From f92c96ef05acad66940e693255d39e5c807d4543 Mon Sep 17 00:00:00 2001
From: Tyler Hallada <thallada@edx.org>
Date: Wed, 2 Aug 2017 10:22:19 -0400
Subject: [PATCH] Add course flag and service for grade override

---
 lms/djangoapps/grades/config/waffle.py       | 20 +++++++++++++++++-
 lms/djangoapps/grades/services.py            |  5 +++++
 lms/djangoapps/grades/tests/test_services.py | 22 ++++++++++++++++++++
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/lms/djangoapps/grades/config/waffle.py b/lms/djangoapps/grades/config/waffle.py
index c5705ac491..6453a75e97 100644
--- a/lms/djangoapps/grades/config/waffle.py
+++ b/lms/djangoapps/grades/config/waffle.py
@@ -2,7 +2,7 @@
 This module contains various configuration settings via
 waffle switches for the Grades app.
 """
-from openedx.core.djangoapps.waffle_utils import WaffleSwitchNamespace
+from openedx.core.djangoapps.waffle_utils import WaffleSwitchNamespace, WaffleFlagNamespace, CourseWaffleFlag
 
 # Namespace
 WAFFLE_NAMESPACE = u'grades'
@@ -12,9 +12,27 @@ WRITE_ONLY_IF_ENGAGED = u'write_only_if_engaged'
 ASSUME_ZERO_GRADE_IF_ABSENT = u'assume_zero_grade_if_absent'
 ESTIMATE_FIRST_ATTEMPTED = u'estimate_first_attempted'
 
+# Course Flags
+REJECTED_EXAM_OVERRIDES_GRADE = u'rejected_exam_overrides_grade'
+
 
 def waffle():
     """
     Returns the namespaced, cached, audited Waffle class for Grades.
     """
     return WaffleSwitchNamespace(name=WAFFLE_NAMESPACE, log_prefix=u'Grades: ')
+
+
+def waffle_flags():
+    """
+    Returns the namespaced, cached, audited Waffle flags dictionary for Grades.
+    """
+    namespace = WaffleFlagNamespace(name=WAFFLE_NAMESPACE, log_prefix=u'Grades: ')
+    return {
+        # By default, enable rejected exam grade overrides. Can be disabled on a course-by-course basis.
+        REJECTED_EXAM_OVERRIDES_GRADE: CourseWaffleFlag(
+            namespace,
+            REJECTED_EXAM_OVERRIDES_GRADE,
+            flag_undefined_default=True
+        )
+    }
diff --git a/lms/djangoapps/grades/services.py b/lms/djangoapps/grades/services.py
index 387d86521d..cbc5521ac4 100644
--- a/lms/djangoapps/grades/services.py
+++ b/lms/djangoapps/grades/services.py
@@ -6,6 +6,7 @@ from opaque_keys.edx.keys import CourseKey, UsageKey
 from track.event_transaction_utils import create_new_event_transaction_id, set_event_transaction_type
 from util.date_utils import to_timestamp
 
+from .config.waffle import waffle_flags, REJECTED_EXAM_OVERRIDES_GRADE
 from .constants import ScoreDatabaseTableEnum
 from .models import PersistentSubsectionGrade, PersistentSubsectionGradeOverride
 
@@ -141,3 +142,7 @@ class GradesService(object):
                 score_db_table=ScoreDatabaseTableEnum.overrides
             )
         )
+
+    def should_override_grade_on_rejected_exam(self, course_key):
+        """Convienence function to return the state of the CourseWaffleFlag REJECTED_EXAM_OVERRIDES_GRADE"""
+        return waffle_flags()[REJECTED_EXAM_OVERRIDES_GRADE].is_enabled(course_key)
diff --git a/lms/djangoapps/grades/tests/test_services.py b/lms/djangoapps/grades/tests/test_services.py
index f6e8a05c2c..e41f1f72ce 100644
--- a/lms/djangoapps/grades/tests/test_services.py
+++ b/lms/djangoapps/grades/tests/test_services.py
@@ -12,9 +12,18 @@ from util.date_utils import to_timestamp
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 
+from ..config.waffle import REJECTED_EXAM_OVERRIDES_GRADE
 from ..constants import ScoreDatabaseTableEnum
 
 
+class MockWaffleFlag():
+    def __init__(self, state):
+        self.state = state
+
+    def is_enabled(self, course_key):
+        return self.state
+
+
 @ddt.ddt
 class GradesServiceTests(ModuleStoreTestCase):
     """
@@ -44,11 +53,17 @@ class GradesServiceTests(ModuleStoreTestCase):
         self.mock_create_id.return_value = 1
         self.type_patcher = patch('lms.djangoapps.grades.services.set_event_transaction_type')
         self.mock_set_type = self.type_patcher.start()
+        self.flag_patcher = patch('lms.djangoapps.grades.services.waffle_flags')
+        self.mock_waffle_flags = self.flag_patcher.start()
+        self.mock_waffle_flags.return_value = {
+            REJECTED_EXAM_OVERRIDES_GRADE: MockWaffleFlag(True)
+        }
 
     def tearDown(self):
         self.recalc_patcher.stop()
         self.id_patcher.stop()
         self.type_patcher.stop()
+        self.flag_patcher.stop()
 
     def subsection_grade_to_dict(self, grade):
         return {
@@ -218,3 +233,10 @@ class GradesServiceTests(ModuleStoreTestCase):
     @ddt.unpack
     def test_get_key(self, input_key, output_key, key_cls):
         self.assertEqual(_get_key(input_key, key_cls), output_key)
+
+    def test_should_override_grade_on_rejected_exam(self):
+        self.assertTrue(self.service.should_override_grade_on_rejected_exam('course-v1:edX+DemoX+Demo_Course'))
+        self.mock_waffle_flags.return_value = {
+            REJECTED_EXAM_OVERRIDES_GRADE: MockWaffleFlag(False)
+        }
+        self.assertFalse(self.service.should_override_grade_on_rejected_exam('course-v1:edX+DemoX+Demo_Course'))