Abstract asset methods into own interface class

then impl the read ones as NotImplementedError placeholders on xml modulestore
PLAT-70

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

@@ -12,7 +12,7 @@ from xmodule.modulestore import ModuleStoreEnum
 
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.tests.test_cross_modulestore_import_export import (
-    MODULESTORE_SETUPS, MongoContentstoreBuilder,
+    MODULESTORE_SETUPS, MongoContentstoreBuilder, XmlModulestoreBuilder, MixedModulestoreBuilder
 )
 
 
@@ -392,3 +392,21 @@ class TestMongoAssetMetadataStorage(unittest.TestCase):
 
     def test_copy_all_assets(self):
         pass
+
+    @ddt.data(XmlModulestoreBuilder(), MixedModulestoreBuilder([('xml', XmlModulestoreBuilder())]))
+    def test_xml_not_yet_implemented(self, storebuilder):
+        """
+        Test coverage which shows that for now xml read operations are not implemented
+        """
+        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_info', 'find_asset_metadata', 'find_asset_thumbnail_metadata']:
+                with self.assertRaises(NotImplementedError):
+                    getattr(store, method)(asset_key)
+            with self.assertRaises(NotImplementedError):
+                # pylint: disable=protected-access
+                store._find_course_asset(course_key, asset_key.block_id)
+            for method in ['_get_all_asset_metadata', 'get_all_asset_metadata', 'get_all_asset_thumbnail_metadata']:
+                with self.assertRaises(NotImplementedError):
+                    getattr(store, method)(course_key)

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

@@ -17,6 +17,7 @@ import random
 from contextlib import contextmanager, nested
 from shutil import rmtree
 from tempfile import mkdtemp
+from path import path
 
 from xmodule.tests import CourseComparisonTest
 
@@ -30,13 +31,14 @@ from xmodule.modulestore.split_mongo.split_draft import DraftVersioningModuleSto
 from xmodule.modulestore.tests.mongo_connection import MONGO_PORT_NUM, MONGO_HOST
 from xmodule.modulestore.inheritance import InheritanceMixin
 from xmodule.x_module import XModuleMixin
+from xmodule.modulestore.xml import XMLModuleStore
 
 
 COMMON_DOCSTORE_CONFIG = {
     'host': MONGO_HOST,
     'port': MONGO_PORT_NUM,
 }
-
+DATA_DIR = path(__file__).dirname().parent.parent.parent.parent.parent / "test" / "data"
 
 XBLOCK_MIXINS = (InheritanceMixin, XModuleMixin)
 
@@ -163,6 +165,30 @@ class VersioningModulestoreBuilder(object):
         return 'SplitModulestoreBuilder()'
 
 
+class XmlModulestoreBuilder(object):
+    """
+    A builder class for a XMLModuleStore.
+    """
+    # pylint: disable=unused-argument
+    @contextmanager
+    def build(self, contentstore=None, course_ids=None):
+        """
+        A contextmanager that returns an isolated xml modulestore
+
+        Args:
+            contentstore: The contentstore that this modulestore should use to store
+                all of its assets.
+        """
+        modulestore = XMLModuleStore(
+            DATA_DIR,
+            course_ids=course_ids,
+            default_class='xmodule.hidden_module.HiddenDescriptor',
+            xblock_mixins=XBLOCK_MIXINS,
+        )
+
+        yield modulestore
+
+
 class MixedModulestoreBuilder(object):
     """
     A builder class for a MixedModuleStore.

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

@@ -846,3 +846,52 @@ class XMLModuleStore(ModuleStoreReadBase):
         if branch_setting != ModuleStoreEnum.Branch.published_only:
             raise ValueError(u"Cannot set branch setting to {} on a ReadOnly store".format(branch_setting))
         yield
+
+    def _find_course_asset(self, course_key, filename, get_thumbnail=False):
+        """
+        For now this is not implemented, but others should feel free to implement using the asset.json
+        which export produces.
+        """
+        raise NotImplementedError()
+
+    def _find_asset_info(self, asset_key, thumbnail=False, **kwargs):
+        """
+        For now this is not implemented, but others should feel free to implement using the asset.json
+        which export produces.
+        """
+        raise NotImplementedError()
+
+    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()
+
+    def find_asset_thumbnail_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()
+
+    def _get_all_asset_metadata(self, course_key, start=0, maxresults=-1, sort=None, get_thumbnails=False, **kwargs):
+        """
+        For now this is not implemented, but others should feel free to implement using the asset.json
+        which export produces.
+        """
+        raise NotImplementedError()
+
+    def get_all_asset_metadata(self, course_key, 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()
+
+    def get_all_asset_thumbnail_metadata(self, course_key, **kwargs):
+        """
+        For now this is not implemented, but others should feel free to implement using the asset.json
+        which export produces.
+        """
+        raise NotImplementedError()