add unit test to verify that the store updated signal actually fired. Also fix bug where cloning item doesn't update the inherited metadata caches

cms/djangoapps/contentstore/tests/test_contentstore.py

@@ -13,6 +13,7 @@ import copy
 from json import loads
 
 from django.contrib.auth.models import User
+from django.dispatch import Signal
 from contentstore.utils import get_modulestore
 
 from .utils import ModuleStoreTestCase, parse_json
@@ -591,6 +592,32 @@ class ContentStoreTest(ModuleStoreTestCase):
 
         self.assertNotEquals(new_discussion_item.discussion_id, '$$GUID$$')
 
+    def test_update_modulestore_signal_did_fire(self):
+
+        import_from_xml(modulestore(), 'common/test/data/', ['full'])
+        module_store = modulestore('direct')
+
+        try:
+            module_store.modulestore_update_signal = Signal(providing_args=['modulestore', 'course_id', 'location'])
+
+            self.got_signal = False
+
+            def _signal_hander(modulestore=None, course_id=None, location=None, **kwargs):
+                self.got_signal = True
+
+            module_store.modulestore_update_signal.connect(_signal_hander)
+
+            new_component_location = Location('i4x', 'edX', 'full', 'html', 'new_component')
+            source_template_location = Location('i4x', 'edx', 'templates', 'html', 'Blank_HTML_Page')
+
+            # crate a new module
+            module_store.clone_item(source_template_location, new_component_location)
+
+        finally:
+            module_store.modulestore_update_signal = None
+
+        self.assertTrue(self.got_signal)
+
     def test_metadata_inheritance(self):
         import_from_xml(modulestore(), 'common/test/data/', ['full'])
 

common/lib/xmodule/xmodule/modulestore/mongo.py

@@ -537,6 +537,7 @@ class MongoModuleStore(ModuleStoreBase):
         Clone a new item that is a copy of the item at the location `source`
         and writes it to `location`
         """
+        item = None
         try:
             source_item = self.collection.find_one(location_to_query(source))
 
@@ -568,7 +569,6 @@ class MongoModuleStore(ModuleStoreBase):
                 course.tabs = existing_tabs
                 self.update_metadata(course.location, course._model_data._kvs._metadata)
 
-            return item
         except pymongo.errors.DuplicateKeyError:
             raise DuplicateItemError(location)
 
@@ -576,6 +576,8 @@ class MongoModuleStore(ModuleStoreBase):
         self.refresh_cached_metadata_inheritance_tree(Location(location))
         self.fire_updated_modulestore_signal(get_course_id_no_run(Location(location)), Location(location))
 
+        return item
+
     def fire_updated_modulestore_signal(self, course_id, location):
         if self.modulestore_update_signal is not None:
             self.modulestore_update_signal.send(self, modulestore=self, course_id=course_id,