Deprecate WaffleSwitch.override* methods

This allows us to get rid of the custom WaffleSwitch and
WaffleSwitchNamespace classes from waffle_utils in favour of
edx_toggles.toggles classes.

lms/djangoapps/grades/config/waffle.py

@@ -4,7 +4,12 @@ waffle switches for the Grades app.
 """
 
 
-from openedx.core.djangoapps.waffle_utils import CourseWaffleFlag, WaffleFlagNamespace, WaffleSwitchNamespace
+from openedx.core.djangoapps.waffle_utils import (
+    CourseWaffleFlag,
+    WaffleFlagNamespace,
+    WaffleSwitch,
+    WaffleSwitchNamespace
+)
 
 # Namespace
 WAFFLE_NAMESPACE = u'grades'
@@ -81,6 +86,16 @@ def waffle():
     return WaffleSwitchNamespace(name=WAFFLE_NAMESPACE, log_prefix=u'Grades: ')
 
 
+def waffle_switch(name):
+    """
+    Return the corresponding namespaced waffle switch.
+
+    WARNING: do not replicate this pattern. Instead of declaring waffle switch names as strings, you should create
+    WaffleSwitch objects as top-level constants.
+    """
+    return WaffleSwitch(waffle(), name, module_name=__name__)
+
+
 def waffle_flags():
     """
     Returns the namespaced, cached, audited Waffle flags dictionary for Grades.

lms/djangoapps/grades/tests/test_course_grade.py

@@ -4,13 +4,14 @@ from crum import set_current_request
 from django.conf import settings
 from mock import patch
 
+from edx_toggles.toggles.testutils import override_waffle_switch
 from openedx.core.djangolib.testing.utils import get_mock_request
 from student.models import CourseEnrollment
 from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 
-from ..config.waffle import ASSUME_ZERO_GRADE_IF_ABSENT, waffle
+from ..config.waffle import ASSUME_ZERO_GRADE_IF_ABSENT, waffle_switch
 from ..course_data import CourseData
 from ..course_grade import ZeroCourseGrade
 from ..course_grade_factory import CourseGradeFactory
@@ -31,7 +32,7 @@ class ZeroGradeTest(GradeTestBase):
         """
         Creates a ZeroCourseGrade and ensures it's empty.
         """
-        with waffle().override(ASSUME_ZERO_GRADE_IF_ABSENT, active=assume_zero_enabled):
+        with override_waffle_switch(waffle_switch(ASSUME_ZERO_GRADE_IF_ABSENT), active=assume_zero_enabled):
             course_data = CourseData(self.request.user, structure=self.course_structure)
             chapter_grades = ZeroCourseGrade(self.request.user, course_data).chapter_grades
             for chapter in chapter_grades:
@@ -46,7 +47,7 @@ class ZeroGradeTest(GradeTestBase):
         """
         Creates a zero course grade and ensures that null scores aren't included in the section problem scores.
         """
-        with waffle().override(ASSUME_ZERO_GRADE_IF_ABSENT, active=assume_zero_enabled):
+        with override_waffle_switch(waffle_switch(ASSUME_ZERO_GRADE_IF_ABSENT), active=assume_zero_enabled):
             with patch('lms.djangoapps.grades.subsection_grade.get_score', return_value=None):
                 course_data = CourseData(self.request.user, structure=self.course_structure)
                 chapter_grades = ZeroCourseGrade(self.request.user, course_data).chapter_grades

lms/djangoapps/grades/tests/test_course_grade_factory.py

@@ -9,7 +9,7 @@ import ddt
 from django.conf import settings
 from mock import patch
 from six import text_type
-
+from edx_toggles.toggles.testutils import override_waffle_switch
 from lms.djangoapps.courseware.access import has_access
 from lms.djangoapps.grades.config.tests.utils import persistent_grades_feature_flags
 from openedx.core.djangoapps.content.block_structure.factory import BlockStructureFactory
@@ -17,7 +17,7 @@ from student.tests.factories import UserFactory
 from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 
-from ..config.waffle import ASSUME_ZERO_GRADE_IF_ABSENT, waffle
+from ..config.waffle import ASSUME_ZERO_GRADE_IF_ABSENT, waffle_switch
 from ..course_grade import CourseGrade, ZeroCourseGrade
 from ..course_grade_factory import CourseGradeFactory
 from ..subsection_grade import ReadSubsectionGrade, ZeroSubsectionGrade
@@ -132,7 +132,7 @@ class TestCourseGradeFactory(GradeTestBase):
     @ddt.data(*itertools.product((True, False), (True, False)))
     @ddt.unpack
     def test_read_zero(self, assume_zero_enabled, create_if_needed):
-        with waffle().override(ASSUME_ZERO_GRADE_IF_ABSENT, active=assume_zero_enabled):
+        with override_waffle_switch(waffle_switch(ASSUME_ZERO_GRADE_IF_ABSENT), active=assume_zero_enabled):
             grade_factory = CourseGradeFactory()
             course_grade = grade_factory.read(self.request.user, self.course, create_if_needed=create_if_needed)
             if create_if_needed or assume_zero_enabled: