text: from __future__ import unicode_literals
  
  from django.contrib import admin
  from django.contrib.admin.decorators import register
  from django.contrib.admin.sites import site
  from django.core.exceptions import ImproperlyConfigured
  from django.test import TestCase
  
  from .models import Person, Place, Location, Traveler
  
  
  class NameAdmin(admin.ModelAdmin):
      list_display = ['name']
      save_on_top = True
  
  
  class CustomSite(admin.AdminSite):
      pass
  
  
  class TestRegistration(TestCase):
      def setUp(self):
          self.site = admin.AdminSite()
  
      def test_bare_registration(self):
          self.site.register(Person)
          self.assertTrue(
              isinstance(self.site._registry[Person], admin.options.ModelAdmin)
          )
  
      def test_registration_with_model_admin(self):
          self.site.register(Person, NameAdmin)
          self.assertTrue(
              isinstance(self.site._registry[Person], NameAdmin)
          )
  
      def test_prevent_double_registration(self):
          self.site.register(Person)
          self.assertRaises(admin.sites.AlreadyRegistered,
                            self.site.register,
                            Person)
  
      def test_registration_with_star_star_options(self):
          self.site.register(Person, search_fields=['name'])
          self.assertEqual(self.site._registry[Person].search_fields, ['name'])
  
      def test_star_star_overrides(self):
          self.site.register(Person, NameAdmin,
                             search_fields=["name"], list_display=['__str__'])
          self.assertEqual(self.site._registry[Person].search_fields, ['name'])
          self.assertEqual(self.site._registry[Person].list_display,
                           ['__str__'])
          self.assertTrue(self.site._registry[Person].save_on_top)
  
      def test_iterable_registration(self):
          self.site.register([Person, Place], search_fields=['name'])
          self.assertTrue(
              isinstance(self.site._registry[Person], admin.options.ModelAdmin)
          )
          self.assertEqual(self.site._registry[Person].search_fields, ['name'])
          self.assertTrue(
              isinstance(self.site._registry[Place], admin.options.ModelAdmin)
          )
          self.assertEqual(self.site._registry[Place].search_fields, ['name'])
  
      def test_abstract_model(self):
          """
          Exception is raised when trying to register an abstract model.
          Refs #12004.
          """
          self.assertRaises(ImproperlyConfigured, self.site.register, Location)
  
  
  class TestRegistrationDecorator(TestCase):
      """
      Tests the register decorator in admin.decorators
  
      For clarity:
  
          @register(Person)
          class AuthorAdmin(ModelAdmin):
              pass
  
      is functionally equal to (the way it is written in these tests):
  
          AuthorAdmin = register(Person)(AuthorAdmin)
      """
      def setUp(self):
          self.default_site = site
          self.custom_site = CustomSite()
  
      def test_basic_registration(self):
          register(Person)(NameAdmin)
          self.assertTrue(
              isinstance(self.default_site._registry[Person],
                         admin.options.ModelAdmin)
          )
  
      def test_custom_site_registration(self):
          register(Person, site=self.custom_site)(NameAdmin)
          self.assertTrue(
              isinstance(self.custom_site._registry[Person],
                         admin.options.ModelAdmin)
          )
  
      def test_multiple_registration(self):
          register(Traveler, Place)(NameAdmin)
          self.assertTrue(
              isinstance(self.default_site._registry[Traveler],
                         admin.options.ModelAdmin)
          )
          self.assertTrue(
              isinstance(self.default_site._registry[Place],
                         admin.options.ModelAdmin)
          )
  
      def test_wrapped_class_not_a_model_admin(self):
          self.assertRaisesMessage(ValueError, 'Wrapped class must sublcass ModelAdmin.',
              register(Person), CustomSite)
  
      def test_custom_site_not_an_admin_site(self):
          self.assertRaisesMessage(ValueError, 'site must subclass AdminSite',
              register(Person, site=Traveler), NameAdmin)
  