml_store_config(data_dir):
     """
     Defines default module store using XMLModuleStore.
     """
-    return {
+    store = {
         'default': {
             'ENGINE': 'xmodule.modulestore.xml.XMLModuleStore',
             'OPTIONS': {
@@ -71,12 +106,48 @@ def xml_store_config(data_dir):
         }
     }
 
+    store['direct'] = store['default']
+    return store
+
 
 class ModuleStoreTestCase(TestCase):
-    """ Subclass for any test case that uses the mongodb
-    module store. This populates a uniquely named modulestore
-    collection with templates before running the TestCase
-    and drops it they are finished. """
+    """
+    Subclass for any test case that uses a ModuleStore.
+    Ensures that the ModuleStore is cleaned before/after each test.
+
+    Usage:
+
+        1. Create a subclass of `ModuleStoreTestCase`
+        2. Use Django's @override_settings decorator to use
+           the desired modulestore configuration.
+
+           For example:
+
+               MIXED_CONFIG = mixed_store_config(data_dir, mappings)
+
+               @override_settings(MODULESTORE=MIXED_CONFIG)
+               class FooTest(ModuleStoreTestCase):
+                   # ...
+
+        3. Use factories (e.g. `CourseFactory`, `ItemFactory`) to populate
+           the modulestore with test data.
+
+    NOTE:
+        * For Mongo-backed courses (created with `CourseFactory`),
+          the state of the course will be reset before/after each
+          test method executes.
+
+        * For XML-backed courses, the course state will NOT
+          reset between test methods (although it will reset
+          between test classes)
+
+          The reason is: XML courses are not editable, so to reset
+          a course you have to reload it from disk, which is slow.
+
+          If you do need to reset an XML course, use
+          `clear_existing_modulestores()` directly in
+          your `setUp()` method.
+    """
 
     @staticmethod
     def update_course(course, data):
@@ -89,107 +160,68 @@ class ModuleStoreTestCase(TestCase):
 
         'data' is a dictionary with an entry for each CourseField we want to update.
         """
-        store = xmodule.modulestore.django.modulestore()
+        store = editable_modulestore('direct')
         store.update_metadata(course.location, data)
         updated_course = store.get_instance(course.id, course.location)
         return updated_course
 
     @staticmethod
-    def flush_mongo_except_templates():
+    def drop_mongo_collection():
         """
-        Delete everything in the module store except templates.
+        If using a Mongo-backed modulestore, drop the collection.
         """
-        modulestore = xmodule.modulestore.django.modulestore()
 
-        # This query means: every item in the collection
-        # that is not a template
-        query = {"_id.course": {"$ne": "templates"}}
+        # This will return the mongo-backed modulestore 
+        # even if we're using a mixed modulestore
+        store = editable_modulestore()
 
-        # Remove everything except templates
-        modulestore.collection.remove(query)
-        modulestore.collection.drop()
+        if hasattr(store, 'collection'):
+            store.collection.drop()
 
     @classmethod
     def setUpClass(cls):
         """
-        Flush the mongo store and set up templates.
+        Delete the existing modulestores, causing them to be reloaded.
         """
-
-        # Use a uuid to differentiate
-        # the mongo collections on jenkins.
-        cls.orig_modulestore = copy.deepcopy(settings.MODULESTORE)
-        if 'direct' not in settings.MODULESTORE:
-            settings.MODULESTORE['direct'] = settings.MODULESTORE['default']
-
-        settings.MODULESTORE['default']['OPTIONS']['collection'] = 'modulestore_%s' % uuid4().hex
-        settings.MODULESTORE['direct']['OPTIONS']['collection'] = 'modulestore_%s' % uuid4().hex
-        xmodule.modulestore.django._MODULESTORES.clear()
-
-        print settings.MODULESTORE
-
+        # Clear out any existing modulestores,
+        # which will cause them to be re-created
+        # the next time they are accessed.
+        clear_existing_modulestores()
         TestCase.setUpClass()
 
     @classmethod
     def tearDownClass(cls):
         """
-        Revert to the old modulestore settings.
+        Drop the existing modulestores, causing them to be reloaded.
+        Clean up any data stored in Mongo.
         """
+        # Clean up by flushing the Mongo modulestore
+        cls.drop_mongo_collection()
 
-        # Clean up by dropping the collection
-        modulestore = xmodule.modulestore.django.modulestore()
-        modulestore.collection.drop()
+        # Clear out the existing modulestores,
+        # which will cause them to be re-created
+        # the next time they are accessed.
+        # We do this at *both* setup and teardown just to be safe.
+        clear_existing_modulestores()
 
-        xmodule.modulestore.django._MODULESTORES.clear()
-
-        # Restore the original modulestore settings
-        settings.MODULESTORE = cls.orig_modulestore
+        TestCase.tearDownClass()
 
     def _pre_setup(self):
         """
-        Remove everything but the templates before each test.
+        Flush the ModuleStore before each test.
         """
 
-        # Flush anything that is not a template
-        ModuleStoreTestCase.flush_mongo_except_templates()
+        # Flush the Mongo modulestore
+        ModuleStoreTestCase.drop_mongo_collection()
 
         # Call superclass implementation
         super(ModuleStoreTestCase, self)._pre_setup()
 
     def _post_teardown(self):
         """
-        Flush everything we created except the templates.
+        Flush the ModuleStore after each test.
         """
-        # Flush anything that is not a template
-        ModuleStoreTestCase.flush_mongo_except_templates()
+        ModuleStoreTestCase.drop_mongo_collection()
 
         # Call superclass implementation
         super(ModuleStoreTestCase, self)._post_teardown()
-
-
-    def assert2XX(self, status_code, msg=None):
-        """
-        Assert that the given value is a success status (between 200 and 299)
-        """
-        msg = self._formatMessage(msg, "%s is not a success status" % safe_repr(status_code))
-        self.assertTrue(status_code >= 200 and status_code < 300, msg=msg)
-
-    def assert3XX(self, status_code, msg=None):
-        """
-        Assert that the given value is a redirection status (between 300 and 399)
-        """
-        msg = self._formatMessage(msg, "%s is not a redirection status" % safe_repr(status_code))
-        self.assertTrue(status_code >= 300 and status_code < 400, msg=msg)
-
-    def assert4XX(self, status_code, msg=None):
-        """
-        Assert that the given value is a client error status (between 400 and 499)
-        """
-        msg = self._formatMessage(msg, "%s is not a client error status" % safe_repr(status_code))
-        self.assertTrue(status_code >= 400 and status_code < 500, msg=msg)
-
-    def assert5XX(self, status_code, msg=None):
-        """
-        Assert that the given value is a server error status (between 500 and 599)
-        """
-        msg = self._formatMessage(msg, "%s is not a server error status" % safe_repr(status_code))
-        self.assertTrue(status_code >= 500 and status_code < 600, msg=msg)
diff --git a/common/lib/xmodule/xmodule/modulestore/tests/factories.py b/common/lib/xmodule/xmodule/modulestore/tests/factories.py
index f2e4017114..7913434086 100644
--- a/common/lib/xmodule/xmodule/modulestore/tests/factories.py
+++ b/common/lib/xmodule/xmodule/modulestore/tests/factories.py
@@ -5,11 +5,12 @@ from uuid import uuid4
 from pytz import UTC
 
 from xmodule.modulestore import Location
-from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.django import editable_modulestore
 from xmodule.course_module import CourseDescriptor
 from xblock.core import Scope
 from xmodule.x_module import XModuleDescriptor
 
+
 class XModuleCourseFactory(Factory):
     """
     Factory for XModule courses.
@@ -25,10 +26,7 @@ class XModuleCourseFactory(Factory):
         display_name = kwargs.pop('display_name', None)
         location = Location('i4x', org, number, 'course', Location.clean(display_name))
 
-        try:
-            store = modulestore('direct')
-        except KeyError:
-            store = modulestore()
+        store = editable_modulestore('direct')
 
         # Write the data to the mongo datastore
         new_course = store.create_xmodule(location)
@@ -117,7 +115,7 @@ class XModuleItemFactory(Factory):
             if not isinstance(data, basestring):
                 data.update(template.get('data'))
 
-        store = modulestore('direct')
+        store = editable_modulestore('direct')
 
         # This code was based off that in cms/djangoapps/contentstore/views.py
         parent = store.get_item(parent_location)
diff --git a/lms/djangoapps/course_wiki/tests/tests.py b/lms/djangoapps/course_wiki/tests/tests.py
index 6bbd8011d6..93954dab61 100644
--- a/lms/djangoapps/course_wiki/tests/tests.py
+++ b/lms/djangoapps/course_wiki/tests/tests.py
@@ -3,21 +3,18 @@ from django.test.utils import override_settings
 
 import xmodule.modulestore.django
 
-from courseware.tests.tests import LoginEnrollmentTestCase, TEST_DATA_XML_MODULESTORE
+from courseware.tests.tests import LoginEnrollmentTestCase
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from xmodule.modulestore.django import modulestore
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class WikiRedirectTestCase(LoginEnrollmentTestCase):
+
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
-        courses = modulestore().get_courses()
 
-        def find_course(name):
-            """Assumes the course is present"""
-            return [c for c in courses if c.location.course == name][0]
-
-        self.toy = find_course("toy")
+        # Load the toy course
+        self.toy = modulestore().get_course('edX/toy/2012_Fall')
 
         # Create two accounts
         self.student = 'view@test.com'
diff --git a/lms/djangoapps/courseware/tests/__init__.py b/lms/djangoapps/courseware/tests/__init__.py
index 9d1b549b9f..4b93e804bf 100644
--- a/lms/djangoapps/courseware/tests/__init__.py
+++ b/lms/djangoapps/courseware/tests/__init__.py
@@ -12,7 +12,7 @@ from django.core.urlresolvers import reverse
 from django.test.client import Client
 
 from student.tests.factories import UserFactory, CourseEnrollmentFactory
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from xmodule.tests import get_test_system
 from xmodule.modulestore import Location
 from xmodule.modulestore.django import modulestore
@@ -20,7 +20,7 @@ from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class BaseTestXmodule(ModuleStoreTestCase):
     """Base class for testing Xmodules with mongo store.
 
diff --git a/lms/djangoapps/courseware/tests/modulestore_config.py b/lms/djangoapps/courseware/tests/modulestore_config.py
index 80a7b0a7c1..74fd3da57f 100644
--- a/lms/djangoapps/courseware/tests/modulestore_config.py
+++ b/lms/djangoapps/courseware/tests/modulestore_config.py
@@ -1,4 +1,10 @@
-from xmodule.modulestore.tests.django_utils import xml_store_config, mongo_store_config, draft_mongo_store_config
+"""
+Define test configuration for modulestores.
+"""
+
+from xmodule.modulestore.tests.django_utils import xml_store_config, \
+    mongo_store_config, draft_mongo_store_config,\
+    mixed_store_config
 
 from django.conf import settings
 
@@ -6,3 +12,15 @@ TEST_DATA_DIR = settings.COMMON_TEST_DATA_ROOT
 TEST_DATA_XML_MODULESTORE = xml_store_config(TEST_DATA_DIR)
 TEST_DATA_MONGO_MODULESTORE = mongo_store_config(TEST_DATA_DIR)
 TEST_DATA_DRAFT_MONGO_MODULESTORE = draft_mongo_store_config(TEST_DATA_DIR)
+
+# Map all XML course fixtures so they are accessible through
+# the MixedModuleStore
+MAPPINGS = {
+    'edX/toy/2012_Fall': 'xml',
+    'edX/toy/TT_2012_Fall': 'xml',
+    'edX/test_end/2012_Fall': 'xml',
+    'edX/test_about_blob_end_date/2012_Fall': 'xml',
+    'edX/graded/2012_Fall': 'xml',
+    'edX/open_ended/2012_Fall': 'xml',
+}
+TEST_DATA_MIXED_MODULESTORE = mixed_store_config(TEST_DATA_DIR, MAPPINGS)
diff --git a/lms/djangoapps/courseware/tests/test_masquerade.py b/lms/djangoapps/courseware/tests/test_masquerade.py
index 0fc4eae242..0ec320b605 100644
--- a/lms/djangoapps/courseware/tests/test_masquerade.py
+++ b/lms/djangoapps/courseware/tests/test_masquerade.py
@@ -15,23 +15,23 @@ from django.core.urlresolvers import reverse
 from django.contrib.auth.models import Group, User
 from courseware.access import _course_staff_group_name
 from courseware.tests.helpers import LoginEnrollmentTestCase
-from modulestore_config import TEST_DATA_XML_MODULESTORE
-from xmodule.modulestore.django import modulestore
-import xmodule.modulestore.django
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.django import modulestore, clear_existing_modulestores
 import json
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestStaffMasqueradeAsStudent(LoginEnrollmentTestCase):
-    '''
-    Check for staff being able to masquerade as student
-    '''
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestStaffMasqueradeAsStudent(ModuleStoreTestCase, LoginEnrollmentTestCase):
+    """
+    Check for staff being able to masquerade as student.
+    """
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
 
-        #self.full = modulestore().get_course("edX/full/6.002_Spring_2012")
-        #self.toy = modulestore().get_course("edX/toy/2012_Fall")
+        # Clear out the modulestores, causing them to reload
+        clear_existing_modulestores()
+
         self.graded_course = modulestore().get_course("edX/graded/2012_Fall")
 
         # Create staff account
@@ -50,7 +50,6 @@ class TestStaffMasqueradeAsStudent(LoginEnrollmentTestCase):
         self.logout()
         self.login(self.instructor, self.password)
         self.enroll(self.graded_course)
-        # self.factory = RequestFactory()
 
     def get_cw_section(self):
         url = reverse('courseware_section',
@@ -70,9 +69,9 @@ class TestStaffMasqueradeAsStudent(LoginEnrollmentTestCase):
         self.assertTrue(sdebug in resp.content)
 
     def toggle_masquerade(self):
-        '''
-        Toggle masquerade state
-        '''
+        """
+        Toggle masquerade state.
+        """
         masq_url = reverse('masquerade-switch', kwargs={'marg': 'toggle'})
         print "masq_url ", masq_url
         resp = self.client.get(masq_url)
diff --git a/lms/djangoapps/courseware/tests/test_module_render.py b/lms/djangoapps/courseware/tests/test_module_render.py
index 56659b7c2b..911136da77 100644
--- a/lms/djangoapps/courseware/tests/test_module_render.py
+++ b/lms/djangoapps/courseware/tests/test_module_render.py
@@ -15,22 +15,17 @@ from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.tests.factories import ItemFactory, CourseFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 import courseware.module_render as render
-from courseware.tests.tests import LoginEnrollmentTestCase, TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.tests import LoginEnrollmentTestCase
 from courseware.model_data import ModelDataCache
-from modulestore_config import TEST_DATA_XML_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 from courseware.courses import get_course_with_access, course_image_url, get_course_info_section
 
 from .factories import UserFactory
 
 
-class Stub:
-    def __init__(self):
-        pass
-
-
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class ModuleRenderTestCase(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class ModuleRenderTestCase(ModuleStoreTestCase, LoginEnrollmentTestCase):
     def setUp(self):
         self.location = ['i4x', 'edX', 'toy', 'chapter', 'Overview']
         self.course_id = 'edX/toy/2012_Fall'
@@ -96,7 +91,7 @@ class ModuleRenderTestCase(LoginEnrollmentTestCase):
                                       settings.MAX_FILEUPLOADS_PER_INPUT}))
         mock_request_2 = MagicMock()
         mock_request_2.FILES.keys.return_value = ['file_id']
-        inputfile = Stub()
+        inputfile = MagicMock()
         inputfile.size = 1 + settings.STUDENT_FILEUPLOAD_MAX_SIZE
         inputfile.name = 'name'
         filelist = [inputfile]
@@ -109,7 +104,7 @@ class ModuleRenderTestCase(LoginEnrollmentTestCase):
         mock_request_3.POST.copy.return_value = {'position': 1}
         mock_request_3.FILES = False
         mock_request_3.user = self.mock_user
-        inputfile_2 = Stub()
+        inputfile_2 = MagicMock()
         inputfile_2.size = 1
         inputfile_2.name = 'name'
         self.assertIsInstance(render.modx_dispatch(mock_request_3, 'goto_position',
@@ -200,7 +195,7 @@ class ModuleRenderTestCase(LoginEnrollmentTestCase):
         self.assertEquals(403, response.status_code)
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestTOC(TestCase):
     """Check the Table of Contents for a course"""
     def setUp(self):
@@ -266,7 +261,7 @@ class TestTOC(TestCase):
             self.assertIn(toc_section, actual)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestHtmlModifiers(ModuleStoreTestCase):
     """
     Tests to verify that standard modifications to the output of XModule/XBlock
diff --git a/lms/djangoapps/courseware/tests/test_navigation.py b/lms/djangoapps/courseware/tests/test_navigation.py
index dd1f00711c..2b416b16de 100644
--- a/lms/djangoapps/courseware/tests/test_navigation.py
+++ b/lms/djangoapps/courseware/tests/test_navigation.py
@@ -6,10 +6,10 @@ from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 from helpers import LoginEnrollmentTestCase, check_for_get_code
-from modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestNavigation(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Check that navigation state is saved properly.
diff --git a/lms/djangoapps/courseware/tests/test_submitting_problems.py b/lms/djangoapps/courseware/tests/test_submitting_problems.py
index 9081a910c9..f8cfaefd75 100644
--- a/lms/djangoapps/courseware/tests/test_submitting_problems.py
+++ b/lms/djangoapps/courseware/tests/test_submitting_problems.py
@@ -13,17 +13,17 @@ from django.test.utils import override_settings
 from courseware import grades
 from courseware.model_data import ModelDataCache
 
-from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.django import modulestore, editable_modulestore
 
 #import factories and parent testcase modules
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from capa.tests.response_xml_factory import OptionResponseXMLFactory, CustomResponseXMLFactory, SchematicResponseXMLFactory
 from courseware.tests.helpers import LoginEnrollmentTestCase
-from courseware.tests.modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestSubmittingProblems(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
         Check that a course gets graded properly.
@@ -217,7 +217,8 @@ class TestCourseGrader(TestSubmittingProblems):
         """
 
         course_data = {'grading_policy': grading_policy}
-        modulestore().update_item(self.course.location, course_data)
+        store = editable_modulestore('direct')
+        store.update_item(self.course.location, course_data)
         self.refresh_course()
 
     def get_grade_summary(self):
diff --git a/lms/djangoapps/courseware/tests/test_tabs.py b/lms/djangoapps/courseware/tests/test_tabs.py
index 4435b5c951..5de7a39f63 100644
--- a/lms/djangoapps/courseware/tests/test_tabs.py
+++ b/lms/djangoapps/courseware/tests/test_tabs.py
@@ -7,9 +7,9 @@ import courseware.tabs as tabs
 from django.test.utils import override_settings
 from django.core.urlresolvers import reverse
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 
 class ProgressTestCase(TestCase):
@@ -261,7 +261,7 @@ class ValidateTabsTestCase(TestCase):
         self.assertRaises(tabs.InvalidTabsException, tabs.validate_tabs, self.courses[4])
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class DiscussionLinkTestCase(ModuleStoreTestCase):
 
     def setUp(self):
diff --git a/lms/djangoapps/courseware/tests/test_view_authentication.py b/lms/djangoapps/courseware/tests/test_view_authentication.py
index 055c860fcc..849e5fdc45 100644
--- a/lms/djangoapps/courseware/tests/test_view_authentication.py
+++ b/lms/djangoapps/courseware/tests/test_view_authentication.py
@@ -16,10 +16,10 @@ from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 
 from helpers import LoginEnrollmentTestCase, check_for_get_code
-from modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestViewAuth(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Check that view authentication works properly.
diff --git a/lms/djangoapps/courseware/tests/test_views.py b/lms/djangoapps/courseware/tests/test_views.py
index 377ada11f5..c6c382c8e4 100644
--- a/lms/djangoapps/courseware/tests/test_views.py
+++ b/lms/djangoapps/courseware/tests/test_views.py
@@ -18,23 +18,21 @@ from xmodule.modulestore.django import modulestore
 import courseware.views as views
 from xmodule.modulestore import Location
 from pytz import UTC
-from modulestore_config import TEST_DATA_XML_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from course_modes.models import CourseMode
 
 
-class Stub():
-    pass
-
-
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestJumpTo(TestCase):
-    """Check the jumpto link for a course"""
-    def setUp(self):
-        self._MODULESTORES = {}
+    """
+        Check the jumpto link for a course.
+    """
 
-        # Toy courses should be loaded
+    def setUp(self):
+
+        # Load toy course from XML
         self.course_name = 'edX/toy/2012_Fall'
-        self.toy_course = modulestore().get_course('edX/toy/2012_Fall')
+        self.toy_course = modulestore().get_course(self.course_name)
 
     def test_jumpto_invalid_location(self):
         location = Location('i4x', 'edX', 'toy', 'NoSuchPlace', None)
@@ -73,7 +71,7 @@ class ViewsTestCase(TestCase):
         self.enrollment.created = self.date
         self.enrollment.save()
         self.location = ['tag', 'org', 'course', 'category', 'name']
-        self._MODULESTORES = {}
+
         # This is a CourseDescriptor object
         self.toy_course = modulestore().get_course('edX/toy/2012_Fall')
         self.request_factory = RequestFactory()
@@ -87,7 +85,7 @@ class ViewsTestCase(TestCase):
         self.assertEquals(views.user_groups(mock_user), [])
 
     def test_get_current_child(self):
-        self.assertIsNone(views.get_current_child(Stub()))
+        self.assertIsNone(views.get_current_child(MagicMock()))
         mock_xmodule = MagicMock()
         mock_xmodule.position = -1
         mock_xmodule.get_display_items.return_value = ['one', 'two']
diff --git a/lms/djangoapps/courseware/tests/tests.py b/lms/djangoapps/courseware/tests/tests.py
index 68b06a1ba8..98bcba4ed0 100644
--- a/lms/djangoapps/courseware/tests/tests.py
+++ b/lms/djangoapps/courseware/tests/tests.py
@@ -1,25 +1,20 @@
-'''
-Test for lms courseware app
-'''
-import random
-
-from django.test import TestCase
+"""
+Test for LMS courseware app.
+"""
 from django.core.urlresolvers import reverse
 from django.test.utils import override_settings
 
-import xmodule.modulestore.django
 from xmodule.error_module import ErrorDescriptor
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore import Location
 from xmodule.modulestore.xml_importer import import_from_xml
-from xmodule.modulestore.xml import XMLModuleStore
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
-from helpers import LoginEnrollmentTestCase
-from modulestore_config import TEST_DATA_DIR, \
-    TEST_DATA_XML_MODULESTORE, \
+from courseware.tests.helpers import LoginEnrollmentTestCase
+from courseware.tests.modulestore_config import TEST_DATA_DIR, \
     TEST_DATA_MONGO_MODULESTORE, \
-    TEST_DATA_DRAFT_MONGO_MODULESTORE
-import xmodule
+    TEST_DATA_DRAFT_MONGO_MODULESTORE, \
+    TEST_DATA_MIXED_MODULESTORE
 
 
 class ActivateLoginTest(LoginEnrollmentTestCase):
@@ -47,57 +42,60 @@ class PageLoaderTestCase(LoginEnrollmentTestCase):
     Base class that adds a function to load all pages in a modulestore.
     """
 
-    def check_random_page_loads(self, module_store):
+    def check_all_pages_load(self, course_id):
         """
-        Choose a page in the course randomly, and assert that it loads.
+        Assert that all pages in the course load correctly.
+        `course_id` is the ID of the course to check.
         """
-        # enroll in the course before trying to access pages
-        courses = module_store.get_courses()
-        self.assertEqual(len(courses), 1)
-        course = courses[0]
+
+        store = modulestore()
+
+        # Enroll in the course before trying to access pages
+        course = store.get_course(course_id)
         self.enroll(course, True)
-        course_id = course.id
 
         # Search for items in the course
         # None is treated as a wildcard
         course_loc = course.location
-        location_query = Location(course_loc.tag, course_loc.org,
-                                  course_loc.course, None, None, None)
+        location_query = Location(
+            course_loc.tag, course_loc.org,
+            course_loc.course, None, None, None
+        )
 
-        items = module_store.get_items(location_query, course_id=course_id)
+        items = store.get_items(
+            location_query,
+            course_id=course_id,
+            depth=2
+        )
 
         if len(items) < 1:
             self.fail('Could not retrieve any items from course')
-        else:
-            descriptor = random.choice(items)
 
-        # We have ancillary course information now as modules
-        # and we can't simply use 'jump_to' to view them
-        if descriptor.location.category == 'about':
-            self._assert_loads('about_course',
-                               {'course_id': course_id},
-                               descriptor)
+        # Try to load each item in the course
+        for descriptor in items:
 
-        elif descriptor.location.category == 'static_tab':
-            kwargs = {'course_id': course_id,
-                      'tab_slug': descriptor.location.name}
-            self._assert_loads('static_tab', kwargs, descriptor)
+            if descriptor.location.category == 'about':
+                self._assert_loads('about_course',
+                                   {'course_id': course_id},
+                                   descriptor)
 
-        elif descriptor.location.category == 'course_info':
-            self._assert_loads('info', {'course_id': course_id},
-                               descriptor)
+            elif descriptor.location.category == 'static_tab':
+                kwargs = {'course_id': course_id,
+                          'tab_slug': descriptor.location.name}
+                self._assert_loads('static_tab', kwargs, descriptor)
 
-        elif descriptor.location.category == 'custom_tag_template':
-            pass
+            elif descriptor.location.category == 'course_info':
+                self._assert_loads('info', {'course_id': course_id},
+                                   descriptor)
 
-        else:
+            else:
 
-            kwargs = {'course_id': course_id,
-                      'location': descriptor.location.url()}
+                kwargs = {'course_id': course_id,
+                          'location': descriptor.location.url()}
 
-            self._assert_loads('jump_to', kwargs, descriptor,
-                               expect_redirect=True,
-                               check_content=True)
+                self._assert_loads('jump_to', kwargs, descriptor,
+                                   expect_redirect=True,
+                                   check_content=True)
 
     def _assert_loads(self, django_url, kwargs, descriptor,
                       expect_redirect=False,
@@ -124,54 +122,51 @@ class PageLoaderTestCase(LoginEnrollmentTestCase):
             self.assertNotIsInstance(descriptor, ErrorDescriptor)
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestCoursesLoadTestCase_XmlModulestore(PageLoaderTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestXmlCoursesLoad(ModuleStoreTestCase, PageLoaderTestCase):
     """
     Check that all pages in test courses load properly from XML.
     """
 
     def setUp(self):
-        super(TestCoursesLoadTestCase_XmlModulestore, self).setUp()
+        super(TestXmlCoursesLoad, self).setUp()
         self.setup_user()
-        xmodule.modulestore.django._MODULESTORES.clear()
 
     def test_toy_course_loads(self):
-        module_class = 'xmodule.hidden_module.HiddenDescriptor'
-        module_store = XMLModuleStore(TEST_DATA_DIR,
-                                      default_class=module_class,
-                                      course_dirs=['toy'],
-                                      load_error_modules=True)
 
-        self.check_random_page_loads(module_store)
+        # Load one of the XML based courses
+        # Our test mapping rules allow the MixedModuleStore
+        # to load this course from XML, not Mongo.
+        self.check_all_pages_load('edX/toy/2012_Fall')
 
 
+# Importing XML courses isn't possible with MixedModuleStore,
+# so we use a Mongo modulestore directly (as we would in Studio)
 @override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
-class TestCoursesLoadTestCase_MongoModulestore(PageLoaderTestCase):
+class TestMongoCoursesLoad(ModuleStoreTestCase, PageLoaderTestCase):
     """
     Check that all pages in test courses load properly from Mongo.
     """
 
     def setUp(self):
-        super(TestCoursesLoadTestCase_MongoModulestore, self).setUp()
+        super(TestMongoCoursesLoad, self).setUp()
         self.setup_user()
-        xmodule.modulestore.django._MODULESTORES.clear()
-        modulestore().collection.drop()
+
+        # Import the toy course into a Mongo-backed modulestore
+        self.store = modulestore()
+        import_from_xml(self.store, TEST_DATA_DIR, ['toy'])
 
     def test_toy_course_loads(self):
-        module_store = modulestore()
-        import_from_xml(module_store, TEST_DATA_DIR, ['toy'])
-        self.check_random_page_loads(module_store)
+        self.check_all_pages_load('edX/toy/2012_Fall')
 
     def test_toy_textbooks_loads(self):
-        module_store = modulestore()
-        import_from_xml(module_store, TEST_DATA_DIR, ['toy'])
-
-        course = module_store.get_item(Location(['i4x', 'edX', 'toy', 'course', '2012_Fall', None]))
-
+        location = Location(['i4x', 'edX', 'toy', 'course', '2012_Fall', None])
+        course = self.store.get_item(location)
         self.assertGreater(len(course.textbooks), 0)
 
+
 @override_settings(MODULESTORE=TEST_DATA_DRAFT_MONGO_MODULESTORE)
-class TestDraftModuleStore(TestCase):
+class TestDraftModuleStore(ModuleStoreTestCase):
     def test_get_items_with_course_items(self):
         store = modulestore()
 
diff --git a/lms/djangoapps/django_comment_client/base/tests.py b/lms/djangoapps/django_comment_client/base/tests.py
index 434d4d616b..e6ce3b2d25 100644
--- a/lms/djangoapps/django_comment_client/base/tests.py
+++ b/lms/djangoapps/django_comment_client/base/tests.py
@@ -10,14 +10,14 @@ from django.core.urlresolvers import reverse
 from django.core.management import call_command
 from util.testing import UrlResetMixin
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from nose.tools import assert_true, assert_equal
 from mock import patch
 
 log = logging.getLogger(__name__)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 @patch('comment_client.utils.requests.request')
 class ViewsTestCase(UrlResetMixin, ModuleStoreTestCase):
 
diff --git a/lms/djangoapps/django_comment_client/forum/tests.py b/lms/djangoapps/django_comment_client/forum/tests.py
index bd18ab80d6..2d889722a4 100644
--- a/lms/djangoapps/django_comment_client/forum/tests.py
+++ b/lms/djangoapps/django_comment_client/forum/tests.py
@@ -6,7 +6,7 @@ from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from django.core.urlresolvers import reverse
 from util.testing import UrlResetMixin
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from nose.tools import assert_true
 from mock import patch, Mock
 
@@ -15,7 +15,7 @@ import logging
 log = logging.getLogger(__name__)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class ViewsExceptionTestCase(UrlResetMixin, ModuleStoreTestCase):
 
     @patch.dict("django.conf.settings.MITX_FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
diff --git a/lms/djangoapps/instructor/tests/test_access.py b/lms/djangoapps/instructor/tests/test_access.py
index 688ed89dad..1874e88f22 100644
--- a/lms/djangoapps/instructor/tests/test_access.py
+++ b/lms/djangoapps/instructor/tests/test_access.py
@@ -9,7 +9,7 @@ from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 from django.test.utils import override_settings
-from courseware.tests.modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 from courseware.access import get_access_group_name
 from django_comment_common.models import (Role,
@@ -20,7 +20,7 @@ from instructor.access import (allow_access,
                                update_forum_role_membership)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAccessList(ModuleStoreTestCase):
     """ Test access listings. """
     def setUp(self):
@@ -42,7 +42,7 @@ class TestInstructorAccessList(ModuleStoreTestCase):
         self.assertEqual(set(beta_testers), set(self.beta_testers))
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAccessAllow(ModuleStoreTestCase):
     """ Test access allow. """
     def setUp(self):
@@ -85,7 +85,8 @@ class TestInstructorAccessAllow(ModuleStoreTestCase):
         group = Group.objects.get(name=get_access_group_name(self.course, 'staff'))
         self.assertIn(user, group.user_set.all())
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAccessRevoke(ModuleStoreTestCase):
     """ Test access revoke. """
     def setUp(self):
@@ -129,7 +130,7 @@ class TestInstructorAccessRevoke(ModuleStoreTestCase):
         self.assertNotIn(user, group.user_set.all())
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAccessForum(ModuleStoreTestCase):
     """
     Test forum access control.
diff --git a/lms/djangoapps/instructor/tests/test_api.py b/lms/djangoapps/instructor/tests/test_api.py
index 155a8a2c9f..7d55b001d0 100644
--- a/lms/djangoapps/instructor/tests/test_api.py
+++ b/lms/djangoapps/instructor/tests/test_api.py
@@ -14,7 +14,7 @@ from django.core.urlresolvers import reverse
 from django.http import HttpRequest, HttpResponse
 
 from django.contrib.auth.models import User
-from courseware.tests.modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from courseware.tests.helpers import LoginEnrollmentTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
@@ -90,7 +90,7 @@ class TestCommonExceptions400(unittest.TestCase):
         self.assertIn("Task is already running", result["error"])
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPIDenyLevels(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Ensure that users cannot access endpoints they shouldn't be able to.
@@ -147,7 +147,7 @@ class TestInstructorAPIDenyLevels(ModuleStoreTestCase, LoginEnrollmentTestCase):
             self.assertEqual(response.status_code, 403)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPIEnrollment(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Test enrollment modification endpoint.
@@ -270,7 +270,7 @@ class TestInstructorAPIEnrollment(ModuleStoreTestCase, LoginEnrollmentTestCase):
         self.assertEqual(res_json, expected)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPILevelsAccess(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Test endpoints whereby instructors can change permissions
@@ -414,7 +414,7 @@ class TestInstructorAPILevelsAccess(ModuleStoreTestCase, LoginEnrollmentTestCase
         self.assertEqual(res_json, expected)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPILevelsDataDump(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Test endpoints that show data without side effects.
@@ -521,7 +521,7 @@ class TestInstructorAPILevelsDataDump(ModuleStoreTestCase, LoginEnrollmentTestCa
         self.assertEqual(response.status_code, 400)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPIRegradeTask(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Test endpoints whereby instructors can change student grades.
@@ -655,7 +655,7 @@ class TestInstructorAPIRegradeTask(ModuleStoreTestCase, LoginEnrollmentTestCase)
         self.assertTrue(act.called)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorAPITaskLists(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Test instructor task list endpoint.
@@ -745,7 +745,7 @@ class TestInstructorAPITaskLists(ModuleStoreTestCase, LoginEnrollmentTestCase):
         self.assertEqual(json.loads(response.content), expected_res)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 @override_settings(ANALYTICS_SERVER_URL="http://robotanalyticsserver.netbot:900/")
 @override_settings(ANALYTICS_API_KEY="robot_api_key")
 class TestInstructorAPIAnalyticsProxy(ModuleStoreTestCase, LoginEnrollmentTestCase):
diff --git a/lms/djangoapps/instructor/tests/test_hint_manager.py b/lms/djangoapps/instructor/tests/test_hint_manager.py
index 8e394d6e54..456f8e0ed8 100644
--- a/lms/djangoapps/instructor/tests/test_hint_manager.py
+++ b/lms/djangoapps/instructor/tests/test_hint_manager.py
@@ -5,14 +5,14 @@ from django.test.utils import override_settings
 
 from courseware.models import XModuleContentField
 from courseware.tests.factories import ContentFactory
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 import instructor.hint_manager as view
 from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class HintManagerTest(ModuleStoreTestCase):
 
     def setUp(self):
diff --git a/lms/djangoapps/instructor/tests/test_legacy_download_csv.py b/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
index b05746f015..c65547e408 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
@@ -17,21 +17,20 @@ from django.core.urlresolvers import reverse
 
 from courseware.access import _course_staff_group_name
 from courseware.tests.helpers import LoginEnrollmentTestCase
-from courseware.tests.modulestore_config import TEST_DATA_XML_MODULESTORE
-from xmodule.modulestore.django import modulestore
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.django import modulestore, clear_existing_modulestores
 import xmodule.modulestore.django
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestInstructorDashboardGradeDownloadCSV(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestInstructorDashboardGradeDownloadCSV(ModuleStoreTestCase, LoginEnrollmentTestCase):
     '''
     Check for download of csv
     '''
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
-
-        self.full = modulestore().get_course("edX/full/6.002_Spring_2012")
+        clear_existing_modulestores()
         self.toy = modulestore().get_course("edX/toy/2012_Fall")
 
         # Create two accounts
diff --git a/lms/djangoapps/instructor/tests/test_legacy_enrollment.py b/lms/djangoapps/instructor/tests/test_legacy_enrollment.py
index 1f5ea8ad56..4c1c252891 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_enrollment.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_enrollment.py
@@ -7,7 +7,7 @@ from django.test.utils import override_settings
 from django.contrib.auth.models import User
 from django.core.urlresolvers import reverse
 from courseware.tests.helpers import LoginEnrollmentTestCase
-from courseware.tests.modulestore_config import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from xmodule.modulestore.tests.factories import CourseFactory
 from student.tests.factories import UserFactory, CourseEnrollmentFactory, AdminFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
@@ -18,7 +18,7 @@ from django.core import mail
 USER_COUNT = 4
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestInstructorEnrollsStudent(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Check Enrollment/Unenrollment with/without auto-enrollment on activation and with/without email notification
diff --git a/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py b/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
index 90dadd569e..29046b151f 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
@@ -15,9 +15,9 @@ from django_comment_client.utils import has_forum_access
 
 from courseware.access import _course_staff_group_name
 from courseware.tests.helpers import LoginEnrollmentTestCase
-from courseware.tests.modulestore_config import TEST_DATA_XML_MODULESTORE
-from xmodule.modulestore.django import modulestore
-import xmodule.modulestore.django
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
+from xmodule.modulestore.django import modulestore, clear_existing_modulestores
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 
 FORUM_ROLES = [FORUM_ROLE_ADMINISTRATOR, FORUM_ROLE_MODERATOR, FORUM_ROLE_COMMUNITY_TA]
@@ -32,14 +32,14 @@ def action_name(operation, rolename):
         return '{0} forum {1}'.format(operation, FORUM_ADMIN_ACTION_SUFFIX[rolename])
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestInstructorDashboardForumAdmin(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestInstructorDashboardForumAdmin(ModuleStoreTestCase, LoginEnrollmentTestCase):
     '''
     Check for change in forum admin role memberships
     '''
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
+        clear_existing_modulestores()
         courses = modulestore().get_courses()
 
         self.course_id = "edX/toy/2012_Fall"
diff --git a/lms/djangoapps/instructor/tests/test_legacy_gradebook.py b/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
index aaf03deb8c..fd285d2e3f 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_gradebook.py
@@ -7,7 +7,7 @@ from django.core.urlresolvers import reverse
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from student.tests.factories import UserFactory, CourseEnrollmentFactory, AdminFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.tests import TEST_DATA_MIXED_MODULESTORE
 from capa.tests.response_xml_factory import StringResponseXMLFactory
 from courseware.tests.factories import StudentModuleFactory
 from xmodule.modulestore import Location
@@ -17,7 +17,7 @@ from xmodule.modulestore.django import modulestore
 USER_COUNT = 11
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestGradebook(ModuleStoreTestCase):
     grading_policy = None
 
diff --git a/lms/djangoapps/instructor/tests/test_legacy_xss.py b/lms/djangoapps/instructor/tests/test_legacy_xss.py
index 7df6511b3c..d748876032 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_xss.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_xss.py
@@ -7,14 +7,15 @@ from django.test.client import RequestFactory
 from django.test.utils import override_settings
 from markupsafe import escape
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.tests import TEST_DATA_MIXED_MODULESTORE
 from student.tests.factories import UserFactory, CourseEnrollmentFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
 from instructor.views import legacy
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class TestXss(ModuleStoreTestCase):
     def setUp(self):
         self._request_factory = RequestFactory()
diff --git a/lms/djangoapps/instructor_task/tests/test_base.py b/lms/djangoapps/instructor_task/tests/test_base.py
index b67453e997..2c1fe02bd8 100644
--- a/lms/djangoapps/instructor_task/tests/test_base.py
+++ b/lms/djangoapps/instructor_task/tests/test_base.py
@@ -13,13 +13,13 @@ from django.contrib.auth.models import User
 from django.test.utils import override_settings
 
 from capa.tests.response_xml_factory import OptionResponseXMLFactory
-from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.django import editable_modulestore
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 from student.tests.factories import CourseEnrollmentFactory, UserFactory
 from courseware.model_data import StudentModule
-from courseware.tests.tests import LoginEnrollmentTestCase, TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.tests import LoginEnrollmentTestCase, TEST_DATA_MIXED_MODULESTORE
 
 from instructor_task.api_helper import encode_problem_and_student_input
 from instructor_task.models import PROGRESS, QUEUING
@@ -95,7 +95,7 @@ class InstructorTaskTestCase(TestCase):
         return self._create_entry(task_state=task_state, task_output=progress, student=student)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class InstructorTaskModuleTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase):
     """
     Base test class for InstructorTask-related tests that require
@@ -106,7 +106,7 @@ class InstructorTaskModuleTestCase(LoginEnrollmentTestCase, ModuleStoreTestCase)
 
     def initialize_course(self):
         """Create a course in the store, with a chapter and section."""
-        self.module_store = modulestore()
+        self.module_store = editable_modulestore()
 
         # Create the course
         self.course = CourseFactory.create(org=TEST_COURSE_ORG,
diff --git a/lms/djangoapps/licenses/tests.py b/lms/djangoapps/licenses/tests.py
index 151a0faa9d..a853955c83 100644
--- a/lms/djangoapps/licenses/tests.py
+++ b/lms/djangoapps/licenses/tests.py
@@ -14,7 +14,7 @@ from django.core.management import call_command
 from django.core.urlresolvers import reverse
 from nose.tools import assert_true
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from licenses.models import CourseSoftware, UserLicense
 
 from student.tests.factories import UserFactory
@@ -143,7 +143,7 @@ class LicenseTestCase(TestCase):
         self.assertEqual(302, response.status_code)
 
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class CommandTest(ModuleStoreTestCase):
     '''Test management command for importing serial numbers'''
     def setUp(self):
diff --git a/lms/djangoapps/open_ended_grading/tests.py b/lms/djangoapps/open_ended_grading/tests.py
index 262124d667..7ae5994dc1 100644
--- a/lms/djangoapps/open_ended_grading/tests.py
+++ b/lms/djangoapps/open_ended_grading/tests.py
@@ -27,14 +27,15 @@ log = logging.getLogger(__name__)
 from django.test.utils import override_settings
 
 from xmodule.tests import test_util_open_ended
+from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 
 from courseware.tests import factories
-from courseware.tests.modulestore_config import TEST_DATA_XML_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from courseware.tests.helpers import LoginEnrollmentTestCase, check_for_get_code, check_for_post_code
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestStaffGradingService(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestStaffGradingService(ModuleStoreTestCase, LoginEnrollmentTestCase):
     '''
     Check that staff grading service proxy works.  Basically just checking the
     access control and error handling logic -- all the actual work is on the
@@ -42,8 +43,6 @@ class TestStaffGradingService(LoginEnrollmentTestCase):
     '''
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
-
         self.student = 'view@test.com'
         self.instructor = 'view2@test.com'
         self.password = 'foo'
@@ -138,8 +137,8 @@ class TestStaffGradingService(LoginEnrollmentTestCase):
         self.assertIsNotNone(content['problem_list'])
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestPeerGradingService(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestPeerGradingService(ModuleStoreTestCase, LoginEnrollmentTestCase):
     '''
     Check that staff grading service proxy works.  Basically just checking the
     access control and error handling logic -- all the actual work is on the
@@ -147,8 +146,6 @@ class TestPeerGradingService(LoginEnrollmentTestCase):
     '''
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
-
         self.student = 'view@test.com'
         self.instructor = 'view2@test.com'
         self.password = 'foo'
@@ -293,8 +290,8 @@ class TestPeerGradingService(LoginEnrollmentTestCase):
         self.assertFalse('actual_score' in response)
 
 
-@override_settings(MODULESTORE=TEST_DATA_XML_MODULESTORE)
-class TestPanel(LoginEnrollmentTestCase):
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
+class TestPanel(ModuleStoreTestCase, LoginEnrollmentTestCase):
     """
     Run tests on the open ended panel
     """
diff --git a/lms/djangoapps/staticbook/tests.py b/lms/djangoapps/staticbook/tests.py
index deb13ffc9e..135150a2d1 100644
--- a/lms/djangoapps/staticbook/tests.py
+++ b/lms/djangoapps/staticbook/tests.py
@@ -10,7 +10,7 @@ import requests
 from django.test.utils import override_settings
 from django.core.urlresolvers import reverse, NoReverseMatch
 
-from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
+from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 from student.tests.factories import UserFactory, CourseEnrollmentFactory
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
@@ -36,7 +36,8 @@ HTML_BOOK = {
     ],
 }
 
-@override_settings(MODULESTORE=TEST_DATA_MONGO_MODULESTORE)
+
+@override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
 class StaticBookTest(ModuleStoreTestCase):
     """
     Helpers for the static book tests.
diff --git a/lms/envs/acceptance.py b/lms/envs/acceptance.py
index cf64404161..e866a250d9 100644
--- a/lms/envs/acceptance.py
+++ b/lms/envs/acceptance.py
@@ -36,15 +36,21 @@ modulestore_options = {
 
 MODULESTORE = {
     'default': {
-        'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',
-        'OPTIONS': modulestore_options
-    },
-    'direct': {
-        'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',
-        'OPTIONS': modulestore_options
+        'ENGINE': 'xmodule.modulestore.mixed.MixedModuleStore',
+        'OPTIONS': {
+            'mappings': {},
+            'stores': {
+                'default': {
+                    'ENGINE': 'xmodule.modulestore.mongo.MongoModuleStore',
+                    'OPTIONS': modulestore_options
+                }
+            }
+        }
     }
 }
 
+MODULESTORE['direct'] = MODULESTORE['default']
+
 CONTENTSTORE = {
     'ENGINE': 'xmodule.contentstore.mongo.MongoContentStore',
     'OPTIONS': {