old_contents: import json
  from django.test import TestCase
  
  
  class PreviewResourceTestCase(TestCase):
      def test_get(self):
          response = self.client.get('/api/data/preview/',
              HTTP_ACCEPT='application/json')
          self.assertEqual(response.status_code, 200)
          self.assertEqual(response['Content-Type'], 'application/json')
          self.assertEqual(json.loads(response.content), {
              '_links': {
                  'self': {
                      'href': 'http://testserver/api/data/preview/?limit=20&page=1',
                  },
                  'base': {
                      'href': 'http://testserver/api/data/preview/',
                  }
              },
              'keys': [],
              'object_count': 0,
              'object_name': 'employee',
              'object_name_plural': 'employees',
              'objects': [],
              'page_num': 1,
              'num_pages': 1,
              'limit': 20,
          })
  
new_contents: import json
  from django.contrib.auth.models import User
  from django.test import TestCase
  
  
  class PreviewResourceTestCase(TestCase):
      def test_get(self):
          response = self.client.get('/api/data/preview/',
              HTTP_ACCEPT='application/json')
          self.assertEqual(response.status_code, 200)
          self.assertEqual(response['Content-Type'], 'application/json')
          self.assertEqual(json.loads(response.content), {
              '_links': {
                  'self': {
                      'href': 'http://testserver/api/data/preview/?limit=20&page=1',
                  },
                  'base': {
                      'href': 'http://testserver/api/data/preview/',
                  }
              },
              'keys': [],
              'object_count': 0,
              'object_name': 'employee',
              'object_name_plural': 'employees',
              'objects': [],
              'page_num': 1,
              'num_pages': 1,
              'limit': 20,
          })
  
      def test_get_with_user(self):
          self.user = User.objects.create_user(username='test', password='test')
          self.client.login(username='test', password='test')
  
          response = self.client.get('/api/data/preview/',
              HTTP_ACCEPT='application/json')
          self.assertEqual(response.status_code, 200)
          self.assertEqual(response['Content-Type'], 'application/json')
          self.assertEqual(json.loads(response.content), {
              '_links': {
                  'self': {
                      'href': 'http://testserver/api/data/preview/?limit=20&page=1',
                  },
                  'base': {
                      'href': 'http://testserver/api/data/preview/',
                  }
              },
              'keys': [],
              'object_count': 0,
              'object_name': 'employee',
              'object_name_plural': 'employees',
              'objects': [],
              'page_num': 1,
              'num_pages': 1,
              'limit': 20,
          })
  
subject: Add test to recreate error in this bug