          the REMOTE_USER header disappears during the same browser session.
          """
          User.objects.create(username='knownuser')
          # Known user authenticates
          response = self.client.get('/remote_user/', REMOTE_USER=self.known_user)
          self.assertEqual(response.context['user'].username, 'knownuser')
          # During the session, the REMOTE_USER header disappears. Should trigger logout.
          response = self.client.get('/remote_user/')
          self.assertEqual(response.context['user'].is_anonymous(), True)
          # verify the remoteuser middleware will not remove a user
 
</s> remove         response = self.client.get('/remote_user/', REMOTE_USER=self.known_user)
 </s> add         response = self.client.get('/remote_user/',
                                   **{self.header: self.known_user}) </s> remove         response = self.client.get('/remote_user/', REMOTE_USER='newuser')
 </s> add         response = self.client.get('/remote_user/', **{self.header: 'newuser'}) </s> remove         response = self.client.get('/remote_user/', REMOTE_USER='newuser')
 </s> add         response = self.client.get('/remote_user/', **{self.header: 'newuser'}) </s> remove         response = self.client.get('/remote_user/', REMOTE_USER=self.known_user2)
 </s> add         response = self.client.get('/remote_user/',
                                   **{self.header: self.known_user2})
        response = self.client.get('/remote_user/',
                                   **{self.header: self.known_user})
          the REMOTE_USER header disappears during the same browser session.
          """
          User.objects.create(username='knownuser')
          # Known user authenticates
        response = self.client.get('/remote_user/',
                                   **{self.header: self.known_user})
          self.assertEqual(response.context['user'].username, 'knownuser')
          # During the session, the REMOTE_USER header disappears. Should trigger logout.
          response = self.client.get('/remote_user/')
          self.assertEqual(response.context['user'].is_anonymous(), True)
          # verify the remoteuser middleware will not remove a user
keep keep keep keep replace keep keep keep keep keep
 Fixed #21250 -- Made HTTP auth user header configurable in tests

Currently, if the authentication mechanism uses a custom HTTP header
and not REMOTE_USER, it is not easy to test. This commit modifies
remote user tests in order to make them more generic. 
django/contrib/auth/tests/test_remote_user.py