text: from __future__ import unicode_literals
  
  import urllib
  
  from django.db import models
  from django.contrib.contenttypes.models import ContentType
  from django.contrib.contenttypes.views import shortcut
  from django.contrib.sites.models import Site
  from django.http import HttpRequest, Http404
  from django.test import TestCase
  from django.utils.encoding import smart_str
  
  
  class FooWithoutUrl(models.Model):
      """
      Fake model not defining ``get_absolute_url`` for
      :meth:`ContentTypesTests.test_shortcut_view_without_get_absolute_url`"""
      name = models.CharField(max_length=30, unique=True)
  
      def __unicode__(self):
          return self.name
  
  
  class FooWithUrl(FooWithoutUrl):
      """
      Fake model defining ``get_absolute_url`` for
      :meth:`ContentTypesTests.test_shortcut_view`
      """
  
      def get_absolute_url(self):
          return "/users/%s/" % urllib.quote(smart_str(self.name))
  
  class FooWithBrokenAbsoluteUrl(FooWithoutUrl):
      """
      Fake model defining a ``get_absolute_url`` method containing an error
      """
  
      def get_absolute_url(self):
          return "/users/%s/" % self.unknown_field
  
  class ContentTypesTests(TestCase):
  
      def setUp(self):
          self.old_Site_meta_installed = Site._meta.installed
          ContentType.objects.clear_cache()
  
      def tearDown(self):
          Site._meta.installed = self.old_Site_meta_installed
          ContentType.objects.clear_cache()
  
      def test_lookup_cache(self):
          """
          Make sure that the content type cache (see ContentTypeManager)
          works correctly. Lookups for a particular content type -- by model, ID
          or natural key -- should hit the database only on the first lookup.
          """
  
          # At this point, a lookup for a ContentType should hit the DB
          with self.assertNumQueries(1):
              ContentType.objects.get_for_model(ContentType)
  
          # A second hit, though, won't hit the DB, nor will a lookup by ID
          # or natural key
          with self.assertNumQueries(0):
              ct = ContentType.objects.get_for_model(ContentType)
          with self.assertNumQueries(0):
              ContentType.objects.get_for_id(ct.id)
          with self.assertNumQueries(0):
              ContentType.objects.get_by_natural_key('contenttypes',
                                                     'contenttype')
  
          # Once we clear the cache, another lookup will again hit the DB
          ContentType.objects.clear_cache()
          with self.assertNumQueries(1):
              ContentType.objects.get_for_model(ContentType)
  
          # The same should happen with a lookup by natural key
          ContentType.objects.clear_cache()
          with self.assertNumQueries(1):
              ContentType.objects.get_by_natural_key('contenttypes',
                                                     'contenttype')
          # And a second hit shouldn't hit the DB
          with self.assertNumQueries(0):
              ContentType.objects.get_by_natural_key('contenttypes',
                                                     'contenttype')
  
      def test_get_for_models_empty_cache(self):
          # Empty cache.
          with self.assertNumQueries(1):
              cts = ContentType.objects.get_for_models(ContentType, FooWithUrl)
          self.assertEqual(cts, {
              ContentType: ContentType.objects.get_for_model(ContentType),
              FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
          })
  
      def test_get_for_models_partial_cache(self):
          # Partial cache
          ContentType.objects.get_for_model(ContentType)
          with self.assertNumQueries(1):
              cts = ContentType.objects.get_for_models(ContentType, FooWithUrl)
          self.assertEqual(cts, {
              ContentType: ContentType.objects.get_for_model(ContentType),
              FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
          })
  
      def test_get_for_models_full_cache(self):
          # Full cache
          ContentType.objects.get_for_model(ContentType)
          ContentType.objects.get_for_model(FooWithUrl)
          with self.assertNumQueries(0):
              cts = ContentType.objects.get_for_models(ContentType, FooWithUrl)
          self.assertEqual(cts, {
              ContentType: ContentType.objects.get_for_model(ContentType),
              FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
          })
  
      def test_shortcut_view(self):
          """
          Check that the shortcut view (used for the admin "view on site"
          functionality) returns a complete URL regardless of whether the sites
          framework is installed
          """
  
          request = HttpRequest()
          request.META = {
              "SERVER_NAME": "Example.com",
              "SERVER_PORT": "80",
          }
          user_ct = ContentType.objects.get_for_model(FooWithUrl)
          obj = FooWithUrl.objects.create(name="john")
  
          if Site._meta.installed:
              current_site = Site.objects.get_current()
              response = shortcut(request, user_ct.id, obj.id)
              self.assertEqual("http://%s/users/john/" % current_site.domain,
                               response._headers.get("location")[1])
  
          Site._meta.installed = False
          response = shortcut(request, user_ct.id, obj.id)
          self.assertEqual("http://Example.com/users/john/",
                           response._headers.get("location")[1])
  
      def test_shortcut_view_without_get_absolute_url(self):
          """
          Check that the shortcut view (used for the admin "view on site"
          functionality) returns 404 when get_absolute_url is not defined.
          """
  
          request = HttpRequest()
          request.META = {
              "SERVER_NAME": "Example.com",
              "SERVER_PORT": "80",
          }
          user_ct = ContentType.objects.get_for_model(FooWithoutUrl)
          obj = FooWithoutUrl.objects.create(name="john")
  
          self.assertRaises(Http404, shortcut, request, user_ct.id, obj.id)
  
      def test_shortcut_view_with_broken_get_absolute_url(self):
          """
          Check that the shortcut view does not catch an AttributeError raised
          by the model's get_absolute_url method.
          Refs #8997.
          """
          request = HttpRequest()
          request.META = {
              "SERVER_NAME": "Example.com",
              "SERVER_PORT": "80",
          }
          user_ct = ContentType.objects.get_for_model(FooWithBrokenAbsoluteUrl)
          obj = FooWithBrokenAbsoluteUrl.objects.create(name="john")
  
          self.assertRaises(AttributeError, shortcut, request, user_ct.id, obj.id)
  
      def test_missing_model(self):
          """
          Ensures that displaying content types in admin (or anywhere) doesn't
          break on leftover content type records in the DB for which no model
          is defined anymore.
          """
          ct = ContentType.objects.create(
              name = 'Old model',
              app_label = 'contenttypes',
              model = 'OldModel',
          )
          self.assertEqual(unicode(ct), 'Old model')
  