diff --git a/cms/djangoapps/contentstore/tests/test_import.py b/cms/djangoapps/contentstore/tests/test_import.py
index 5d063ce3dd..71db964448 100644
--- a/cms/djangoapps/contentstore/tests/test_import.py
+++ b/cms/djangoapps/contentstore/tests/test_import.py
@@ -14,7 +14,8 @@ from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from xmodule.contentstore.django import contentstore
-from xmodule.modulestore.tests.factories import check_exact_number_of_calls, check_number_of_calls
+from xmodule.modulestore.exceptions import DuplicateCourseError
+from xmodule.modulestore.tests.factories import check_exact_number_of_calls, check_number_of_calls, CourseFactory
 from opaque_keys.edx.locations import SlashSeparatedCourseKey, AssetLocation
 from xmodule.modulestore.xml_importer import import_from_xml
 from xmodule.exceptions import NotFoundError
diff --git a/common/lib/xmodule/xmodule/modulestore/split_mongo/split_draft.py b/common/lib/xmodule/xmodule/modulestore/split_mongo/split_draft.py
index d9b501f7bd..0dc859a796 100644
--- a/common/lib/xmodule/xmodule/modulestore/split_mongo/split_draft.py
+++ b/common/lib/xmodule/xmodule/modulestore/split_mongo/split_draft.py
@@ -297,4 +297,3 @@ class DraftVersioningModuleStore(ModuleStoreDraftAndPublished, SplitMongoModuleS
         Return the version of the given database representation of a block.
         """
         return block['edit_info'].get('source_version', block['edit_info']['update_version'])
-
diff --git a/common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py b/common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py
index 4af5fb5cd9..521615e0f9 100644
--- a/common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py
+++ b/common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py
@@ -544,6 +544,13 @@ class TestMixedModuleStore(unittest.TestCase):
         self.assertIn(self.course_locations[self.XML_COURSEID1], course_ids)
         self.assertIn(self.course_locations[self.XML_COURSEID2], course_ids)
 
+        with self.store.branch_setting(ModuleStoreEnum.Branch.draft_preferred):
+            draft_courses = self.store.get_courses(remove_branch=True)
+        with self.store.branch_setting(ModuleStoreEnum.Branch.published_only):
+            published_courses = self.store.get_courses(remove_branch=True)
+        self.assertEquals([c.id for c in draft_courses], [c.id for c in published_courses])
+
+
     def test_xml_get_courses(self):
         """
         Test that the xml modulestore only loaded the courses from the maps.
@@ -1229,7 +1236,7 @@ class TestMixedModuleStore(unittest.TestCase):
         with self.store.default_store(default_ms):
             self.verify_default_store(default_ms)
 
-    def test_nested_default_store(self):
+    def test_default_store_nested(self):
         """
         Test the default store context manager, nested within one another
         """
@@ -1245,6 +1252,17 @@ class TestMixedModuleStore(unittest.TestCase):
                 self.verify_default_store(ModuleStoreEnum.Type.split)
             self.verify_default_store(ModuleStoreEnum.Type.mongo)
 
+    def test_default_store_fake(self):
+        """
+        Test the default store context manager, asking for a fake store
+        """
+        # initialize the mixed modulestore
+        self._initialize_mixed()
+
+        fake_store = "fake"
+        with self.assertRaisesRegexp(Exception, "Cannot find store of type {}".format(fake_store)):
+            with self.store.default_store(fake_store):
+                pass  # pragma: no cover
 
 #=============================================================================================================
 # General utils for not using django settings
diff --git a/common/lib/xmodule/xmodule/modulestore/xml_importer.py b/common/lib/xmodule/xmodule/modulestore/xml_importer.py
index 66a3bf4dc0..f7bdd97091 100644
--- a/common/lib/xmodule/xmodule/modulestore/xml_importer.py
+++ b/common/lib/xmodule/xmodule/modulestore/xml_importer.py
@@ -176,6 +176,7 @@ def import_from_xml(
                     store.create_course(dest_course_id.org, dest_course_id.course, dest_course_id.run, user_id)
                 except DuplicateCourseError:
                     # course w/ same org and course exists
+                    # The Mongo modulestore checks *with* the run in has_course, but not in create_course.
                     log.debug(
                         "Skipping import of course with id, {0},"
                         "since it collides with an existing one".format(dest_course_id)