def METHOD_NAME(self):
    self.prepare_client()
    server = self.create_server()
    auth_header = self.create_basic_auth('client', 'secret')
    request = self.factory.post(
        '/oauth/token',
        data={'grant_type': 'refresh_token'},
        HTTP_AUTHORIZATION=auth_header
    )
    resp = server.create_token_response(request)
    self.assertEqual(resp.status_code, 400)
    data = json.loads(resp.content)
    self.assertEqual(data['error'], 'invalid_request')
    self.assertIn('Missing', data['error_description'])
    request = self.factory.post(
        '/oauth/token',
        data={'grant_type': 'refresh_token', 'refresh_token': 'invalid'},
        HTTP_AUTHORIZATION=auth_header
    )
    resp = server.create_token_response(request)
    self.assertEqual(resp.status_code, 400)
    data = json.loads(resp.content)
    self.assertEqual(data['error'], 'invalid_grant')