def test_create_user_is_successful(self):
    response = create_user()
    self.assertEqual(200, response.status_code, 'Response should be 200 OK')
    self.assertEqual('application/json', response.headers['Content-Type'], 'Content-Type should be application/json')
    data = response.json()
    self.assertIn('identifier', data, 'Data should have identifier key')
    self.assertTrue(is_uuid4(data['identifier']), 'identifier should be a valid uuid')
def test_create_user_is_successful(self):
    response = create_user()
    self.assertEqual(200, response.status_code, 'Response should be 200 OK')
    self.assertEqual('application/json', response.headers['Content-Type'], 'Content-Type should be application/json')
    data = response.json()
    self.assertIn('identifier', data, 'Data should have identifier key')
    self.assertTrue(is_uuid4(data['identifier']), 'identifier should be a valid uuid')