From 37fc450b8b380d3b15f2d9ca0abfa3cda9da4f29 Mon Sep 17 00:00:00 2001
From: "J. Cliff Dyer" <cdyer@edx.org>
Date: Thu, 22 Sep 2016 11:07:35 -0400
Subject: [PATCH] Add version to VisibleBlocks model.

TNL-5600
---
 lms/djangoapps/grades/models.py            | 16 ++++++++++------
 lms/djangoapps/grades/tests/test_models.py | 13 ++++++++-----
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/lms/djangoapps/grades/models.py b/lms/djangoapps/grades/models.py
index dfb415e412..eabf9037ed 100644
--- a/lms/djangoapps/grades/models.py
+++ b/lms/djangoapps/grades/models.py
@@ -23,6 +23,8 @@ from xmodule_django.models import CourseKeyField, UsageKeyField
 log = logging.getLogger(__name__)
 
 
+BLOCK_RECORD_LIST_VERSION = 1
+
 # Used to serialize information about a block at the time it was used in
 # grade calculation.
 BlockRecord = namedtuple('BlockRecord', ['locator', 'weight', 'max_score'])
@@ -33,12 +35,13 @@ class BlockRecordList(tuple):
     An immutable ordered list of BlockRecord objects.
     """
 
-    def __new__(cls, blocks, course_key):  # pylint: disable=unused-argument
+    def __new__(cls, blocks, course_key, version=None):  # pylint: disable=unused-argument
         return super(BlockRecordList, cls).__new__(cls, blocks)
 
-    def __init__(self, blocks, course_key):
+    def __init__(self, blocks, course_key, version=None):
         super(BlockRecordList, self).__init__(blocks)
         self.course_key = course_key
+        self.version = version or BLOCK_RECORD_LIST_VERSION
 
     def __eq__(self, other):
         assert isinstance(other, BlockRecordList)
@@ -73,8 +76,9 @@ class BlockRecordList(tuple):
         for block_dict in list_of_block_dicts:
             block_dict['locator'] = unicode(block_dict['locator'])  # BlockUsageLocator is not json-serializable
         data = {
-            'course_key': unicode(self.course_key),
-            'blocks': list_of_block_dicts,
+            u'blocks': list_of_block_dicts,
+            u'course_key': unicode(self.course_key),
+            u'version': self.version,
         }
         return json.dumps(
             data,
@@ -98,7 +102,7 @@ class BlockRecordList(tuple):
             )
             for block in block_dicts
         )
-        return cls(record_generator, course_key)
+        return cls(record_generator, course_key, version=data['version'])
 
     @classmethod
     def from_list(cls, blocks, course_key):
@@ -121,7 +125,7 @@ class VisibleBlocksQuerySet(models.QuerySet):
         """
         model, _ = self.get_or_create(
             hashed=blocks.hash_value,
-            defaults={'blocks_json': blocks.json_value, 'course_id': blocks.course_key},
+            defaults={u'blocks_json': blocks.json_value, u'course_id': blocks.course_key},
         )
         return model
 
diff --git a/lms/djangoapps/grades/tests/test_models.py b/lms/djangoapps/grades/tests/test_models.py
index b4dc2dc77e..e3dd0a24a7 100644
--- a/lms/djangoapps/grades/tests/test_models.py
+++ b/lms/djangoapps/grades/tests/test_models.py
@@ -14,6 +14,7 @@ from opaque_keys.edx.locator import CourseLocator, BlockUsageLocator
 from lms.djangoapps.grades.models import (
     BlockRecord,
     BlockRecordList,
+    BLOCK_RECORD_LIST_VERSION,
     PersistentSubsectionGrade,
     VisibleBlocks
 )
@@ -32,7 +33,10 @@ class BlockRecordListTestCase(TestCase):
         )
 
     def test_empty_block_record_set(self):
-        empty_json = '{0}"blocks":[],"course_key":"{1}"{2}'.format('{', unicode(self.course_key), '}')
+        empty_json = u'{"blocks":[],"course_key":"%s","version":%s}' % (
+            unicode(self.course_key),
+            BLOCK_RECORD_LIST_VERSION,
+        )
 
         brs = BlockRecordList((), self.course_key)
         self.assertFalse(brs)
@@ -100,7 +104,7 @@ class BlockRecordTest(GradesModelTestCase):
     @ddt.unpack
     def test_serialization(self, weight, max_score, block_key):
         """
-        Tests serialization of a BlockRecord using the to_dict() method.
+        Tests serialization of a BlockRecord using the _asdict() method.
         """
         record = BlockRecord(block_key, weight, max_score)
         expected = OrderedDict([
@@ -130,10 +134,9 @@ class VisibleBlocksTest(GradesModelTestCase):
         for block_dict in list_of_block_dicts:
             block_dict['locator'] = unicode(block_dict['locator'])  # BlockUsageLocator is not json-serializable
         expected_data = {
+            'blocks': [{'locator': unicode(self.record_a.locator), 'max_score': 10, 'weight': 1}],
             'course_key': unicode(self.record_a.locator.course_key),
-            'blocks': [
-                {'locator': unicode(self.record_a.locator), 'max_score': 10, 'weight': 1},
-            ],
+            'version': BLOCK_RECORD_LIST_VERSION,
         }
         expected_json = json.dumps(expected_data, separators=(',', ':'), sort_keys=True)
         expected_hash = b64encode(sha1(expected_json).digest())