text: from __future__ import unicode_literals
  
  import os
  import sys
  
  from django.conf import settings
  from django.core.management import call_command
  from django.db.models.loading import cache, load_app
  from django.test import TestCase, TransactionTestCase
  from django.test.utils import override_settings
  from django.utils._os import upath
  
  from .models import (ConcreteModel, ConcreteModelSubclass,
      ConcreteModelSubclassProxy)
  
  
  @override_settings(INSTALLED_APPS=('app1', 'app2'))
  class ProxyModelInheritanceTests(TransactionTestCase):
      """
      Proxy model inheritance across apps can result in migrate not creating the table
      for the proxied model (as described in #12286).  This test creates two dummy
      apps and calls migrate, then verifies that the table has been created.
      """
  
      available_apps = []
  
      def setUp(self):
          self.old_sys_path = sys.path[:]
          sys.path.append(os.path.dirname(os.path.abspath(upath(__file__))))
          for app in settings.INSTALLED_APPS:
              load_app(app)
  
      def tearDown(self):
          sys.path = self.old_sys_path
          del cache.app_store[cache.app_labels['app1']]
          del cache.app_store[cache.app_labels['app2']]
          del cache.app_labels['app1']
          del cache.app_labels['app2']
          del cache.app_models['app1']
          del cache.app_models['app2']
  
      def test_table_exists(self):
          try:
              cache.set_available_apps(settings.INSTALLED_APPS)
              call_command('migrate', verbosity=0)
          finally:
              cache.unset_available_apps()
          from .app1.models import ProxyModel
          from .app2.models import NiceModel
          self.assertEqual(NiceModel.objects.all().count(), 0)
          self.assertEqual(ProxyModel.objects.all().count(), 0)
  
  
  class MultiTableInheritanceProxyTest(TestCase):
  
      def test_model_subclass_proxy(self):
          """
          Deleting an instance of a model proxying a multi-table inherited
          subclass should cascade delete down the whole inheritance chain (see
          #18083).
  
          """
          instance = ConcreteModelSubclassProxy.objects.create()
          instance.delete()
          self.assertEqual(0, ConcreteModelSubclassProxy.objects.count())
          self.assertEqual(0, ConcreteModelSubclass.objects.count())
          self.assertEqual(0, ConcreteModel.objects.count())
  