Refs #25745 -- Isolated an order_with_respect_to test.

tests/order_with_respect_to/tests.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 
 from operator import attrgetter
 
+from django.apps.registry import Apps
 from django.db import models
 from django.test import TestCase
 
@@ -95,9 +96,11 @@ class OrderWithRespectToTests2(TestCase):
         self.assertSequenceEqual(p1.get_post_order(), [p1_1.pk, p1_2.pk, p1_3.pk])
 
     def test_duplicate_order_field(self):
+        test_apps = Apps(['order_with_respect_to'])
 
         class Bar(models.Model):
             class Meta:
+                apps = test_apps
                 app_label = 'order_with_respect_to'
 
         class Foo(models.Model):
@@ -106,6 +109,7 @@ class OrderWithRespectToTests2(TestCase):
 
             class Meta:
                 order_with_respect_to = 'bar'
+                apps = test_apps
                 app_label = 'order_with_respect_to'
 
         count = 0