Return empty values and log a warning instead of raising NotImplemented

exceptions for XML modulestore asset metadata methods.

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -285,7 +285,8 @@ class ModuleStoreAssetInterface(object):
         Returns the container holding a dict indexed by asset block_type whose values are a list
         of raw metadata documents
         """
-        raise NotImplementedError()
+        log.warning("_find_course_assets request of ModuleStoreAssetInterface - not implemented.")
+        return None
 
     def _find_course_asset(self, asset_key):
         """

common/lib/xmodule/xmodule/modulestore/tests/test_assetstore.py

@@ -455,14 +455,10 @@ class TestMongoAssetMetadataStorage(unittest.TestCase):
         with storebuilder.build(None) as store:
             course_key = store.make_course_key("org", "course", "run")
             asset_key = course_key.make_asset_key('asset', 'foo.jpg')
-            for method in ['find_asset_metadata']:
-                with self.assertRaises(NotImplementedError):
-                    getattr(store, method)(asset_key)
-            with self.assertRaises(NotImplementedError):
-                # pylint: disable=protected-access
-                store._find_course_asset(asset_key)
-            with self.assertRaises(NotImplementedError):
-                store.get_all_asset_metadata(course_key, 'asset')
+            self.assertEquals(store.find_asset_metadata(asset_key), None)
+            # pylint: disable=protected-access
+            self.assertEquals(store._find_course_asset(asset_key), (None, None))
+            self.assertEquals(store.get_all_asset_metadata(course_key, 'asset'), [])
 
     @ddt.data(*MODULESTORE_SETUPS)
     def test_copy_all_assets_same_modulestore(self, storebuilder):

common/lib/xmodule/xmodule/modulestore/xml.py

@@ -867,18 +867,21 @@ class XMLModuleStore(ModuleStoreReadBase):
         For now this is not implemented, but others should feel free to implement using the asset.json
         which export produces.
         """
-        raise NotImplementedError()
+        log.warning("_find_course_asset request of XML modulestore - not implemented.")
+        return (None, None)
 
     def find_asset_metadata(self, asset_key, **kwargs):
         """
         For now this is not implemented, but others should feel free to implement using the asset.json
         which export produces.
         """
-        raise NotImplementedError()
+        log.warning("find_asset_metadata request of XML modulestore - not implemented.")
+        return None
 
     def get_all_asset_metadata(self, course_key, asset_type, start=0, maxresults=-1, sort=None, **kwargs):
         """
         For now this is not implemented, but others should feel free to implement using the asset.json
         which export produces.
         """
-        raise NotImplementedError()
+        log.warning("get_all_asset_metadata request of XML modulestore - not implemented.")
+        return []