diff --git a/common/djangoapps/external_auth/tests/test_shib.py b/common/djangoapps/external_auth/tests/test_shib.py
index d48948c6ae..0355730256 100644
--- a/common/djangoapps/external_auth/tests/test_shib.py
+++ b/common/djangoapps/external_auth/tests/test_shib.py
@@ -14,12 +14,10 @@ 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 editable_modulestore
 
-from courseware.tests.modulestore_config import TEST_DATA_MIXED_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
diff --git a/lms/djangoapps/instructor/tests/test_hint_manager.py b/lms/djangoapps/instructor/tests/test_hint_manager.py
index 3b124f1c99..456f8e0ed8 100644
--- a/lms/djangoapps/instructor/tests/test_hint_manager.py
+++ b/lms/djangoapps/instructor/tests/test_hint_manager.py
@@ -5,7 +5,7 @@ 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_MIXED_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
diff --git a/lms/djangoapps/instructor/tests/test_legacy_download_csv.py b/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
index b77626c8a1..c65547e408 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_download_csv.py
@@ -18,19 +18,19 @@ 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_MIXED_MODULESTORE
-from xmodule.modulestore.django import 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_MIXED_MODULESTORE)
-class TestInstructorDashboardGradeDownloadCSV(LoginEnrollmentTestCase):
+class TestInstructorDashboardGradeDownloadCSV(ModuleStoreTestCase, LoginEnrollmentTestCase):
     '''
     Check for download of csv
     '''
 
     def setUp(self):
-        xmodule.modulestore.django._MODULESTORES = {}
-
+        clear_existing_modulestores()
         self.toy = modulestore().get_course("edX/toy/2012_Fall")
 
         # Create two accounts
diff --git a/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py b/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
index 3b691aa708..29046b151f 100644
--- a/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
+++ b/lms/djangoapps/instructor/tests/test_legacy_forum_admin.py
@@ -16,8 +16,8 @@ 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_MIXED_MODULESTORE
-from xmodule.modulestore.django import modulestore
-import xmodule.modulestore.django
+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]
@@ -33,13 +33,13 @@ def action_name(operation, rolename):
 
 
 @override_settings(MODULESTORE=TEST_DATA_MIXED_MODULESTORE)
-class TestInstructorDashboardForumAdmin(LoginEnrollmentTestCase):
+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"