title: Django AttributeError: object has no attribute 'assertContains'
body: <p>I'm trying Django test fixtures from the official documentation, but my test class can't find assertContains.</p>
  
  <pre><code>from django.utils import unittest
  from django.test import Client
  
  class SimpleTest(unittest.TestCase):
      def setUp(self):
          self.client = Client()
  
      def test_details(self):
          response = self.client.post('/register',
                                      {'username': '123',
                                       'password': '123',
                                      follow=True)
          self.assertEqual(response.status_code, 200)
  
          self.assertContains(response, "Logout")
          self.assertNotContains(response, "Login")
  </code></pre>