tests: Use function to create realm rather than django ORM.

This commit makes changes in backend tests to use
`do_create_realm` function to create realm.

corporate/tests/test_stripe.py

@@ -3650,7 +3650,11 @@ class StripeTest(StripeTestCase):
             num_invoices: Optional[int] = None,
         ) -> Tuple[Realm, Optional[Customer], Optional[CustomerPlan], List[stripe.Invoice]]:
             realm_string_id = "realm_" + str(random.randrange(1, 1000000))
-            realm = Realm.objects.create(string_id=realm_string_id)
+            realm = do_create_realm(
+                string_id=realm_string_id,
+                name=realm_string_id,
+                plan_type=Realm.PLAN_TYPE_SELF_HOSTED,
+            )
             users = []
             for i in range(users_to_create):
                 user = UserProfile.objects.create(

zerver/tests/test_audit_log.py

@@ -11,6 +11,7 @@ from zerver.actions.bots import (
     do_change_default_events_register_stream,
     do_change_default_sending_stream,
 )
+from zerver.actions.create_realm import do_create_realm
 from zerver.actions.create_user import (
     do_activate_mirror_dummy_user,
     do_create_user,
@@ -70,7 +71,6 @@ from zerver.lib.streams import create_stream_if_needed
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import get_test_image_file
 from zerver.lib.types import LinkifierDict, RealmPlaygroundDict
-from zerver.lib.user_groups import create_system_user_groups_for_realm
 from zerver.lib.utils import assert_is_not_none
 from zerver.models import (
     EmojiInfo,
@@ -1058,9 +1058,8 @@ class TestRealmAuditLog(ZulipTestCase):
         )
 
     def test_system_user_groups_creation(self) -> None:
-        realm = Realm.objects.create(string_id="test", name="foo")
         now = timezone_now()
-        create_system_user_groups_for_realm(realm)
+        realm = do_create_realm(string_id="test", name="foo")
 
         # The expected number of system user group is the total number of roles
         # from UserGroup.SYSTEM_USER_GROUP_ROLE_MAP in addition to