不能monkeypatch导入的模块

Question

I have a very simple Google Cloud Function written in Python and it makes a reference to Google's Secret manager via their Python library.

The code is very simple and it looks like this:

import os
from google.cloud import secretmanager
import logging

client = secretmanager.SecretManagerServiceClient()
secret_name = "my-secret"
project_id = os.environ.get('GCP_PROJECT')
resource_name = "projects/{}/secrets/{}/versions/latest".format(project_id, secret_name)
response = client.access_secret_version(resource_name)
secret_string = response.payload.data.decode('UTF-8')

def new_measures_handler(data, context):
    logging.info(secret_string)
    print('File: {}.'.format(data['name']))

and then I have my simple unit test which is trying to take advantage of monkey patching :

import main

def test_print(capsys, monkeypatch):
    # arrange
    monkeypatch.setenv("GCP_PROJECT", "TestingUser")
    monkeypatch.setattr(secretmanager, "SecretManagerServiceClient", lambda: 1)

    name = 'test'
    data = {'name': name}

    # act
    main.new_measures_handler(data, None)
    out, err = capsys.readouterr()

    #assert
    assert out == 'File: {}.\n'.format(name)

Everything goes well with the mock for the environment variable but I can not mock secretmanager . It keeps on trying to call the actual API. My ultimate goal is to mock secretmanager.SecretManagerServiceClient() and make it return an object which later on can be used by: client.access_secret_version(resource_name) (which I will need to mock as well, I think)

Answer 1

有关使用unittest修补和模拟来模拟 Google API 调用并返回模拟结果的工作示例，请参阅我对此问题的回答： How to Mock a Google API Library with Python 3.7 for Unit Testing