This adds a new django app -- edx-when -- that will copy start and due dates to mysql and allow per-learner overrides in the instructor dashboard, using the existing IDDE interface.

It adds a data migration for existing IDDE data.
2019-03-18 10:29:49 -04:00
parent 1dca07a237
commit b4ccd03740
30 changed files with 326 additions and 363 deletions
--- a/common/lib/xmodule/xmodule/modulestore/django.py
+++ b/common/lib/xmodule/xmodule/modulestore/django.py
@@ -198,6 +198,10 @@ class SignalHandler(object):
            log.info('Sent %s signal to %s with kwargs %s. Response was: %s', signal_name, receiver, kwargs, response)


+# to allow easy imports
+globals().update({sig.name.upper(): sig for sig in SignalHandler.all_signals()})
+
+
 def load_function(path):
    """
    Load a function by name.
--- a/lms/djangoapps/ccx/tests/test_field_override_performance.py
+++ b/lms/djangoapps/ccx/tests/test_field_override_performance.py
@@ -239,7 +239,7 @@ class TestFieldOverrideMongoPerformance(FieldOverridePerformanceTestCase):
    __test__ = True

    # TODO: decrease query count as part of REVO-28
-    QUERY_COUNT = 30
+    QUERY_COUNT = 32
    TEST_DATA = {
        # (providers, course_width, enable_ccx, view_as_ccx): (
        #     # of sql queries to default,
@@ -268,7 +268,8 @@ class TestFieldOverrideSplitPerformance(FieldOverridePerformanceTestCase):
    __test__ = True

    # TODO: decrease query count as part of REVO-28
-    QUERY_COUNT = 30
+    QUERY_COUNT = 32
+
    TEST_DATA = {
        ('no_overrides', 1, True, False): (QUERY_COUNT, 3),
        ('no_overrides', 2, True, False): (QUERY_COUNT, 3),
--- a/lms/djangoapps/course_api/blocks/tests/test_api.py
+++ b/lms/djangoapps/course_api/blocks/tests/test_api.py
@@ -7,9 +7,6 @@ from mock import patch

 import ddt
 from django.test.client import RequestFactory
-from django.test.utils import override_settings
-
-import course_blocks.api as course_blocks_api

 from openedx.core.djangoapps.content.block_structure.api import clear_course_from_cache
 from openedx.core.djangoapps.content.block_structure.config import STORAGE_BACKING_FOR_CACHE, waffle
@@ -209,7 +206,7 @@ class TestGetBlocksQueryCounts(TestGetBlocksQueryCountsBase):
            self._get_blocks(
                course,
                expected_mongo_queries=0,
-                expected_sql_queries=10 if with_storage_backing else 9,
+                expected_sql_queries=12 if with_storage_backing else 11,
            )

    @ddt.data(
@@ -226,57 +223,9 @@ class TestGetBlocksQueryCounts(TestGetBlocksQueryCountsBase):
            clear_course_from_cache(course.id)

            if with_storage_backing:
-                num_sql_queries = 20
+                num_sql_queries = 22
            else:
-                num_sql_queries = 10
-
-            self._get_blocks(
-                course,
-                expected_mongo_queries,
-                expected_sql_queries=num_sql_queries,
-            )
-
-
-@ddt.ddt
-@override_settings(FIELD_OVERRIDE_PROVIDERS=(course_blocks_api.INDIVIDUAL_STUDENT_OVERRIDE_PROVIDER, ))
-class TestQueryCountsWithIndividualOverrideProvider(TestGetBlocksQueryCountsBase):
-    """
-    Tests query counts for the get_blocks function when IndividualStudentOverrideProvider is set.
-    """
-
-    @ddt.data(
-        *product(
-            (ModuleStoreEnum.Type.mongo, ModuleStoreEnum.Type.split),
-            (True, False),
-        )
-    )
-    @ddt.unpack
-    def test_query_counts_cached(self, store_type, with_storage_backing):
-        with waffle().override(STORAGE_BACKING_FOR_CACHE, active=with_storage_backing):
-            course = self._create_course(store_type)
-            self._get_blocks(
-                course,
-                expected_mongo_queries=0,
-                expected_sql_queries=11 if with_storage_backing else 10,
-            )
-
-    @ddt.data(
-        *product(
-            ((ModuleStoreEnum.Type.mongo, 5), (ModuleStoreEnum.Type.split, 3)),
-            (True, False),
-        )
-    )
-    @ddt.unpack
-    def test_query_counts_uncached(self, store_type_tuple, with_storage_backing):
-        store_type, expected_mongo_queries = store_type_tuple
-        with waffle().override(STORAGE_BACKING_FOR_CACHE, active=with_storage_backing):
-            course = self._create_course(store_type)
-            clear_course_from_cache(course.id)
-
-            if with_storage_backing:
-                num_sql_queries = 21
-            else:
-                num_sql_queries = 11
+                num_sql_queries = 12

            self._get_blocks(
                course,
--- a/lms/djangoapps/course_blocks/api.py
+++ b/lms/djangoapps/course_blocks/api.py
@@ -4,17 +4,12 @@ get_course_blocks function.
 """
 from django.conf import settings

+from edx_when import field_data
 from openedx.core.djangoapps.content.block_structure.api import get_block_structure_manager
 from openedx.core.djangoapps.content.block_structure.transformers import BlockStructureTransformers
 from openedx.features.content_type_gating.block_transformers import ContentTypeGateTransformer

-from .transformers import (
-    library_content,
-    start_date,
-    user_partitions,
-    visibility,
-    load_override_data,
-)
+from .transformers import library_content, load_override_data, start_date, user_partitions, visibility
 from .usage_info import CourseUsageInfo

 INDIVIDUAL_STUDENT_OVERRIDE_PROVIDER = (
@@ -46,6 +41,7 @@ def get_course_block_access_transformers(user):
        ContentTypeGateTransformer(),
        user_partitions.UserPartitionTransformer(),
        visibility.VisibilityTransformer(),
+        field_data.DateOverrideTransformer(user),
    ]

    if has_individual_student_override_provider():
--- a/lms/djangoapps/course_blocks/transformers/access_denied_filter.py
+++ b/lms/djangoapps/course_blocks/transformers/access_denied_filter.py
@@ -2,9 +2,7 @@
 Access Denied Message Filter Transformer implementation.
 """
 # TODO: Remove this file after REVE-52 lands and old-mobile-app traffic falls to < 5% of mobile traffic
-from openedx.core.djangoapps.content.block_structure.transformer import (
-    BlockStructureTransformer
-)
+from openedx.core.djangoapps.content.block_structure.transformer import BlockStructureTransformer


 class AccessDeniedMessageFilterTransformer(BlockStructureTransformer):
--- a/lms/djangoapps/course_blocks/transformers/hide_empty.py
+++ b/lms/djangoapps/course_blocks/transformers/hide_empty.py
@@ -2,9 +2,7 @@
 Hide Empty Transformer implementation.
 """
 # TODO: Remove this file after REVE-52 lands and old-mobile-app traffic falls to < 5% of mobile traffic
-from openedx.core.djangoapps.content.block_structure.transformer import (
-    BlockStructureTransformer
-)
+from openedx.core.djangoapps.content.block_structure.transformer import BlockStructureTransformer


 class HideEmptyTransformer(BlockStructureTransformer):
--- a/lms/djangoapps/course_blocks/transformers/library_content.py
+++ b/lms/djangoapps/course_blocks/transformers/library_content.py
@@ -3,8 +3,9 @@ Content Library Transformer.
 """
 import json

-from courseware.models import StudentModule
 from eventtracking import tracker
+
+from courseware.models import StudentModule
 from openedx.core.djangoapps.content.block_structure.transformer import (
    BlockStructureTransformer,
    FilteringTransformerMixin
@@ -98,7 +99,7 @@ class ContentLibraryTransformer(FilteringTransformerMixin, BlockStructureTransfo
                # Save back any changes
                if any(block_keys[changed] for changed in ('invalid', 'overlimit', 'added')):
                    state_dict['selected'] = list(selected)
-                    StudentModule.save_state(  # pylint: disable=no-value-for-parameter
+                    StudentModule.save_state(
                        student=usage_info.user,
                        course_id=usage_info.course_key,
                        module_state_key=block_key,
--- a/lms/djangoapps/course_blocks/transformers/load_override_data.py
+++ b/lms/djangoapps/course_blocks/transformers/load_override_data.py
@@ -3,9 +3,8 @@ Load Override Data Transformer
 """
 import json

-from openedx.core.djangoapps.content.block_structure.transformer import BlockStructureTransformer
-
 from courseware.models import StudentFieldOverride
+from openedx.core.djangoapps.content.block_structure.transformer import BlockStructureTransformer

 # The list of fields are in support of Individual due dates and could be expanded for other use cases.
 REQUESTED_FIELDS = [
--- a/lms/djangoapps/courseware/migrations/0008_move_idde_to_edx_when.py
+++ b/lms/djangoapps/courseware/migrations/0008_move_idde_to_edx_when.py
@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.20 on 2019-03-21 15:25
+from __future__ import unicode_literals
+
+import json
+import logging
+from django.db import migrations
+
+
+def move_overrides_to_edx_when(apps, schema_editor):
+    from xmodule.fields import Date
+    from edx_when import api
+    date_field = Date()
+    StudentFieldOverride = apps.get_model('courseware', 'StudentFieldOverride')
+    log = logging.getLogger(__name__)
+    for override in StudentFieldOverride.objects.filter(field='due'):
+        try:
+            abs_date = date_field.from_json(json.loads(override.value))
+            api.set_date_for_block(
+                override.course_id,
+                override.location,
+                'due',
+                abs_date,
+                user=override.student)
+        except Exception:  # pylint: disable=broad-except
+            log.exception("migrating %d %r: %r", override.id, override.location, override.value)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('courseware', '0007_remove_done_index'),
+    ]
+
+    operations = [
+        migrations.RunPython(move_overrides_to_edx_when)
+    ]
--- a/lms/djangoapps/courseware/module_render.py
+++ b/lms/djangoapps/courseware/module_render.py
@@ -96,6 +96,8 @@ from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.exceptions import ItemNotFoundError
 from xmodule.x_module import XModuleDescriptor

+from edx_when.field_data import DateLookupFieldData
+

 log = logging.getLogger(__name__)

@@ -164,7 +166,6 @@ def toc_for_course(user, request, course, active_chapter, active_section, field_

    field_data_cache must include data from the course module and 2 levels of its descendants
    '''
-
    with modulestore().bulk_operations(course.id):
        course_module = get_module_for_descriptor(
            user, request, course, field_data_cache, course.id, course=course
@@ -660,6 +661,7 @@ def get_module_system_for_user(
            inner_system,
            real_user.id,
            [
+                partial(DateLookupFieldData, course_id=course_id, user=user),
                partial(OverrideFieldData.wrap, real_user, course),
                partial(LmsFieldData, student_data=inner_student_data),
            ],
@@ -755,7 +757,8 @@ def get_module_system_for_user(
    else:
        anonymous_student_id = anonymous_id_for_user(user, None)

-    field_data = LmsFieldData(descriptor._field_data, student_data)  # pylint: disable=protected-access
+    field_data = DateLookupFieldData(descriptor._field_data, course_id, user)  # pylint: disable=protected-access
+    field_data = LmsFieldData(field_data, student_data)

    user_is_staff = bool(has_access(user, u'staff', descriptor.location, course_id))

--- a/lms/djangoapps/courseware/tests/test_views.py
+++ b/lms/djangoapps/courseware/tests/test_views.py
@@ -213,8 +213,8 @@ class IndexQueryTestCase(ModuleStoreTestCase):
    NUM_PROBLEMS = 20

    @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 10, 176),
-        (ModuleStoreEnum.Type.split, 4, 170),
+        (ModuleStoreEnum.Type.mongo, 10, 178),
+        (ModuleStoreEnum.Type.split, 4, 172),
    )
    @ddt.unpack
    def test_index_query_counts(self, store_type, expected_mongo_query_count, expected_mysql_query_count):
@@ -1465,8 +1465,8 @@ class ProgressPageTests(ProgressPageBaseTests):
                self.assertContains(resp, u"Download Your Certificate")

    @ddt.data(
-        (True, 50),
-        (False, 49)
+        (True, 52),
+        (False, 51)
    )
    @ddt.unpack
    def test_progress_queries_paced_courses(self, self_paced, query_count):
@@ -1479,8 +1479,8 @@ class ProgressPageTests(ProgressPageBaseTests):

    @patch.dict(settings.FEATURES, {'ASSUME_ZERO_GRADE_IF_ABSENT_FOR_ALL_TESTS': False})
    @ddt.data(
-        (False, 58, 38),
-        (True, 49, 33)
+        (False, 60, 40),
+        (True, 51, 35)
    )
    @ddt.unpack
    def test_progress_queries(self, enable_waffle, initial, subsequent):
--- a/lms/djangoapps/grades/tests/test_tasks.py
+++ b/lms/djangoapps/grades/tests/test_tasks.py
@@ -175,10 +175,10 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
            self.assertEquals(mock_block_structure_create.call_count, 1)

    @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 36, True),
-        (ModuleStoreEnum.Type.mongo, 1, 36, False),
-        (ModuleStoreEnum.Type.split, 3, 36, True),
-        (ModuleStoreEnum.Type.split, 3, 36, False),
+        (ModuleStoreEnum.Type.mongo, 1, 38, True),
+        (ModuleStoreEnum.Type.mongo, 1, 38, False),
+        (ModuleStoreEnum.Type.split, 3, 38, True),
+        (ModuleStoreEnum.Type.split, 3, 38, False),
    )
    @ddt.unpack
    def test_query_counts(self, default_store, num_mongo_calls, num_sql_calls, create_multiple_subsections):
@@ -190,8 +190,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
                    self._apply_recalculate_subsection_grade()

    @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 36),
-        (ModuleStoreEnum.Type.split, 3, 36),
+        (ModuleStoreEnum.Type.mongo, 1, 38),
+        (ModuleStoreEnum.Type.split, 3, 38),
    )
    @ddt.unpack
    def test_query_counts_dont_change_with_more_content(self, default_store, num_mongo_calls, num_sql_calls):
@@ -236,8 +236,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
        )

    @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 19),
-        (ModuleStoreEnum.Type.split, 3, 19),
+        (ModuleStoreEnum.Type.mongo, 1, 21),
+        (ModuleStoreEnum.Type.split, 3, 21),
    )
    @ddt.unpack
    def test_persistent_grades_not_enabled_on_course(self, default_store, num_mongo_queries, num_sql_queries):
@@ -251,8 +251,8 @@ class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTest
            self.assertEqual(len(PersistentSubsectionGrade.bulk_read_grades(self.user.id, self.course.id)), 0)

    @ddt.data(
-        (ModuleStoreEnum.Type.mongo, 1, 37),
-        (ModuleStoreEnum.Type.split, 3, 37),
+        (ModuleStoreEnum.Type.mongo, 1, 39),
+        (ModuleStoreEnum.Type.split, 3, 39),
    )
    @ddt.unpack
    def test_persistent_grades_enabled_on_course(self, default_store, num_mongo_queries, num_sql_queries):
--- a/lms/djangoapps/instructor/tests/test_api.py
+++ b/lms/djangoapps/instructor/tests/test_api.py
@@ -3,6 +3,7 @@
 Unit tests for instructor.api methods.
 """
 from __future__ import print_function
+
 import datetime
 import functools
 import io
@@ -18,25 +19,21 @@ from django.conf import settings
 from django.contrib.auth.models import User
 from django.core import mail
 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.urls import reverse as django_reverse
 from django.http import HttpRequest, HttpResponse
 from django.test import RequestFactory, TestCase
 from django.test.utils import override_settings
-from pytz import UTC
+from django.urls import reverse as django_reverse
 from django.utils.translation import ugettext as _
 from mock import Mock, NonCallableMock, patch
 from opaque_keys.edx.keys import CourseKey
 from opaque_keys.edx.locator import UsageKey
+from pytz import UTC
 from six import text_type

-import lms.djangoapps.instructor.views.api
-import lms.djangoapps.instructor_task.api
 from bulk_email.models import BulkEmailFlag, CourseEmail, CourseEmailTemplate
-from lms.djangoapps.certificates.models import CertificateStatuses
-from lms.djangoapps.certificates.tests.factories import GeneratedCertificateFactory
 from course_modes.models import CourseMode
 from course_modes.tests.factories import CourseModeFactory
-from courseware.models import StudentFieldOverride, StudentModule
+from courseware.models import StudentModule
 from courseware.tests.factories import (
    BetaTesterFactory,
    GlobalStaffFactory,
@@ -47,6 +44,8 @@ from courseware.tests.factories import (
 from courseware.tests.helpers import LoginEnrollmentTestCase
 from django_comment_common.models import FORUM_ROLE_COMMUNITY_TA
 from django_comment_common.utils import seed_permissions_roles
+from lms.djangoapps.certificates.models import CertificateStatuses
+from lms.djangoapps.certificates.tests.factories import GeneratedCertificateFactory
 from lms.djangoapps.instructor.tests.utils import FakeContentTask, FakeEmail, FakeEmailInfo
 from lms.djangoapps.instructor.views.api import (
    _split_input_list,
@@ -63,6 +62,9 @@ from openedx.core.djangoapps.course_groups.cohorts import set_course_cohorted
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 from openedx.core.djangoapps.site_configuration.tests.mixins import SiteMixin
 from openedx.core.lib.xblock_utils import grade_histogram
+from edx_when.api import get_overrides_for_user
+from edx_when.signals import extract_dates
+
 from shoppingcart.models import (
    Coupon,
    CouponRedemption,
@@ -351,7 +353,7 @@ class TestEndpointHttpMethods(SharedModuleStoreTestCase, LoginEnrollmentTestCase
        """
        Tests that POST endpoints are rejected with 405 when using GET.
        """
-        url = reverse(data, kwargs={'course_id': unicode(self.course.id)})
+        url = reverse(data, kwargs={'course_id': text_type(self.course.id)})
        response = self.client.get(url)

        self.assertEqual(
@@ -366,7 +368,7 @@ class TestEndpointHttpMethods(SharedModuleStoreTestCase, LoginEnrollmentTestCase
        """
        Tests that GET endpoints are not rejected with 405 when using GET.
        """
-        url = reverse(data, kwargs={'course_id': unicode(self.course.id)})
+        url = reverse(data, kwargs={'course_id': text_type(self.course.id)})
        response = self.client.get(url)

        self.assertNotEqual(
@@ -630,10 +632,10 @@ class TestInstructorAPIBulkAccountCreationAndEnrollment(SharedModuleStoreTestCas
        CourseModeFactory.create(course_id=cls.audit_course.id, mode_slug=CourseMode.AUDIT)

        cls.url = reverse(
-            'register_and_enroll_students', kwargs={'course_id': unicode(cls.course.id)}
+            'register_and_enroll_students', kwargs={'course_id': text_type(cls.course.id)}
        )
        cls.audit_course_url = reverse(
-            'register_and_enroll_students', kwargs={'course_id': unicode(cls.audit_course.id)}
+            'register_and_enroll_students', kwargs={'course_id': text_type(cls.audit_course.id)}
        )

    def setUp(self):
@@ -649,7 +651,7 @@ class TestInstructorAPIBulkAccountCreationAndEnrollment(SharedModuleStoreTestCas
        )

        self.white_label_course_url = reverse(
-            'register_and_enroll_students', kwargs={'course_id': unicode(self.white_label_course.id)}
+            'register_and_enroll_students', kwargs={'course_id': text_type(self.white_label_course.id)}
        )

        self.request = RequestFactory().request()
@@ -969,8 +971,8 @@ class TestInstructorAPIBulkAccountCreationAndEnrollment(SharedModuleStoreTestCas
        manual_enrollments = ManualEnrollmentAudit.objects.all()
        self.assertEqual(manual_enrollments.count(), 2)

-    @patch.object(lms.djangoapps.instructor.views.api, 'generate_random_string',
-                  Mock(side_effect=['first', 'first', 'second']))
+    @patch('lms.djangoapps.instructor.views.api', 'generate_random_string',
+           Mock(side_effect=['first', 'first', 'second']))
    def test_generate_unique_password_no_reuse(self):
        """
        generate_unique_password should generate a unique password string that hasn't been generated before.
@@ -2899,7 +2901,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        """
        url = reverse(
            'get_problem_responses',
-            kwargs={'course_id': unicode(self.course.id)}
+            kwargs={'course_id': text_type(self.course.id)}
        )
        problem_location = ''

@@ -2934,7 +2936,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        """
        url = reverse(
            'get_problem_responses',
-            kwargs={'course_id': unicode(self.course.id)}
+            kwargs={'course_id': text_type(self.course.id)}
        )
        problem_location = ''

@@ -2954,7 +2956,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        """
        url = reverse(
            'get_problem_responses',
-            kwargs={'course_id': unicode(self.course.id)}
+            kwargs={'course_id': text_type(self.course.id)}
        )
        task_type = 'problem_responses_csv'
        already_running_status = generate_already_running_error_message(task_type)
@@ -3030,7 +3032,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        """
        url = reverse(
            'get_students_who_may_enroll',
-            kwargs={'course_id': unicode(self.course.id)}
+            kwargs={'course_id': text_type(self.course.id)}
        )
        # Successful case:
        response = self.client.post(url, {})
@@ -3052,7 +3054,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        """
        url = reverse(
            'get_proctored_exam_results',
-            kwargs={'course_id': unicode(self.course.id)}
+            kwargs={'course_id': text_type(self.course.id)}
        )

        # Successful case:
@@ -3254,8 +3256,8 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
        response = self.client.post(url, {})
        self.assertIn('The detailed enrollment report is being created.', response.content)

-    @patch.object(lms.djangoapps.instructor.views.api, 'anonymous_id_for_user', Mock(return_value='42'))
-    @patch.object(lms.djangoapps.instructor.views.api, 'unique_id_for_user', Mock(return_value='41'))
+    @patch('lms.djangoapps.instructor.views.api.anonymous_id_for_user', Mock(return_value='42'))
+    @patch('lms.djangoapps.instructor.views.api.unique_id_for_user', Mock(return_value='41'))
    def test_get_anon_ids(self):
        """
        Test the CSV output for the anonymized user ids.
@@ -3323,7 +3325,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
    @ddt.unpack
    @valid_problem_location
    def test_calculate_report_csv_success(self, report_type, instructor_api_endpoint, task_api_endpoint, extra_instructor_api_kwargs):
-        kwargs = {'course_id': unicode(self.course.id)}
+        kwargs = {'course_id': text_type(self.course.id)}
        kwargs.update(extra_instructor_api_kwargs)
        url = reverse(instructor_api_endpoint, kwargs=kwargs)
        success_status = u"The {report_type} report is being created.".format(report_type=report_type)
@@ -3348,7 +3350,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
            task_api_endpoint,
            extra_instructor_api_kwargs
    ):  # pylint: disable=unused-argument
-        kwargs = {'course_id': unicode(self.course.id)}
+        kwargs = {'course_id': text_type(self.course.id)}
        kwargs.update(extra_instructor_api_kwargs)
        url = reverse(instructor_api_endpoint, kwargs=kwargs)

@@ -3370,7 +3372,7 @@ class TestInstructorAPILevelsDataDump(SharedModuleStoreTestCase, LoginEnrollment
            task_api_endpoint,
            extra_instructor_api_kwargs
    ):
-        kwargs = {'course_id': unicode(self.course.id)}
+        kwargs = {'course_id': text_type(self.course.id)}
        kwargs.update(extra_instructor_api_kwargs)
        url = reverse(instructor_api_endpoint, kwargs=kwargs)

@@ -3494,7 +3496,7 @@ class TestInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginEnrollmentTes
        )

    # mock out the function which should be called to execute the action.
-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_reset_problem_attempts_for_all_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_reset_problem_attempts_for_all_students')
    def test_reset_student_attempts_all(self, act):
        """ Test reset all student attempts. """
        url = reverse('reset_student_attempts', kwargs={'course_id': text_type(self.course.id)})
@@ -3544,7 +3546,7 @@ class TestInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginEnrollmentTes
        })
        self.assertEqual(response.status_code, 400)

-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_rescore_problem_for_student')
+    @patch('lms.djangoapps.instructor_task.api.submit_rescore_problem_for_student')
    def test_rescore_problem_single(self, act):
        """ Test rescoring of a single student. """
        url = reverse('rescore_problem', kwargs={'course_id': text_type(self.course.id)})
@@ -3555,7 +3557,7 @@ class TestInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginEnrollmentTes
        self.assertEqual(response.status_code, 200)
        self.assertTrue(act.called)

-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_rescore_problem_for_student')
+    @patch('lms.djangoapps.instructor_task.api.submit_rescore_problem_for_student')
    def test_rescore_problem_single_from_uname(self, act):
        """ Test rescoring of a single student. """
        url = reverse('rescore_problem', kwargs={'course_id': text_type(self.course.id)})
@@ -3566,7 +3568,7 @@ class TestInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginEnrollmentTes
        self.assertEqual(response.status_code, 200)
        self.assertTrue(act.called)

-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_rescore_problem_for_all_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_rescore_problem_for_all_students')
    def test_rescore_problem_all(self, act):
        """ Test rescoring for all students. """
        url = reverse('rescore_problem', kwargs={'course_id': text_type(self.course.id)})
@@ -3694,7 +3696,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_reset_entrance_exam_student_attempts_delete_all(self):
        """ Make sure no one can delete all students state on entrance exam. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'all_students': True,
            'delete_module': True,
@@ -3704,7 +3706,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_reset_entrance_exam_student_attempts_single(self):
        """ Test reset single student attempts for entrance exam. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3718,11 +3720,11 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
            )

    # mock out the function which should be called to execute the action.
-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_reset_problem_attempts_in_entrance_exam')
+    @patch('lms.djangoapps.instructor_task.api.submit_reset_problem_attempts_in_entrance_exam')
    def test_reset_entrance_exam_all_student_attempts(self, act):
        """ Test reset all student attempts for entrance exam. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'all_students': True,
        })
@@ -3732,7 +3734,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_reset_student_attempts_invalid_entrance_exam(self):
        """ Test reset for invalid entrance exam. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course_with_invalid_ee.id)})
+                      kwargs={'course_id': text_type(self.course_with_invalid_ee.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3741,7 +3743,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_entrance_exam_student_delete_state(self):
        """ Test delete single student entrance exam state. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
            'delete_module': True,
@@ -3757,7 +3759,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
        staff_user = StaffFactory(course_key=self.course.id)
        self.client.login(username=staff_user.username, password='test')
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
            'delete_module': True,
@@ -3767,17 +3769,17 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_entrance_exam_reset_student_attempts_nonsense(self):
        """ Test failure with both unique_student_identifier and all_students. """
        url = reverse('reset_student_attempts_for_entrance_exam',
-                      kwargs={'course_id': unicode(self.course.id)})
+                      kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
            'all_students': True,
        })
        self.assertEqual(response.status_code, 400)

-    @patch.object(lms.djangoapps.instructor_task.api, 'submit_rescore_entrance_exam_for_student')
+    @patch('lms.djangoapps.instructor_task.api.submit_rescore_entrance_exam_for_student')
    def test_rescore_entrance_exam_single_student(self, act):
        """ Test re-scoring of entrance exam for single student. """
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3786,7 +3788,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE

    def test_rescore_entrance_exam_all_student(self):
        """ Test rescoring for all students. """
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'all_students': True,
        })
@@ -3794,7 +3796,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE

    def test_rescore_entrance_exam_if_higher_all_student(self):
        """ Test rescoring for all students only if higher. """
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'all_students': True,
            'only_if_higher': True,
@@ -3803,7 +3805,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE

    def test_rescore_entrance_exam_all_student_and_single(self):
        """ Test re-scoring with both all students and single student parameters. """
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
            'all_students': True,
@@ -3812,7 +3814,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE

    def test_rescore_entrance_exam_with_invalid_exam(self):
        """ Test re-scoring of entrance exam with invalid exam. """
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course_with_invalid_ee.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course_with_invalid_ee.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3821,13 +3823,13 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_list_entrance_exam_instructor_tasks_student(self):
        """ Test list task history for entrance exam AND student. """
        # create a re-score entrance exam task
-        url = reverse('rescore_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('rescore_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
        self.assertEqual(response.status_code, 200)

-        url = reverse('list_entrance_exam_instructor_tasks', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('list_entrance_exam_instructor_tasks', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3840,7 +3842,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE

    def test_list_entrance_exam_instructor_tasks_all_student(self):
        """ Test list task history for entrance exam AND all student. """
-        url = reverse('list_entrance_exam_instructor_tasks', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('list_entrance_exam_instructor_tasks', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {})
        self.assertEqual(response.status_code, 200)

@@ -3851,7 +3853,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_list_entrance_exam_instructor_with_invalid_exam_key(self):
        """ Test list task history for entrance exam failure if course has invalid exam. """
        url = reverse('list_entrance_exam_instructor_tasks',
-                      kwargs={'course_id': unicode(self.course_with_invalid_ee.id)})
+                      kwargs={'course_id': text_type(self.course_with_invalid_ee.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -3860,7 +3862,7 @@ class TestEntranceExamInstructorAPIRegradeTask(SharedModuleStoreTestCase, LoginE
    def test_skip_entrance_exam_student(self):
        """ Test skip entrance exam api for student. """
        # create a re-score entrance exam task
-        url = reverse('mark_student_can_skip_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('mark_student_can_skip_entrance_exam', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.student.email,
        })
@@ -4095,7 +4097,7 @@ class TestInstructorAPITaskLists(SharedModuleStoreTestCase, LoginEnrollmentTestC
        self.tasks = [self.FakeTask(mock_factory.mock_get_task_completion_info) for _ in xrange(7)]
        self.tasks[-1].make_invalid_output()

-    @patch.object(lms.djangoapps.instructor_task.api, 'get_running_instructor_tasks')
+    @patch('lms.djangoapps.instructor_task.api.get_running_instructor_tasks')
    def test_list_instructor_tasks_running(self, act):
        """ Test list of all running tasks. """
        act.return_value = self.tasks
@@ -4116,7 +4118,7 @@ class TestInstructorAPITaskLists(SharedModuleStoreTestCase, LoginEnrollmentTestC
            self.assertDictEqual(exp_task, act_task)
        self.assertEqual(actual_tasks, expected_tasks)

-    @patch.object(lms.djangoapps.instructor_task.api, 'get_instructor_task_history')
+    @patch('lms.djangoapps.instructor_task.api.get_instructor_task_history')
    def test_list_background_email_tasks(self, act):
        """Test list of background email tasks."""
        act.return_value = self.tasks
@@ -4137,7 +4139,7 @@ class TestInstructorAPITaskLists(SharedModuleStoreTestCase, LoginEnrollmentTestC
            self.assertDictEqual(exp_task, act_task)
        self.assertEqual(actual_tasks, expected_tasks)

-    @patch.object(lms.djangoapps.instructor_task.api, 'get_instructor_task_history')
+    @patch('lms.djangoapps.instructor_task.api.get_instructor_task_history')
    def test_list_instructor_tasks_problem(self, act):
        """ Test list task history for problem. """
        act.return_value = self.tasks
@@ -4160,7 +4162,7 @@ class TestInstructorAPITaskLists(SharedModuleStoreTestCase, LoginEnrollmentTestC
            self.assertDictEqual(exp_task, act_task)
        self.assertEqual(actual_tasks, expected_tasks)

-    @patch.object(lms.djangoapps.instructor_task.api, 'get_instructor_task_history')
+    @patch('lms.djangoapps.instructor_task.api.get_instructor_task_history')
    def test_list_instructor_tasks_problem_student(self, act):
        """ Test list task history for problem AND student. """
        act.return_value = self.tasks
@@ -4186,7 +4188,7 @@ class TestInstructorAPITaskLists(SharedModuleStoreTestCase, LoginEnrollmentTestC
        self.assertEqual(actual_tasks, expected_tasks)


-@patch.object(lms.djangoapps.instructor_task.api, 'get_instructor_task_history', autospec=True)
+@patch('lms.djangoapps.instructor_task.api.get_instructor_task_history', autospec=True)
 class TestInstructorEmailContentList(SharedModuleStoreTestCase, LoginEnrollmentTestCase):
    """
    Test the instructor email content history endpoint.
@@ -4347,7 +4349,7 @@ class TestInstructorAPIHelpers(TestCase):
        course_id = CourseKey.from_string('MITx/6.002x/2013_Spring')
        name = 'L2Node1'
        output = 'i4x://MITx/6.002x/problem/L2Node1'
-        self.assertEqual(unicode(msk_from_problem_urlname(course_id, name)), output)
+        self.assertEqual(text_type(msk_from_problem_urlname(course_id, name)), output)

    def test_msk_from_problem_urlname_error(self):
        args = ('notagoodcourse', 'L2Node1')
@@ -4360,16 +4362,14 @@ def get_extended_due(course, unit, user):
    Gets the overridden due date for the given user on the given unit.  Returns
    `None` if there is no override set.
    """
-    try:
-        override = StudentFieldOverride.objects.get(
-            course_id=course.id,
-            student=user,
-            location=unit.location,
-            field='due'
-        )
-        return DATE_FIELD.from_json(json.loads(override.value))
-    except StudentFieldOverride.DoesNotExist:
-        return None
+    location = text_type(unit.location)
+    dates = get_overrides_for_user(course.id, user)
+    for override in dates:
+        if text_type(override['location']) == location:
+            return override['actual_date']
+    print(unit.location)
+    print(dates)
+    return None


 class TestDueDateExtensions(SharedModuleStoreTestCase, LoginEnrollmentTestCase):
@@ -4453,6 +4453,7 @@ class TestDueDateExtensions(SharedModuleStoreTestCase, LoginEnrollmentTestCase):
        self.user2 = user2
        self.instructor = InstructorFactory(course_key=self.course.id)
        self.client.login(username=self.instructor.username, password='test')
+        extract_dates(None, self.course.id)

    def test_change_due_date(self):
        url = reverse('change_due_date', kwargs={'course_id': text_type(self.course.id)})
@@ -4500,18 +4501,10 @@ class TestDueDateExtensions(SharedModuleStoreTestCase, LoginEnrollmentTestCase):
        })
        self.assertEqual(response.status_code, 200, response.content)
        self.assertEqual(
-            None,
+            self.due,
            get_extended_due(self.course, self.week1, self.user1)
        )

-    def test_reset_nonexistent_extension(self):
-        url = reverse('reset_due_date', kwargs={'course_id': text_type(self.course.id)})
-        response = self.client.post(url, {
-            'student': self.user1.username,
-            'url': text_type(self.week1.location),
-        })
-        self.assertEqual(response.status_code, 400, response.content)
-
    def test_show_unit_extensions(self):
        self.test_change_due_date()
        url = reverse('show_unit_extensions',
@@ -4619,6 +4612,7 @@ class TestDueDateExtensionsDeletedDate(ModuleStoreTestCase, LoginEnrollmentTestC
        self.user2 = user2
        self.instructor = InstructorFactory(course_key=self.course.id)
        self.client.login(username=self.instructor.username, password='test')
+        extract_dates(None, self.course.id)

    def test_reset_extension_to_deleted_date(self):
        """
@@ -4638,6 +4632,7 @@ class TestDueDateExtensionsDeletedDate(ModuleStoreTestCase, LoginEnrollmentTestC

        self.week1.due = None
        self.week1 = self.store.update_item(self.week1, self.user1.id)
+        extract_dates(None, self.course.id)
        # Now, week1's normal due date is deleted but the extension still exists.
        url = reverse('reset_due_date', kwargs={'course_id': text_type(self.course.id)})
        response = self.client.post(url, {
@@ -4646,7 +4641,7 @@ class TestDueDateExtensionsDeletedDate(ModuleStoreTestCase, LoginEnrollmentTestC
        })
        self.assertEqual(response.status_code, 200, response.content)
        self.assertEqual(
-            None,
+            self.due,
            get_extended_due(self.course, self.week1, self.user1)
        )

@@ -4681,7 +4676,7 @@ class TestCourseIssuedCertificatesData(SharedModuleStoreTestCase):
        """
        Test certificates with status 'downloadable' should be in the response.
        """
-        url = reverse('get_issued_certificates', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('get_issued_certificates', kwargs={'course_id': text_type(self.course.id)})
        # firstly generating downloadable certificates with 'honor' mode
        certificate_count = 3
        for __ in xrange(certificate_count):
@@ -4703,7 +4698,7 @@ class TestCourseIssuedCertificatesData(SharedModuleStoreTestCase):
        """
        Test for certificate csv features against mode. Certificates should be group by 'mode' in reponse.
        """
-        url = reverse('get_issued_certificates', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('get_issued_certificates', kwargs={'course_id': text_type(self.course.id)})
        # firstly generating downloadable certificates with 'honor' mode
        certificate_count = 3
        for __ in xrange(certificate_count):
@@ -4744,7 +4739,7 @@ class TestCourseIssuedCertificatesData(SharedModuleStoreTestCase):
        """
        Test for certificate csv features.
        """
-        url = reverse('get_issued_certificates', kwargs={'course_id': unicode(self.course.id)})
+        url = reverse('get_issued_certificates', kwargs={'course_id': text_type(self.course.id)})
        # firstly generating downloadable certificates with 'honor' mode
        certificate_count = 3
        for __ in xrange(certificate_count):
@@ -4929,8 +4924,8 @@ class TestCourseRegistrationCodes(SharedModuleStoreTestCase):
                                and row_data[1].endswith('/shoppingcart/register/redeem/{0}/"'.format(code)))
            index += 1

-    @patch.object(lms.djangoapps.instructor.views.api, 'random_code_generator',
-                  Mock(side_effect=['first', 'second', 'third', 'fourth']))
+    @patch('lms.djangoapps.instructor.views.api.random_code_generator',
+           Mock(side_effect=['first', 'second', 'third', 'fourth']))
    def test_generate_course_registration_codes_matching_existing_coupon_code(self):
        """
        Test the generated course registration code is already in the Coupon Table
@@ -4955,8 +4950,8 @@ class TestCourseRegistrationCodes(SharedModuleStoreTestCase):
        self.assertTrue(body.startswith(EXPECTED_CSV_HEADER))
        self.assertEqual(len(body.split('\n')), 5)  # 1 for headers, 1 for new line at the end and 3 for the actual data

-    @patch.object(lms.djangoapps.instructor.views.api, 'random_code_generator',
-                  Mock(side_effect=['first', 'first', 'second', 'third']))
+    @patch('lms.djangoapps.instructor.views.api.random_code_generator',
+           Mock(side_effect=['first', 'first', 'second', 'third']))
    def test_generate_course_registration_codes_integrity_error(self):
        """
       Test for the Integrity error against the generated code
@@ -5248,7 +5243,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
        with open(file_name, 'w') as file_pointer:
            file_pointer.write(csv_data.encode('utf-8'))
        with open(file_name, 'r') as file_pointer:
-            url = reverse('add_users_to_cohorts', kwargs={'course_id': unicode(self.course.id)})
+            url = reverse('add_users_to_cohorts', kwargs={'course_id': text_type(self.course.id)})
            return self.client.post(url, {'uploaded-file': file_pointer})

    def expect_error_on_file_content(self, file_content, error, file_suffix='.csv'):
@@ -5318,7 +5313,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
        response = self.call_add_users_to_cohorts('')
        self.assertEqual(response.status_code, 403)

-    @patch('lms.djangoapps.instructor.views.api.lms.djangoapps.instructor_task.api.submit_cohort_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_cohort_students')
    @patch('lms.djangoapps.instructor.views.api.store_uploaded_file')
    def test_success_username(self, mock_store_upload, mock_cohort_task):
        """
@@ -5329,7 +5324,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
            'username,cohort\nfoo_username,bar_cohort', mock_store_upload, mock_cohort_task
        )

-    @patch('lms.djangoapps.instructor.views.api.lms.djangoapps.instructor_task.api.submit_cohort_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_cohort_students')
    @patch('lms.djangoapps.instructor.views.api.store_uploaded_file')
    def test_success_email(self, mock_store_upload, mock_cohort_task):
        """
@@ -5340,7 +5335,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
            'email,cohort\nfoo_email,bar_cohort', mock_store_upload, mock_cohort_task
        )

-    @patch('lms.djangoapps.instructor.views.api.lms.djangoapps.instructor_task.api.submit_cohort_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_cohort_students')
    @patch('lms.djangoapps.instructor.views.api.store_uploaded_file')
    def test_success_username_and_email(self, mock_store_upload, mock_cohort_task):
        """
@@ -5351,7 +5346,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
            'username,email,cohort\nfoo_username,bar_email,baz_cohort', mock_store_upload, mock_cohort_task
        )

-    @patch('lms.djangoapps.instructor.views.api.lms.djangoapps.instructor_task.api.submit_cohort_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_cohort_students')
    @patch('lms.djangoapps.instructor.views.api.store_uploaded_file')
    def test_success_carriage_return(self, mock_store_upload, mock_cohort_task):
        """
@@ -5362,7 +5357,7 @@ class TestBulkCohorting(SharedModuleStoreTestCase):
            'username,email,cohort\rfoo_username,bar_email,baz_cohort', mock_store_upload, mock_cohort_task
        )

-    @patch('lms.djangoapps.instructor.views.api.lms.djangoapps.instructor_task.api.submit_cohort_students')
+    @patch('lms.djangoapps.instructor_task.api.submit_cohort_students')
    @patch('lms.djangoapps.instructor.views.api.store_uploaded_file')
    def test_success_carriage_return_line_feed(self, mock_store_upload, mock_cohort_task):
        """
--- a/lms/djangoapps/instructor/tests/test_api_email_localization.py
+++ b/lms/djangoapps/instructor/tests/test_api_email_localization.py
@@ -4,8 +4,8 @@ Unit tests for the localization of emails sent by instructor.api methods.
 """

 from django.core import mail
-from django.urls import reverse
 from django.test.utils import override_settings
+from django.urls import reverse
 from six import text_type

 from courseware.tests.factories import InstructorFactory
--- a/lms/djangoapps/instructor/tests/test_certificates.py
+++ b/lms/djangoapps/instructor/tests/test_certificates.py
@@ -4,17 +4,19 @@ import io
 import json
 from datetime import datetime, timedelta

-import ddt
 import mock
 import pytz
-from config_models.models import cache
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist
 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.urls import reverse
 from django.test.utils import override_settings
+from django.urls import reverse

+import ddt
 from capa.xqueue_interface import XQueueInterface
+from config_models.models import cache
+from course_modes.models import CourseMode
+from courseware.tests.factories import GlobalStaffFactory, InstructorFactory, UserFactory
 from lms.djangoapps.certificates import api as certs_api
 from lms.djangoapps.certificates.models import (
    CertificateGenerationConfiguration,
@@ -28,8 +30,6 @@ from lms.djangoapps.certificates.tests.factories import (
    CertificateWhitelistFactory,
    GeneratedCertificateFactory
 )
-from course_modes.models import CourseMode
-from courseware.tests.factories import GlobalStaffFactory, InstructorFactory, UserFactory
 from lms.djangoapps.grades.tests.utils import mock_passing_grade
 from lms.djangoapps.verify_student.services import IDVerificationService
 from lms.djangoapps.verify_student.tests.factories import SoftwareSecurePhotoVerificationFactory
--- a/lms/djangoapps/instructor/tests/test_enrollment.py
+++ b/lms/djangoapps/instructor/tests/test_enrollment.py
@@ -8,15 +8,15 @@ import json
 from abc import ABCMeta

 import ddt
-import mock
 from ccx_keys.locator import CCXLocator
+from crum import set_current_request
 from django.conf import settings
-from django.utils.translation import override as override_language
 from django.utils.translation import get_language
+from django.utils.translation import override as override_language
 from mock import patch
 from opaque_keys.edx.locator import CourseLocator
 from six import text_type
-from crum import set_current_request
+from submissions import api as sub_api

 from capa.tests.response_xml_factory import MultipleChoiceResponseXMLFactory
 from courseware.models import StudentModule
@@ -38,7 +38,6 @@ from openedx.core.djangolib.testing.utils import CacheIsolationTestCase, get_moc
 from student.models import CourseEnrollment, CourseEnrollmentAllowed, anonymous_id_for_user
 from student.roles import CourseCcxCoachRole
 from student.tests.factories import AdminFactory, UserFactory
-from submissions import api as sub_api
 from xmodule.modulestore.tests.django_utils import TEST_DATA_SPLIT_MODULESTORE, SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory

@@ -372,7 +371,7 @@ class TestInstructorEnrollmentStudentModule(SharedModuleStoreTestCase):
        reset_student_attempts(self.course_key, self.user, msk, requesting_user=self.user)
        self.assertEqual(json.loads(module().state)['attempts'], 0)

-    @mock.patch('lms.djangoapps.grades.signals.handlers.PROBLEM_WEIGHTED_SCORE_CHANGED.send')
+    @patch('lms.djangoapps.grades.signals.handlers.PROBLEM_WEIGHTED_SCORE_CHANGED.send')
    def test_delete_student_attempts(self, _mock_signal):
        msk = self.course_key.make_usage_key('dummy', 'module')
        original_state = json.dumps({'attempts': 32, 'otherstuff': 'alsorobots'})
@@ -398,9 +397,9 @@ class TestInstructorEnrollmentStudentModule(SharedModuleStoreTestCase):

    # Disable the score change signal to prevent other components from being
    # pulled into tests.
-    @mock.patch('lms.djangoapps.grades.signals.handlers.PROBLEM_WEIGHTED_SCORE_CHANGED.send')
-    @mock.patch('lms.djangoapps.grades.signals.handlers.submissions_score_set_handler')
-    @mock.patch('lms.djangoapps.grades.signals.handlers.submissions_score_reset_handler')
+    @patch('lms.djangoapps.grades.signals.handlers.PROBLEM_WEIGHTED_SCORE_CHANGED.send')
+    @patch('lms.djangoapps.grades.signals.handlers.submissions_score_set_handler')
+    @patch('lms.djangoapps.grades.signals.handlers.submissions_score_reset_handler')
    def test_delete_submission_scores(self, _mock_send_signal, mock_set_receiver, mock_reset_receiver):
        user = UserFactory()
        problem_location = self.course_key.make_usage_key('dummy', 'module')
@@ -746,7 +745,7 @@ class TestGetEmailParams(SharedModuleStoreTestCase):
    def test_marketing_params(self):
        # For a site with a marketing front end, what do we expect to get for the URLs?
        # Also make sure `auto_enroll` is properly passed through.
-        with mock.patch.dict('django.conf.settings.FEATURES', {'ENABLE_MKTG_SITE': True}):
+        with patch.dict('django.conf.settings.FEATURES', {'ENABLE_MKTG_SITE': True}):
            result = get_email_params(self.course, True)

        self.assertEqual(result['auto_enroll'], True)
--- a/lms/djangoapps/instructor/tests/test_proctoring.py
+++ b/lms/djangoapps/instructor/tests/test_proctoring.py
@@ -2,18 +2,16 @@
 Unit tests for Edx Proctoring feature flag in new instructor dashboard.
 """

-import ddt
 from django.apps import apps
 from django.conf import settings
 from django.urls import reverse
-
-from edx_proctoring.api import create_exam
-from edx_proctoring.backends.tests.test_backend import TestBackendProvider
-
 from mock import patch
 from six import text_type

-from student.roles import CourseStaffRole, CourseInstructorRole
+import ddt
+from edx_proctoring.api import create_exam
+from edx_proctoring.backends.tests.test_backend import TestBackendProvider
+from student.roles import CourseInstructorRole, CourseStaffRole
 from student.tests.factories import AdminFactory
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
--- a/lms/djangoapps/instructor/tests/test_registration_codes.py
+++ b/lms/djangoapps/instructor/tests/test_registration_codes.py
@@ -3,8 +3,8 @@ Test for the registration code status information.
 """
 import json

-from django.urls import reverse
 from django.test.utils import override_settings
+from django.urls import reverse
 from django.utils.translation import ugettext as _
 from six import text_type

--- a/lms/djangoapps/instructor/tests/test_tools.py
+++ b/lms/djangoapps/instructor/tests/test_tools.py
@@ -1,6 +1,7 @@
 """
 Tests for views/tools.py.
 """
+from __future__ import absolute_import, unicode_literals

 import datetime
 import json
@@ -11,13 +12,11 @@ import six
 from django.contrib.auth.models import User
 from django.core.exceptions import MultipleObjectsReturned
 from django.test import TestCase
-from django.test.utils import override_settings
-from pytz import UTC
 from opaque_keys.edx.keys import CourseKey
-from six import text_type
+from pytz import UTC

-from lms.djangoapps.courseware.field_overrides import OverrideFieldData
-from lms.djangoapps.ccx.tests.test_overrides import inject_field_overrides
+from edx_when import signals
+from edx_when.field_data import DateLookupFieldData
 from student.tests.factories import UserFactory
 from xmodule.fields import Date
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase, SharedModuleStoreTestCase
@@ -118,7 +117,7 @@ class TestFindUnit(SharedModuleStoreTestCase):
        """
        Test finding a nested unit.
        """
-        url = text_type(self.homework.location)
+        url = six.text_type(self.homework.location)
        found_unit = tools.find_unit(self.course, url)
        self.assertEqual(found_unit.location, self.homework.location)

@@ -161,7 +160,7 @@ class TestGetUnitsWithDueDate(ModuleStoreTestCase):
            """
            URLs for sequence of nodes.
            """
-            return sorted(text_type(i.location) for i in seq)
+            return sorted(six.text_type(i.location) for i in seq)

        self.assertEquals(
            urls(tools.get_units_with_due_date(self.course)),
@@ -177,6 +176,7 @@ class TestTitleOrUrl(unittest.TestCase):
        self.assertEquals(tools.title_or_url(unit), 'hello')

    def test_url(self):
+        # pylint: disable=unused-argument
        def mock_location_text(self):
            """
            Mock implementation of __unicode__ or __str__ for the unit's location.
@@ -191,10 +191,13 @@ class TestTitleOrUrl(unittest.TestCase):
        self.assertEquals(tools.title_or_url(unit), u'test:hello')


-@override_settings(
-    FIELD_OVERRIDE_PROVIDERS=(
-        'lms.djangoapps.courseware.student_field_overrides.IndividualStudentOverrideProvider',),
-)
+def inject_field_data(blocks, course, user):
+    use_cached = False
+    for block in blocks:
+        block._field_data = DateLookupFieldData(block._field_data, course.id, user, use_cached=use_cached)   # pylint: disable=protected-access
+        use_cached = True
+
+
 class TestSetDueDateExtension(ModuleStoreTestCase):
    """
    Test the set_due_date_extensions function.
@@ -212,6 +215,7 @@ class TestSetDueDateExtension(ModuleStoreTestCase):
        week3 = ItemFactory.create(parent=course)
        homework = ItemFactory.create(parent=week1)
        assignment = ItemFactory.create(parent=homework, due=due)
+        signals.extract_dates(None, course.id)

        user = UserFactory.create()

@@ -223,11 +227,7 @@ class TestSetDueDateExtension(ModuleStoreTestCase):
        self.week3 = week3
        self.user = user

-        inject_field_overrides((course, week1, week2, week3, homework, assignment), course, user)
-
-    def tearDown(self):
-        super(TestSetDueDateExtension, self).tearDown()
-        OverrideFieldData.provider_classes = None
+        inject_field_data((course, week1, week2, week3, homework, assignment), course, user)

    def _clear_field_data_cache(self):
        """
@@ -237,22 +237,18 @@ class TestSetDueDateExtension(ModuleStoreTestCase):
        """
        for block in (self.week1, self.week2, self.week3,
                      self.homework, self.assignment):
+            block._field_data._load_dates(self.course.id, self.user, use_cached=False)  # pylint: disable=protected-access
            block.fields['due']._del_cached_value(block)  # pylint: disable=protected-access

    def test_set_due_date_extension(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.week1, self.user, extended)
+        tools.set_due_date_extension(self.course, self.assignment, self.user, extended)
        self._clear_field_data_cache()
        self.assertEqual(self.week1.due, extended)
        self.assertEqual(self.homework.due, extended)
        self.assertEqual(self.assignment.due, extended)

-    def test_set_due_date_extension_num_queries(self):
-        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
-        with self.assertNumQueries(5):
-            tools.set_due_date_extension(self.course, self.week1, self.user, extended)
-            self._clear_field_data_cache()
-
    def test_set_due_date_extension_invalid_date(self):
        extended = datetime.datetime(2009, 1, 1, 0, 0, tzinfo=UTC)
        with self.assertRaises(tools.DashboardError):
@@ -299,6 +295,7 @@ class TestDataDumps(ModuleStoreTestCase):
        self.week2 = week2
        self.user1 = user1
        self.user2 = user2
+        signals.extract_dates(None, course.id)

    def test_dump_module_extensions(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
@@ -307,12 +304,12 @@ class TestDataDumps(ModuleStoreTestCase):
        tools.set_due_date_extension(self.course, self.week1, self.user2,
                                     extended)
        report = tools.dump_module_extensions(self.course, self.week1)
-        self.assertEqual(
-            report['title'], u'Users with due date extensions for ' +
+        assert (
+            report['title'] == 'Users with due date extensions for ' +
            self.week1.display_name)
-        self.assertEqual(
-            report['header'], ["Username", "Full Name", "Extended Due Date"])
-        self.assertEqual(report['data'], [
+        assert (
+            report['header'] == ["Username", "Full Name", "Extended Due Date"])
+        assert (report['data'] == [
            {"Username": self.user1.username,
             "Full Name": self.user1.profile.name,
             "Extended Due Date": "2013-12-25 00:00"},
@@ -327,12 +324,12 @@ class TestDataDumps(ModuleStoreTestCase):
        tools.set_due_date_extension(self.course, self.week2, self.user1,
                                     extended)
        report = tools.dump_student_extensions(self.course, self.user1)
-        self.assertEqual(
-            report['title'], u'Due date extensions for %s (%s)' %
+        assert (
+            report['title'] == 'Due date extensions for %s (%s)' %
            (self.user1.profile.name, self.user1.username))
-        self.assertEqual(
-            report['header'], ["Unit", "Extended Due Date"])
-        self.assertEqual(report['data'], [
+        assert (
+            report['header'] == ["Unit", "Extended Due Date"])
+        assert (report['data'] == [
            {"Unit": self.week1.display_name,
             "Extended Due Date": "2013-12-25 00:00"},
            {"Unit": self.week2.display_name,
--- a/lms/djangoapps/instructor/views/api.py
+++ b/lms/djangoapps/instructor/views/api.py
@@ -18,18 +18,13 @@ import time
 import unicodecsv
 from django.conf import settings
 from django.contrib.auth.models import User
-from django.core.exceptions import (
-    MultipleObjectsReturned,
-    ObjectDoesNotExist,
-    PermissionDenied,
-    ValidationError
-)
+from django.core.exceptions import MultipleObjectsReturned, ObjectDoesNotExist, PermissionDenied, ValidationError
 from django.core.mail.message import EmailMessage
-from django.urls import reverse
 from django.core.validators import validate_email
 from django.db import IntegrityError, transaction
 from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseForbidden, HttpResponseNotFound
 from django.shortcuts import redirect
+from django.urls import reverse
 from django.utils.decorators import method_decorator
 from django.utils.html import strip_tags
 from django.utils.translation import ugettext as _
@@ -44,34 +39,37 @@ from rest_framework import permissions, status
 from rest_framework.response import Response
 from rest_framework.views import APIView
 from six import text_type
+from submissions import api as sub_api  # installed from the edx-submissions repository

 import instructor_analytics.basic
 import instructor_analytics.csvs
 import instructor_analytics.distributions
-import lms.djangoapps.instructor.enrollment as enrollment
-import lms.djangoapps.instructor_task.api
 from bulk_email.models import BulkEmailFlag, CourseEmail
-from lms.djangoapps.certificates import api as certs_api
-from lms.djangoapps.certificates.models import (
-    CertificateInvalidation, CertificateStatuses, CertificateWhitelist, GeneratedCertificate,
-)
 from courseware.access import has_access
 from courseware.courses import get_course_by_id, get_course_with_access
 from courseware.models import StudentModule
 from django_comment_client.utils import (
-    has_forum_access,
    get_course_discussion_settings,
+    get_group_id_for_user,
    get_group_name,
-    get_group_id_for_user
+    has_forum_access
 )
 from django_comment_common.models import (
-    Role,
    FORUM_ROLE_ADMINISTRATOR,
-    FORUM_ROLE_MODERATOR,
-    FORUM_ROLE_GROUP_MODERATOR,
    FORUM_ROLE_COMMUNITY_TA,
+    FORUM_ROLE_GROUP_MODERATOR,
+    FORUM_ROLE_MODERATOR,
+    Role
 )
 from edxmako.shortcuts import render_to_string
+from lms.djangoapps.certificates import api as certs_api
+from lms.djangoapps.certificates.models import (
+    CertificateInvalidation,
+    CertificateStatuses,
+    CertificateWhitelist,
+    GeneratedCertificate
+)
+from lms.djangoapps.instructor import enrollment
 from lms.djangoapps.instructor.access import ROLES, allow_access, list_with_level, revoke_access, update_forum_role
 from lms.djangoapps.instructor.enrollment import (
    enroll_email,
@@ -83,7 +81,7 @@ from lms.djangoapps.instructor.enrollment import (
 )
 from lms.djangoapps.instructor.views import INVOICE_KEY
 from lms.djangoapps.instructor.views.instructor_task_helpers import extract_email_features, extract_task_features
-from lms.djangoapps.instructor_task.api import submit_override_score
+from lms.djangoapps.instructor_task import api as task_api
 from lms.djangoapps.instructor_task.api_helper import AlreadyRunningError, QueueConnectionError
 from lms.djangoapps.instructor_task.models import ReportStore
 from openedx.core.djangoapps.content.course_overviews.models import CourseOverview
@@ -119,11 +117,10 @@ from student.models import (
    UserProfile,
    anonymous_id_for_user,
    get_user_by_username_or_email,
-    unique_id_for_user,
-    is_email_retired
+    is_email_retired,
+    unique_id_for_user
 )
 from student.roles import CourseFinanceAdminRole, CourseSalesAdminRole
-from submissions import api as sub_api  # installed from the edx-submissions repository
 from util.file import (
    FileValidationException,
    UniversalNewlineIterator,
@@ -210,7 +207,7 @@ def require_post_params(*args, **kwargs):
                    error_response_data['parameters'].append(param)
                    error_response_data['info'][param] = extra

-            if len(error_response_data['parameters']) > 0:
+            if error_response_data['parameters']:
                return JsonResponse(error_response_data, status=400)
            else:
                return func(*args, **kwargs)
@@ -319,11 +316,12 @@ def register_and_enroll_students(request, course_id):  # pylint: disable=too-man

    -If the email address already exists, but the username is different,
    match on the email address only and continue to enroll the user in the course using the email address
-    as the matching criteria. Note the change of username as a warning message (but not a failure). Send a standard enrollment email
-    which is the same as the existing manual enrollment
+    as the matching criteria. Note the change of username as a warning message (but not a failure).
+    Send a standard enrollment email which is the same as the existing manual enrollment

-    -If the username already exists (but not the email), assume it is a different user and fail to create the new account.
-     The failure will be messaged in a response in the browser.
+    -If the username already exists (but not the email), assume it is a different user and fail
+    to create the new account.
+    The failure will be messaged in a response in the browser.
    """

    if not configuration_helpers.get_value(
@@ -373,11 +371,13 @@ def register_and_enroll_students(request, course_id):  # pylint: disable=too-man

            # verify that we have exactly four columns in every row but allow for blank lines
            if len(student) != 4:
-                if len(student) > 0:
+                if student:
+                    error = _(u'Data in row #{row_num} must have exactly four columns: '
+                              'email, username, full name, and country').format(row_num=row_num)
                    general_errors.append({
                        'username': '',
                        'email': '',
-                        'response': _(u'Data in row #{row_num} must have exactly four columns: email, username, full name, and country').format(row_num=row_num)
+                        'response': error
                    })
                continue

@@ -392,7 +392,10 @@ def register_and_enroll_students(request, course_id):  # pylint: disable=too-man
                validate_email(email)  # Raises ValidationError if invalid
            except ValidationError:
                row_errors.append({
-                    'username': username, 'email': email, 'response': _('Invalid email {email_address}.').format(email_address=email)})
+                    'username': username,
+                    'email': email,
+                    'response': _(u'Invalid email {email_address}.').format(email_address=email)
+                })
            else:
                if User.objects.filter(email=email).exists():
                    # Email address already exists. assume it is the correct user
@@ -429,7 +432,11 @@ def register_and_enroll_students(request, course_id):  # pylint: disable=too-man
                            reason='Enrolling via csv upload',
                            state_transition=UNENROLLED_TO_ENROLLED,
                        )
-                        enroll_email(course_id=course_id, student_email=email, auto_enroll=True, email_students=True, email_params=email_params)
+                        enroll_email(course_id=course_id,
+                                     student_email=email,
+                                     auto_enroll=True,
+                                     email_students=True,
+                                     email_params=email_params)
                elif is_email_retired(email):
                    # We are either attempting to enroll a retired user or create a new user with an email which is
                    # already associated with a retired account.  Simply block these attempts.
@@ -573,7 +580,9 @@ def create_and_enroll_user(email, username, name, country, password, course_id,
            )
    except IntegrityError:
        errors.append({
-            'username': username, 'email': email, 'response': _(u'Username {user} already exists.').format(user=username)
+            'username': username,
+            'email': email,
+            'response': _(u'Username {user} already exists.').format(user=username)
        })
    except Exception as ex:  # pylint: disable=broad-except
        log.exception(type(ex).__name__)
@@ -1027,7 +1036,7 @@ def get_problem_responses(request, course_id):
    except InvalidKeyError:
        return JsonResponseBadRequest(_("Could not find problem with this location."))

-    task = lms.djangoapps.instructor_task.api.submit_calculate_problem_responses_csv(
+    task = task_api.submit_calculate_problem_responses_csv(
        request, course_key, problem_location
    )
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)
@@ -1317,7 +1326,7 @@ def get_students_features(request, course_id, csv=False):  # pylint: disable=red
        return JsonResponse(response_payload)

    else:
-        lms.djangoapps.instructor_task.api.submit_calculate_students_features_csv(
+        task_api.submit_calculate_students_features_csv(
            request,
            course_key,
            query_features
@@ -1345,7 +1354,7 @@ def get_students_who_may_enroll(request, course_id):
    course_key = CourseKey.from_string(course_id)
    query_features = ['email']
    report_type = _('enrollment')
-    lms.djangoapps.instructor_task.api.submit_calculate_may_enroll_csv(request, course_key, query_features)
+    task_api.submit_calculate_may_enroll_csv(request, course_key, query_features)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -1392,7 +1401,7 @@ def add_users_to_cohorts(request, course_id):
            validator=_cohorts_csv_validator
        )
        # The task will assume the default file storage.
-        lms.djangoapps.instructor_task.api.submit_cohort_students(request, course_key, filename)
+        task_api.submit_cohort_students(request, course_key, filename)
    except (FileValidationException, PermissionDenied) as err:
        return JsonResponse({"error": unicode(err)}, status=400)

@@ -1436,7 +1445,7 @@ class CohortCSV(DeveloperErrorViewMixin, APIView):
                max_file_size=2000000,  # limit to 2 MB
                validator=_cohorts_csv_validator
            )
-            lms.djangoapps.instructor_task.api.submit_cohort_students(request, course_key, file_name)
+            task_api.submit_cohort_students(request, course_key, file_name)
        except (FileValidationException, ValueError) as e:
            raise self.api_error(status.HTTP_400_BAD_REQUEST, str(e), 'failed-validation')
        return Response(status=status.HTTP_204_NO_CONTENT)
@@ -1484,7 +1493,7 @@ def get_enrollment_report(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('detailed enrollment')
-    lms.djangoapps.instructor_task.api.submit_detailed_enrollment_features_csv(request, course_key)
+    task_api.submit_detailed_enrollment_features_csv(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -1503,7 +1512,7 @@ def get_exec_summary_report(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('executive summary')
-    lms.djangoapps.instructor_task.api.submit_executive_summary_report(request, course_key)
+    task_api.submit_executive_summary_report(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -1521,7 +1530,7 @@ def get_course_survey_results(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('survey')
-    lms.djangoapps.instructor_task.api.submit_course_survey_report(request, course_key)
+    task_api.submit_course_survey_report(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -1539,7 +1548,7 @@ def get_proctored_exam_results(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('proctored exam results')
-    lms.djangoapps.instructor_task.api.submit_proctored_exam_results_report(request, course_key)
+    task_api.submit_proctored_exam_results_report(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -1916,7 +1925,8 @@ def get_anon_ids(request, course_id):  # pylint: disable=unused-argument
        courseenrollment__course_id=course_id,
    ).order_by('id')
    header = ['User ID', 'Anonymized User ID', 'Course Specific Anonymized User ID']
-    rows = [[s.id, unique_id_for_user(s, save=False), anonymous_id_for_user(s, course_id, save=False)] for s in students]
+    rows = [[s.id, unique_id_for_user(s, save=False), anonymous_id_for_user(s, course_id, save=False)]
+            for s in students]
    return csv_response(text_type(course_id).replace('/', '-') + '-anon-ids.csv', header, rows)


@@ -2085,7 +2095,7 @@ def reset_student_attempts(request, course_id):
            return HttpResponse(error_msg, status=500)
        response_payload['student'] = student_identifier
    elif all_students:
-        lms.djangoapps.instructor_task.api.submit_reset_problem_attempts_for_all_students(request, module_state_key)
+        task_api.submit_reset_problem_attempts_for_all_students(request, module_state_key)
        response_payload['task'] = TASK_SUBMISSION_OK
        response_payload['student'] = 'All Students'
    else:
@@ -2151,13 +2161,13 @@ def reset_student_attempts_for_entrance_exam(request, course_id):
    try:
        entrance_exam_key = UsageKey.from_string(course.entrance_exam_id).map_into_course(course_id)
        if delete_module:
-            lms.djangoapps.instructor_task.api.submit_delete_entrance_exam_state_for_student(
+            task_api.submit_delete_entrance_exam_state_for_student(
                request,
                entrance_exam_key,
                student
            )
        else:
-            lms.djangoapps.instructor_task.api.submit_reset_problem_attempts_in_entrance_exam(
+            task_api.submit_reset_problem_attempts_in_entrance_exam(
                request,
                entrance_exam_key,
                student
@@ -2220,7 +2230,7 @@ def rescore_problem(request, course_id):
    if student:
        response_payload['student'] = student_identifier
        try:
-            lms.djangoapps.instructor_task.api.submit_rescore_problem_for_student(
+            task_api.submit_rescore_problem_for_student(
                request,
                module_state_key,
                student,
@@ -2231,7 +2241,7 @@ def rescore_problem(request, course_id):

    elif all_students:
        try:
-            lms.djangoapps.instructor_task.api.submit_rescore_problem_for_all_students(
+            task_api.submit_rescore_problem_for_all_students(
                request,
                module_state_key,
                only_if_higher,
@@ -2286,7 +2296,7 @@ def override_problem_score(request, course_id):
        'student': student_identifier
    }
    try:
-        submit_override_score(
+        task_api.submit_override_score(
            request,
            usage_key,
            student,
@@ -2353,7 +2363,7 @@ def rescore_entrance_exam(request, course_id):
    else:
        response_payload['student'] = _("All Students")

-    lms.djangoapps.instructor_task.api.submit_rescore_entrance_exam_for_student(
+    task_api.submit_rescore_entrance_exam_for_student(
        request, entrance_exam_key, student, only_if_higher,
    )
    response_payload['task'] = TASK_SUBMISSION_OK
@@ -2371,7 +2381,7 @@ def list_background_email_tasks(request, course_id):  # pylint: disable=unused-a
    course_id = CourseKey.from_string(course_id)
    task_type = 'bulk_course_email'
    # Specifying for the history of a single task type
-    tasks = lms.djangoapps.instructor_task.api.get_instructor_task_history(
+    tasks = task_api.get_instructor_task_history(
        course_id,
        task_type=task_type
    )
@@ -2393,7 +2403,7 @@ def list_email_content(request, course_id):  # pylint: disable=unused-argument
    course_id = CourseKey.from_string(course_id)
    task_type = 'bulk_course_email'
    # First get tasks list of bulk emails sent
-    emails = lms.djangoapps.instructor_task.api.get_instructor_task_history(course_id, task_type=task_type)
+    emails = task_api.get_instructor_task_history(course_id, task_type=task_type)

    response_payload = {
        'emails': map(extract_email_features, emails),
@@ -2433,13 +2443,13 @@ def list_instructor_tasks(request, course_id):
            return HttpResponseBadRequest()
        if student:
            # Specifying for a single student's history on this problem
-            tasks = lms.djangoapps.instructor_task.api.get_instructor_task_history(course_id, module_state_key, student)
+            tasks = task_api.get_instructor_task_history(course_id, module_state_key, student)
        else:
            # Specifying for single problem's history
-            tasks = lms.djangoapps.instructor_task.api.get_instructor_task_history(course_id, module_state_key)
+            tasks = task_api.get_instructor_task_history(course_id, module_state_key)
    else:
        # If no problem or student, just get currently running tasks
-        tasks = lms.djangoapps.instructor_task.api.get_running_instructor_tasks(course_id)
+        tasks = task_api.get_running_instructor_tasks(course_id)

    response_payload = {
        'tasks': map(extract_task_features, tasks),
@@ -2471,14 +2481,14 @@ def list_entrance_exam_instructor_tasks(request, course_id):
        return HttpResponseBadRequest(_("Course has no valid entrance exam section."))
    if student:
        # Specifying for a single student's entrance exam history
-        tasks = lms.djangoapps.instructor_task.api.get_entrance_exam_instructor_task_history(
+        tasks = task_api.get_entrance_exam_instructor_task_history(
            course_id,
            entrance_exam_key,
            student
        )
    else:
        # Specifying for all student's entrance exam history
-        tasks = lms.djangoapps.instructor_task.api.get_entrance_exam_instructor_task_history(
+        tasks = task_api.get_entrance_exam_instructor_task_history(
            course_id,
            entrance_exam_key
        )
@@ -2546,7 +2556,7 @@ def export_ora2_data(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('ORA data')
-    lms.djangoapps.instructor_task.api.submit_export_ora2_data(request, course_key)
+    task_api.submit_export_ora2_data(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -2564,7 +2574,7 @@ def calculate_grades_csv(request, course_id):
    """
    report_type = _('grade')
    course_key = CourseKey.from_string(course_id)
-    lms.djangoapps.instructor_task.api.submit_calculate_grades_csv(request, course_key)
+    task_api.submit_calculate_grades_csv(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -2586,7 +2596,7 @@ def problem_grade_report(request, course_id):
    """
    course_key = CourseKey.from_string(course_id)
    report_type = _('problem grade')
-    lms.djangoapps.instructor_task.api.submit_problem_grade_report(request, course_key)
+    task_api.submit_problem_grade_report(request, course_key)
    success_status = SUCCESS_MESSAGE_TEMPLATE.format(report_type=report_type)

    return JsonResponse({"status": success_status})
@@ -2730,7 +2740,7 @@ def send_email(request, course_id):
        return HttpResponseBadRequest(repr(err))

    # Submit the task, so that the correct InstructorTask object gets created (for monitoring purposes)
-    lms.djangoapps.instructor_task.api.submit_bulk_course_email(request, course_id, email.id)
+    task_api.submit_bulk_course_email(request, course_id, email.id)

    response_payload = {
        'course_id': text_type(course_id),
@@ -2846,7 +2856,7 @@ def change_due_date(request, course_id):
    student = require_student_from_identifier(request.POST.get('student'))
    unit = find_unit(course, request.POST.get('url'))
    due_date = parse_datetime(request.POST.get('due_datetime'))
-    set_due_date_extension(course, unit, student, due_date)
+    set_due_date_extension(course, unit, student, due_date, request.user)

    return JsonResponse(_(
        u'Successfully changed due date for student {0} for {1} '
@@ -2867,7 +2877,7 @@ def reset_due_date(request, course_id):
    course = get_course_by_id(CourseKey.from_string(course_id))
    student = require_student_from_identifier(request.POST.get('student'))
    unit = find_unit(course, request.POST.get('url'))
-    set_due_date_extension(course, unit, student, None)
+    set_due_date_extension(course, unit, student, None, request.user)
    if not getattr(unit, "due", None):
        # It's possible the normal due date was deleted after an extension was granted:
        return JsonResponse(
@@ -3020,7 +3030,7 @@ def start_certificate_generation(request, course_id):
    Start generating certificates for all students enrolled in given course.
    """
    course_key = CourseKey.from_string(course_id)
-    task = lms.djangoapps.instructor_task.api.generate_certificates_for_students(request, course_key)
+    task = task_api.generate_certificates_for_students(request, course_key)
    message = _('Certificate generation task for all students of this course has been started. '
                'You can view the status of the generation task in the "Pending Tasks" section.')
    response_payload = {
@@ -3064,7 +3074,7 @@ def start_certificate_regeneration(request, course_id):
            status=400
        )

-    lms.djangoapps.instructor_task.api.regenerate_certificates(request, course_key, certificates_statuses)
+    task_api.regenerate_certificates(request, course_key, certificates_statuses)
    response_payload = {
        'message': _('Certificate regeneration task has been started. '
                     'You can view the status of the generation task in the "Pending Tasks" section.'),
@@ -3121,7 +3131,7 @@ def add_certificate_exception(course_key, student, certificate_exception):
    :param certificate_exception: A dict object containing certificate exception info.
    :return: CertificateWhitelist item in dict format containing certificate exception info.
    """
-    if len(CertificateWhitelist.get_certificate_white_list(course_key, student)) > 0:
+    if CertificateWhitelist.get_certificate_white_list(course_key, student):
        raise ValueError(
            _(u"Student (username/email={user}) already in certificate exception list.").format(user=student.username)
        )
@@ -3283,7 +3293,7 @@ def generate_certificate_exceptions(request, course_id, generate_for=None):
            status=400
        )

-    lms.djangoapps.instructor_task.api.generate_certificates_for_students(request, course_key, student_set=students)
+    task_api.generate_certificates_for_students(request, course_key, student_set=students)
    response_payload = {
        'success': True,
        'message': _('Certificate generation started for white listed students.'),
@@ -3343,7 +3353,7 @@ def generate_bulk_certificate_exceptions(request, course_id):
            # verify that we have exactly two column in every row either email or username and notes but allow for
            # blank lines
            if len(student) != 2:
-                if len(student) > 0:
+                if student:
                    build_row_errors('data_format_error', student[user_index], row_num)
                    log.info(u'invalid data/format in csv row# %s', row_num)
                continue
@@ -3355,7 +3365,7 @@ def generate_bulk_certificate_exceptions(request, course_id):
                build_row_errors('user_not_exist', user, row_num)
                log.info(u'student %s does not exist', user)
            else:
-                if len(CertificateWhitelist.get_certificate_white_list(course_key, user)) > 0:
+                if CertificateWhitelist.get_certificate_white_list(course_key, user):
                    build_row_errors('user_already_white_listed', user, row_num)
                    log.warning(u'student %s already exist.', user.username)

@@ -3433,10 +3443,10 @@ def invalidate_certificate(request, generated_certificate, certificate_invalidat
    :param certificate_invalidation_data: dict object containing data for CertificateInvalidation.
    :return: dict object containing updated certificate invalidation data.
    """
-    if len(CertificateInvalidation.get_certificate_invalidations(
+    if CertificateInvalidation.get_certificate_invalidations(
            generated_certificate.course_id,
            generated_certificate.user,
-    )) > 0:
+    ):
        raise ValueError(
            _(u"Certificate of {user} has already been invalidated. Please check your spelling and retry.").format(
                user=generated_certificate.user.username,
@@ -3493,7 +3503,7 @@ def re_validate_certificate(request, course_key, generated_certificate):
    # We need to generate certificate only for a single student here
    student = certificate_invalidation.generated_certificate.user

-    lms.djangoapps.instructor_task.api.generate_certificates_for_students(
+    task_api.generate_certificates_for_students(
        request, course_key, student_set="specific_student", specific_student_id=student.id
    )

@@ -3542,4 +3552,4 @@ def _create_error_response(request, msg):
    Creates the appropriate error response for the current request,
    in JSON form.
    """
-    return JsonResponse({"error": _(msg)}, 400)
+    return JsonResponse({"error": msg}, 400)
--- a/lms/djangoapps/instructor/views/gradebook_api.py
+++ b/lms/djangoapps/instructor/views/gradebook_api.py
@@ -5,8 +5,8 @@ which is currently use by ccx and instructor apps.
 import math

 from django.contrib.auth.models import User
-from django.urls import reverse
 from django.db import transaction
+from django.urls import reverse
 from django.views.decorators.cache import cache_control
 from opaque_keys.edx.keys import CourseKey

--- a/lms/djangoapps/instructor/views/instructor_dashboard.py
+++ b/lms/djangoapps/instructor/views/instructor_dashboard.py
@@ -10,8 +10,8 @@ from urlparse import urljoin
 import pytz
 from django.conf import settings
 from django.contrib.auth.decorators import login_required
-from django.urls import reverse
 from django.http import Http404, HttpResponseServerError
+from django.urls import reverse
 from django.utils.html import escape
 from django.utils.translation import ugettext as _
 from django.utils.translation import ugettext_noop
@@ -26,6 +26,13 @@ from xblock.field_data import DictFieldData
 from xblock.fields import ScopeIds

 from bulk_email.models import BulkEmailFlag
+from class_dashboard.dashboard_data import get_array_section_has_problem, get_section_display_name
+from course_modes.models import CourseMode, CourseModesArchive
+from courseware.access import has_access
+from courseware.courses import get_course_by_id, get_studio_url
+from django_comment_client.utils import available_division_schemes, has_forum_access
+from django_comment_common.models import FORUM_ROLE_ADMINISTRATOR, CourseDiscussionSettings
+from edxmako.shortcuts import render_to_response
 from lms.djangoapps.certificates import api as certs_api
 from lms.djangoapps.certificates.models import (
    CertificateGenerationConfiguration,
@@ -35,15 +42,8 @@ from lms.djangoapps.certificates.models import (
    CertificateWhitelist,
    GeneratedCertificate
 )
-from class_dashboard.dashboard_data import get_array_section_has_problem, get_section_display_name
-from course_modes.models import CourseMode, CourseModesArchive
-from courseware.access import has_access
-from courseware.courses import get_course_by_id, get_studio_url
-from django_comment_client.utils import available_division_schemes, has_forum_access
-from django_comment_common.models import FORUM_ROLE_ADMINISTRATOR, CourseDiscussionSettings
-from edxmako.shortcuts import render_to_response
 from lms.djangoapps.courseware.module_render import get_module_by_usage_id
-from lms.djangoapps.grades.config.waffle import waffle_flags, WRITABLE_GRADEBOOK
+from lms.djangoapps.grades.config.waffle import WRITABLE_GRADEBOOK, waffle_flags
 from openedx.core.djangoapps.course_groups.cohorts import DEFAULT_COHORT_NAME, get_course_cohorts, is_course_cohorted
 from openedx.core.djangoapps.site_configuration import helpers as configuration_helpers
 from openedx.core.djangoapps.verified_track_content.models import VerifiedTrackCohortedCourse
@@ -52,7 +52,7 @@ from openedx.core.lib.url_utils import quote_slashes
 from openedx.core.lib.xblock_utils import wrap_xblock
 from shoppingcart.models import Coupon, CourseRegCodeItem, PaidCourseRegistration
 from student.models import CourseEnrollment
-from student.roles import CourseFinanceAdminRole, CourseSalesAdminRole, CourseStaffRole, CourseInstructorRole
+from student.roles import CourseFinanceAdminRole, CourseInstructorRole, CourseSalesAdminRole, CourseStaffRole
 from util.json_request import JsonResponse
 from xmodule.html_module import HtmlDescriptor
 from xmodule.modulestore.django import modulestore
@@ -159,7 +159,7 @@ def instructor_dashboard_2(request, course_id):
            unicode(course_key), len(paid_modes)
        )

-    if settings.FEATURES.get('INDIVIDUAL_DUE_DATES') and access['instructor']:
+    if access['instructor']:
        sections.insert(3, _section_extensions(course))

    # Gate access to course email by feature flag & by course-specific authorization
--- a/lms/djangoapps/instructor/views/tools.py
+++ b/lms/djangoapps/instructor/views/tools.py
@@ -2,26 +2,18 @@
 Tools for the instructor dashboard
 """
 import json
+import operator

 import dateutil
 from django.contrib.auth.models import User
 from django.http import HttpResponseBadRequest
-from pytz import UTC
 from django.utils.translation import ugettext as _
 from opaque_keys.edx.keys import UsageKey
-from six import text_type, string_types
+from pytz import UTC
+from six import string_types, text_type

-from courseware.models import StudentFieldOverride
-from lms.djangoapps.courseware.field_overrides import disable_overrides
-from lms.djangoapps.courseware.student_field_overrides import (
-    clear_override_for_user,
-    get_override_for_user,
-    override_field_for_user,
-)
+from edx_when import api
 from student.models import get_user_by_username_or_email
-from xmodule.fields import Date
-
-DATE_FIELD = Date()


 class DashboardError(Exception):
@@ -158,29 +150,20 @@ def title_or_url(node):
    return title


-def set_due_date_extension(course, unit, student, due_date):
+def set_due_date_extension(course, unit, student, due_date, actor=None):
    """
    Sets a due date extension. Raises DashboardError if the unit or extended
    due date is invalid.
    """
    if due_date:
-        # Check that the new due date is valid:
-        with disable_overrides():
-            original_due_date = getattr(unit, 'due', None)
-
-        if not original_due_date:
+        try:
+            api.set_date_for_block(course.id, unit.location, 'due', due_date, user=student, reason=None, actor=actor)
+        except api.MissingDateError:
            raise DashboardError(_(u"Unit {0} has no due date to extend.").format(unit.location))
-        if due_date < original_due_date:
+        except api.InvalidDateError:
            raise DashboardError(_("An extended due date must be later than the original due date."))
-
-        override_field_for_user(student, unit, 'due', due_date)
-
    else:
-        # We are deleting a due date extension. Check that it exists:
-        if not get_override_for_user(student, unit, 'due'):
-            raise DashboardError(_("No due date extension is set for that student and unit."))
-
-        clear_override_for_user(student, unit, 'due')
+        api.set_date_for_block(course.id, unit.location, 'due', None, user=student, reason=None, actor=actor)


 def dump_module_extensions(course, unit):
@@ -188,20 +171,12 @@ def dump_module_extensions(course, unit):
    Dumps data about students with due date extensions for a particular module,
    specified by 'url', in a particular course.
    """
-    data = []
    header = [_("Username"), _("Full Name"), _("Extended Due Date")]
-    query = StudentFieldOverride.objects.filter(
-        course_id=course.id,
-        location=unit.location,
-        field='due')
-    for override in query:
-        due = DATE_FIELD.from_json(json.loads(override.value))
-        due = due.strftime(u"%Y-%m-%d %H:%M")
-        fullname = override.student.profile.name
-        data.append(dict(zip(
-            header,
-            (override.student.username, fullname, due))))
-    data.sort(key=lambda x: x[header[0]])
+    data = []
+    for username, fullname, due_date in api.get_overrides_for_block(course.id, unit.location):
+        due_date = due_date.strftime(u'%Y-%m-%d %H:%M')
+        data.append(dict(zip(header, (username, fullname, due_date))))
+    data.sort(key=operator.itemgetter(_("Username")))
    return {
        "header": header,
        "title": _(u"Users with due date extensions for {0}").format(
@@ -219,18 +194,16 @@ def dump_student_extensions(course, student):
    header = [_("Unit"), _("Extended Due Date")]
    units = get_units_with_due_date(course)
    units = {u.location: u for u in units}
-    query = StudentFieldOverride.objects.filter(
-        course_id=course.id,
-        student=student,
-        field='due')
+    query = api.get_overrides_for_user(course.id, student)
    for override in query:
-        location = override.location.replace(course_key=course.id)
+        location = override['location'].replace(course_key=course.id)
        if location not in units:
            continue
-        due = DATE_FIELD.from_json(json.loads(override.value))
+        due = override['actual_date']
        due = due.strftime(u"%Y-%m-%d %H:%M")
        title = title_or_url(units[location])
        data.append(dict(zip(header, (title, due))))
+    data.sort(key=operator.itemgetter(_("Unit")))
    return {
        "header": header,
        "title": _(u"Due date extensions for {0} {1} ({2})").format(
--- a/openedx/features/course_experience/tests/views/test_course_home.py
+++ b/openedx/features/course_experience/tests/views/test_course_home.py
@@ -213,7 +213,7 @@ class TestCourseHomePage(CourseHomePageTestCase):

        # Fetch the view and verify the query counts
        # TODO: decrease query count as part of REVO-28
-        with self.assertNumQueries(89, table_blacklist=QUERY_COUNT_TABLE_BLACKLIST):
+        with self.assertNumQueries(91, table_blacklist=QUERY_COUNT_TABLE_BLACKLIST):
            with check_mongo_calls(4):
                url = course_home_url(self.course)
                self.client.get(url)
--- a/openedx/features/course_experience/tests/views/test_course_updates.py
+++ b/openedx/features/course_experience/tests/views/test_course_updates.py
@@ -130,7 +130,7 @@ class TestCourseUpdatesPage(SharedModuleStoreTestCase):

        # Fetch the view and verify that the query counts haven't changed
        # TODO: decrease query count as part of REVO-28
-        with self.assertNumQueries(50, table_blacklist=QUERY_COUNT_TABLE_BLACKLIST):
+        with self.assertNumQueries(52, table_blacklist=QUERY_COUNT_TABLE_BLACKLIST):
            with check_mongo_calls(4):
                url = course_updates_url(self.course)
                self.client.get(url)
--- a/openedx/tests/settings.py
+++ b/openedx/tests/settings.py
@@ -88,6 +88,7 @@ INSTALLED_APPS = (
    'milestones',
    'celery_utils',
    'waffle',
+    'edx_when',

    # Django 1.11 demands to have imported models supported by installed apps.
    'completion',
--- a/requirements/edx/base.in
+++ b/requirements/edx/base.in
@@ -85,6 +85,7 @@ edx-rest-api-client
 edx-search
 edx-submissions
 edx-user-state-client
+edx-when
 edxval
 enum34==1.1.6                       # Backport of Enum from Python 3.4+
 event-tracking
--- a/requirements/edx/base.txt
+++ b/requirements/edx/base.txt
@@ -125,6 +125,7 @@ edx-rest-api-client==1.9.2
 edx-search==1.2.2
 edx-submissions==2.1.1
 edx-user-state-client==1.0.4
+edx-when==0.1.1
 edxval==1.1.25
 elasticsearch==1.9.0      # via edx-search
 enum34==1.1.6
--- a/requirements/edx/development.txt
+++ b/requirements/edx/development.txt
@@ -148,6 +148,7 @@ edx-search==1.2.2
 edx-sphinx-theme==1.4.0
 edx-submissions==2.1.1
 edx-user-state-client==1.0.4
+edx-when==0.1.1
 edxval==1.1.25
 elasticsearch==1.9.0
 entrypoints==0.3
--- a/requirements/edx/testing.txt
+++ b/requirements/edx/testing.txt
@@ -143,6 +143,7 @@ edx-rest-api-client==1.9.2
 edx-search==1.2.2
 edx-submissions==2.1.1
 edx-user-state-client==1.0.4
+edx-when==0.1.1
 edxval==1.1.25
 elasticsearch==1.9.0
 entrypoints==0.3          # via flake8