Fixed the preferences scope of xblock.

Added self to authors.

Conflicts:
	AUTHORS
	CHANGELOG.rst

AUTHORS

@@ -77,3 +77,4 @@ Slater Victoroff <slater.r.victoroff@gmail.com>
 Peter Fogg <peter.p.fogg@gmail.com>
 Bethany LaPenta <lapentab@mit.edu>
 Renzo Lucioni <renzolucioni@gmail.com>
+Felix Sun <felixsun@mit.edu>

CHANGELOG.rst

@@ -27,6 +27,8 @@ students' number of attempts to zero.  Provides a list of background
 tasks that are currently running for the course, and an option to
 see a history of background tasks for a given problem.
 
+LMS: Fixed the preferences scope for storing data in xmodules.
+
 LMS: Forums.  Added handling for case where discussion module can get `None` as
 value of lms.start in `lms/djangoapps/django_comment_client/utils.py`
 

lms/djangoapps/courseware/model_data.py

@@ -163,7 +163,7 @@ class ModelDataCache(object):
             return self._chunked_query(
                 XModuleStudentPrefsField,
                 'module_type__in',
-                set(descriptor.location.category for descriptor in self.descriptors),
+                set(descriptor.module_class.__name__ for descriptor in self.descriptors),
                 student=self.user.pk,
                 field_name__in=set(field.name for field in fields),
             )

lms/djangoapps/courseware/tests/factories.py

@@ -75,7 +75,7 @@ class StudentPrefsFactory(DjangoModelFactory):
     field_name = 'existing_field'
     value = json.dumps('old_value')
     student = SubFactory(UserFactory)
-    module_type = 'problem'
+    module_type = 'MockProblemModule'
 
 
 class StudentInfoFactory(DjangoModelFactory):

lms/djangoapps/courseware/tests/test_model_data.py

@@ -29,6 +29,7 @@ def mock_descriptor(fields=[], lms_fields=[]):
     descriptor.location = location('def_id')
     descriptor.module_class.fields = fields
     descriptor.module_class.lms.fields = lms_fields
+    descriptor.module_class.__name__ = 'MockProblemModule'
     return descriptor
 
 location = partial(Location, 'i4x', 'edX', 'test_course', 'problem')
@@ -37,7 +38,7 @@ course_id = 'edX/test_course/test'
 content_key = partial(LmsKeyValueStore.Key, Scope.content, None, location('def_id'))
 settings_key = partial(LmsKeyValueStore.Key, Scope.settings, None, location('def_id'))
 user_state_key = partial(LmsKeyValueStore.Key, Scope.user_state, 'user', location('def_id'))
-prefs_key = partial(LmsKeyValueStore.Key, Scope.preferences, 'user', 'problem')
+prefs_key = partial(LmsKeyValueStore.Key, Scope.preferences, 'user', 'MockProblemModule')
 user_info_key = partial(LmsKeyValueStore.Key, Scope.user_info, 'user', None)
 
 
@@ -190,6 +191,10 @@ class StorageTestBase(object):
         self.mdc = ModelDataCache([mock_descriptor([mock_field(self.scope, 'existing_field')])], course_id, self.user)
         self.kvs = LmsKeyValueStore(self.desc_md, self.mdc)
 
+    def test_set_and_get_existing_field(self):
+        self.kvs.set(self.key_factory('existing_field'), 'test_value')
+        self.assertEquals('test_value', self.kvs.get(self.key_factory('existing_field')))
+
     def test_get_existing_field(self):
         "Test that getting an existing field in an existing Storage Field works"
         self.assertEquals('old_value', self.kvs.get(self.key_factory('existing_field')))