  
  class RouterTestCase(TestCase):
      multi_db = True
  
      def setUp(self):
          # Make the 'other' database appear to be a replica of the 'default'
          self.old_routers = router.routers
          router.routers = [TestRouter()]
  
      def tearDown(self):
          # Restore the 'other' database as an independent database
          router.routers = self.old_routers
  
      def test_db_selection(self):
          "Check that querysets obey the router for db suggestions"
          self.assertEqual(Book.objects.db, 'other')
          self.assertEqual(Book.objects.all().db, 'other')
  
 
</s> remove     def setUp(self):
        # Make the 'other' database appear to be a replica of the 'default'
        self.old_routers = router.routers
        router.routers = [MigrateNothingRouter()]

    def tearDown(self):
        # Restore the 'other' database as an independent database
        router.routers = self.old_routers

 </s> add  </s> remove         self.old_routers = router.routers
        router.routers = [TestRouter()]

 </s> add  </s> remove     def setUp(self):
        self.old_routers = router.routers
        router.routers = [OtherRouter()]

    def tearDown(self):
        router.routers = self.old_routers

 </s> add  </s> remove     def setUp(self):
        self._old_routers = router.routers
        router.routers = [TestRouter()]

    def tearDown(self):
        router.routers = self._old_routers
 </s> add 
  
  class RouterTestCase(TestCase):
      multi_db = True
  









      def test_db_selection(self):
          "Check that querysets obey the router for db suggestions"
          self.assertEqual(Book.objects.db, 'other')
          self.assertEqual(Book.objects.all().db, 'other')
  
keep keep keep keep replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Replaced router.routers usage with override_settings(DATABASE_ROUTERS); refs #23933. 
tests/multiple_database/tests.py