TNL-5005 Persistent Grades Data Model

Introduces database models and simple CRUD interface for robust grading
usage.

lms/djangoapps/grades/course_grades.py

@@ -14,7 +14,7 @@ from .new.course_grade import CourseGradeFactory
 log = getLogger(__name__)
 
 
-GradeResult = namedtuple('StudentGrade', ['student', 'gradeset', 'err_msg'])
+GradeResult = namedtuple('GradeResult', ['student', 'gradeset', 'err_msg'])
 
 
 def iterate_grades_for(course_or_id, students):

lms/djangoapps/grades/migrations/0001_initial.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import coursewarehistoryextended.fields
+import django.utils.timezone
+import model_utils.fields
+import xmodule_django.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PersistentSubsectionGrade',
+            fields=[
+                ('created', model_utils.fields.AutoCreatedField(default=django.utils.timezone.now, verbose_name='created', editable=False)),
+                ('modified', model_utils.fields.AutoLastModifiedField(default=django.utils.timezone.now, verbose_name='modified', editable=False)),
+                ('id', coursewarehistoryextended.fields.UnsignedBigIntAutoField(serialize=False, primary_key=True)),
+                ('user_id', models.IntegerField()),
+                ('course_id', xmodule_django.models.CourseKeyField(max_length=255)),
+                ('usage_key', xmodule_django.models.UsageKeyField(max_length=255)),
+                ('subtree_edited_date', models.DateTimeField(verbose_name=b'last content edit timestamp')),
+                ('course_version', models.CharField(max_length=255, verbose_name=b'guid of latest course version', blank=True)),
+                ('earned_all', models.FloatField()),
+                ('possible_all', models.FloatField()),
+                ('earned_graded', models.FloatField()),
+                ('possible_graded', models.FloatField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='VisibleBlocks',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('blocks_json', models.TextField()),
+                ('hashed', models.CharField(unique=True, max_length=100)),
+            ],
+        ),
+        migrations.AddField(
+            model_name='persistentsubsectiongrade',
+            name='visible_blocks',
+            field=models.ForeignKey(to='grades.VisibleBlocks', db_column=b'visible_blocks_hash', to_field=b'hashed'),
+        ),
+        migrations.AlterUniqueTogether(
+            name='persistentsubsectiongrade',
+            unique_together=set([('course_id', 'user_id', 'usage_key')]),
+        ),
+    ]

lms/djangoapps/grades/tests/test_models.py

+"""
+Unit tests for grades models.
+"""
+from base64 import b64encode
+from collections import OrderedDict
+import ddt
+from hashlib import sha1
+import json
+from mock import patch
+
+from django.core.exceptions import ValidationError
+from django.test import TestCase
+from opaque_keys.edx.locator import CourseLocator, BlockUsageLocator
+
+from lms.djangoapps.grades.models import BlockRecord, BlockRecordSet, PersistentSubsectionGrade, VisibleBlocks
+
+
+class GradesModelTestCase(TestCase):
+    """
+    Base class for common setup of grades model tests.
+    """
+    def setUp(self):
+        super(GradesModelTestCase, self).setUp()
+        self.course_key = CourseLocator(
+            org='some_org',
+            course='some_course',
+            run='some_run'
+        )
+        self.locator_a = BlockUsageLocator(
+            course_key=self.course_key,
+            block_type='problem',
+            block_id='block_id_a'
+        )
+        self.locator_b = BlockUsageLocator(
+            course_key=self.course_key,
+            block_type='problem',
+            block_id='block_id_b'
+        )
+        self.record_a = BlockRecord(unicode(self.locator_a), 1, 10)
+        self.record_b = BlockRecord(unicode(self.locator_b), 1, 10)
+
+
+@ddt.ddt
+class BlockRecordTest(GradesModelTestCase):
+    """
+    Test the BlockRecord model.
+    """
+    def setUp(self):
+        super(BlockRecordTest, self).setUp()
+
+    def test_creation(self):
+        """
+        Tests creation of a BlockRecord.
+        """
+        weight = 1
+        max_score = 10
+        record = BlockRecord(
+            self.locator_a,
+            weight,
+            max_score,
+        )
+        self.assertEqual(record.locator, self.locator_a)
+
+    @ddt.data(
+        (0, 0, "0123456789abcdef"),
+        (1, 10, 'totally_a_real_block_key'),
+        ("BlockRecord is", "a dumb data store", "with no validation"),
+    )
+    @ddt.unpack
+    def test_serialization(self, weight, max_score, block_key):
+        """
+        Tests serialization of a BlockRecord using the to_dict() method.
+        """
+        record = BlockRecord(block_key, weight, max_score)
+        expected = OrderedDict([
+            ("locator", block_key),
+            ("weight", weight),
+            ("max_score", max_score),
+        ])
+        self.assertEqual(expected, record._asdict())
+
+
+class VisibleBlocksTest(GradesModelTestCase):
+    """
+    Test the VisibleBlocks model.
+    """
+    def test_creation(self):
+        """
+        Happy path test to ensure basic create functionality works as expected.
+        """
+        vblocks = VisibleBlocks.objects.create_from_blockrecords([self.record_a])
+        expected_json = json.dumps([self.record_a._asdict()], separators=(',', ':'), sort_keys=True)
+        expected_hash = b64encode(sha1(expected_json).digest())
+        self.assertEqual(expected_json, vblocks.blocks_json)
+        self.assertEqual(expected_hash, vblocks.hashed)
+
+    def test_ordering_does_not_matter(self):
+        """
+        When creating new vblocks, a different ordering of blocks produces the
+        same record in the database.
+        """
+        stored_vblocks = VisibleBlocks.objects.create_from_blockrecords([self.record_a, self.record_b])
+        repeat_vblocks = VisibleBlocks.objects.create_from_blockrecords([self.record_b, self.record_a])
+        new_vblocks = VisibleBlocks.objects.create_from_blockrecords([self.record_b])
+
+        self.assertEqual(stored_vblocks.pk, repeat_vblocks.pk)
+        self.assertEqual(stored_vblocks.hashed, repeat_vblocks.hashed)
+
+        self.assertNotEqual(stored_vblocks.pk, new_vblocks.pk)
+        self.assertNotEqual(stored_vblocks.hashed, new_vblocks.hashed)
+
+    def test_blocks_property(self):
+        """
+        Ensures that, given an array of BlockRecord, creating visible_blocks and accessing visible_blocks.blocks yields
+        a copy of the initial array. Also, trying to set the blocks property should raise an exception.
+        """
+        expected_blocks = [self.record_a, self.record_b]
+        visible_blocks = VisibleBlocks.objects.create_from_blockrecords(expected_blocks)
+        self.assertEqual(BlockRecordSet(expected_blocks), visible_blocks.blocks)
+        with self.assertRaises(AttributeError):
+            visible_blocks.blocks = expected_blocks
+
+
+@ddt.ddt
+class PersistentSubsectionGradeTest(GradesModelTestCase):
+    """
+    Test the PersistentSubsectionGrade model.
+    """
+    def setUp(self):
+        super(PersistentSubsectionGradeTest, self).setUp()
+        self.usage_key = BlockUsageLocator(
+            course_key=self.course_key,
+            block_type='subsection',
+            block_id='subsection_12345',
+        )
+        self.params = {
+            "user_id": 12345,
+            "usage_key": self.usage_key,
+            "course_version": "deadbeef",
+            "subtree_edited_date": "2016-08-01 18:53:24.354741",
+            "earned_all": 6,
+            "possible_all": 12,
+            "earned_graded": 6,
+            "possible_graded": 8,
+            "visible_blocks": [self.record_a, self.record_b],
+        }
+
+    def test_create(self):
+        """
+        Tests model creation, and confirms error when trying to recreate model.
+        """
+        created_grade = PersistentSubsectionGrade.objects.create(**self.params)
+        read_grade = PersistentSubsectionGrade.read_grade(
+            user_id=self.params["user_id"],
+            usage_key=self.params["usage_key"],
+        )
+        self.assertEqual(created_grade, read_grade)
+        with self.assertRaises(ValidationError):
+            created_grade = PersistentSubsectionGrade.objects.create(**self.params)
+
+    def test_create_bad_params(self):
+        """
+        Confirms create will fail if params are missing.
+        """
+        del self.params["earned_graded"]
+        with self.assertRaises(ValidationError):
+            PersistentSubsectionGrade.objects.create(**self.params)
+
+    def test_course_version_is_optional(self):
+        del self.params["course_version"]
+        PersistentSubsectionGrade.objects.create(**self.params)
+
+    def test_update_grade(self):
+        """
+        Tests model update, and confirms error when updating a nonexistent model.
+        """
+        with self.assertRaises(PersistentSubsectionGrade.DoesNotExist):
+            PersistentSubsectionGrade.update_grade(**self.params)
+        PersistentSubsectionGrade.objects.create(**self.params)
+        self.params['earned_all'] = 12
+        self.params['earned_graded'] = 8
+        PersistentSubsectionGrade.update_grade(**self.params)
+        read_grade = PersistentSubsectionGrade.read_grade(
+            user_id=self.params["user_id"],
+            usage_key=self.params["usage_key"],
+        )
+        self.assertEqual(read_grade.earned_all, 12)
+        self.assertEqual(read_grade.earned_graded, 8)
+
+    @ddt.data(True, False)
+    def test_save(self, already_created):
+        if already_created:
+            PersistentSubsectionGrade.objects.create(**self.params)
+        module_prefix = "lms.djangoapps.grades.models.PersistentSubsectionGrade."
+        with patch(
+            module_prefix + "objects.get_or_create",
+            wraps=PersistentSubsectionGrade.objects.get_or_create
+        ) as mock_get_or_create:
+            with patch(module_prefix + "update") as mock_update:
+                PersistentSubsectionGrade.save_grade(**self.params)
+                self.assertTrue(mock_get_or_create.called)
+                self.assertEqual(mock_update.called, already_created)

lms/envs/common.py

@@ -1891,7 +1891,7 @@ INSTALLED_APPS = (
     'openedx.core.djangoapps.course_groups',
     'bulk_email',
     'branding',
-    'grades',
+    'lms.djangoapps.grades',
 
     # Student support tools
     'support',