new_contents: from django.db import models
  from django.test import TestCase
  
  from ..models import SearchMetaBase, OnlineBase, PublishedBase
  from ..sitemaps import (BaseSitemap, SearchMetaBaseSitemap, OnlineBaseSitemap,
                          PublishedBaseSitemap, SitemapRegistrationError,
                          register, registered_sitemaps)
  
  
  class SitemapModel(models.Model):
      pass
  
  
  class SearchMetaBaseModel(SearchMetaBase):
      pass
  
  
  class OnlineBaseModel(OnlineBase):
      pass
  
  
  class PublishedBaseModel(PublishedBase):
      pass
  
  
  class Object(object):
  
      sitemap_priority = 1
  
      def __init__(self, *args, **kwargs):
          self.sitemap_changefreq = kwargs.get('freq', 1)
  
      def get_sitemap_changefreq_display(self):
          return 'Always'
  
  
  class TestSitemaps(TestCase):
  
      def test_searchmetabasesitemap_changefreq(self):
          sitemap = SearchMetaBaseSitemap()
          obj = Object()
          self.assertEqual(sitemap.changefreq(obj), 'always')
  
          obj = Object(freq=None)
          self.assertIsNone(sitemap.changefreq(obj))
  
      def test_searchmetabasesitemap_priority(self):
          sitemap = SearchMetaBaseSitemap()
          obj = Object()
          self.assertEqual(sitemap.priority(obj), 1)
  
      def test_register(self):
          register(SitemapModel)
  
          with self.assertRaises(SitemapRegistrationError):
              register(SitemapModel)
  
          self.assertEqual(
              registered_sitemaps['cms-sitemapmodel'].__bases__[0],
              BaseSitemap
          )
  
          register(SearchMetaBaseModel)
  
          self.assertEqual(
              registered_sitemaps['cms-searchmetabasemodel'].__bases__[0],
              SearchMetaBaseSitemap
          )
  
          register(OnlineBaseModel)
  
          self.assertEqual(
              registered_sitemaps['cms-onlinebasemodel'].__bases__[0],
              OnlineBaseSitemap
          )
  
          register(PublishedBaseModel)
  
          self.assertEqual(
              registered_sitemaps['cms-publishedbasemodel'].__bases__[0],
              PublishedBaseSitemap
          )
  
subject: Add tests for `cms.sitemaps`.