Convert CohortedTestCase to use SharedModuleStoreTestCase.

Some low hanging fruit optimization of forums tests.

lms/djangoapps/django_comment_client/tests/utils.py

@@ -8,23 +8,32 @@ from django_comment_common.models import Role
 from django_comment_common.utils import seed_permissions_roles
 from student.tests.factories import CourseEnrollmentFactory, UserFactory
 from xmodule.modulestore.tests.factories import CourseFactory
-from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
+from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
 
 
-class CohortedTestCase(ModuleStoreTestCase):
+class CohortedTestCase(SharedModuleStoreTestCase):
     """
     Sets up a course with a student, a moderator and their cohorts.
     """
+    @classmethod
     @patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
-    def setUp(self):
-        super(CohortedTestCase, self).setUp()
-
-        self.course = CourseFactory.create(
+    def setUpClass(cls):
+        super(CohortedTestCase, cls).setUpClass()
+        cls.course = CourseFactory.create(
             cohort_config={
                 "cohorted": True,
                 "cohorted_discussions": ["cohorted_topic"]
             }
         )
+        cls.course.discussion_topics["cohorted topic"] = {"id": "cohorted_topic"}
+        cls.course.discussion_topics["non-cohorted topic"] = {"id": "non_cohorted_topic"}
+        fake_user_id = 1
+        cls.store.update_item(cls.course, fake_user_id)
+
+    @patch.dict("django.conf.settings.FEATURES", {"ENABLE_DISCUSSION_SERVICE": True})
+    def setUp(self):
+        super(CohortedTestCase, self).setUp()
+
         self.student_cohort = CohortFactory.create(
             name="student_cohort",
             course_id=self.course.id
@@ -33,10 +42,6 @@ class CohortedTestCase(ModuleStoreTestCase):
             name="moderator_cohort",
             course_id=self.course.id
         )
-        self.course.discussion_topics["cohorted topic"] = {"id": "cohorted_topic"}
-        self.course.discussion_topics["non-cohorted topic"] = {"id": "non_cohorted_topic"}
-        self.store.update_item(self.course, self.user.id)
-
         seed_permissions_roles(self.course.id)
         self.student = UserFactory.create()
         self.moderator = UserFactory.create()