Fix modulestore merge conflict with heartbeat.

common/djangoapps/heartbeat/tests/test_heartbeat.py

@@ -6,14 +6,8 @@ from django.core.urlresolvers import reverse
 import json
 from django.db.utils import DatabaseError
 import mock
-from django.test.utils import override_settings
-from django.conf import settings
 from django.test.testcases import TestCase
-from xmodule.modulestore.tests.django_utils import draft_mongo_store_config
 
-TEST_MODULESTORE = draft_mongo_store_config(settings.TEST_ROOT / "data")
-
-@override_settings(MODULESTORE=TEST_MODULESTORE)
 class HeartbeatTestCase(TestCase):
     """
     Test the heartbeat

common/lib/xmodule/xmodule/modulestore/mixed.py

@@ -400,7 +400,7 @@ class MixedModuleStore(ModuleStoreWriteBase):
         return dict(
             itertools.chain.from_iterable(
                 store.heartbeat().iteritems()
-                for store in self.modulestores.itervalues()
+                for store in self.modulestores
             )
         )