如何为带重试与超时的Python requests请求函数编写单元测试

原函数代码（修正语法错误后） #

from requests import Session
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

def http_request(method, url):
    session = Session()
    retries = Retry(total=3, backoff_factor=0.5, status_forcelist=list(range(500, 600)))
    for prefix in ('http://', 'https://'):
        session.mount(prefix, HTTPAdapter(max_retries=retries))
    response = session.request(method, url, timeout=(31,123))
    response.raise_for_status()
    return response

测试需求验证方案 #

1. 验证500-600状态码触发3次重试（总计4次调用） #

使用requests-mock模拟服务器返回500错误，通过统计mock的调用次数确认重试逻辑生效。

测试代码（基于pytest）：

import pytest
import requests_mock
from your_module import http_request  # 替换为实际的模块名

def test_http_request_retries_on_server_errors():
    with requests_mock.Mocker() as m:
        # 模拟目标URL返回500状态码
        m.register_uri('GET', 'http://example.com', status_code=500)
        
        with pytest.raises(requests.exceptions.HTTPError):
            # 调用目标函数，预期最终重试失败后抛出HTTPError
            http_request('GET', 'http://example.com')
        
        # 验证总调用次数为4次（1次初始请求 + 3次重试）
        assert m.call_count == 4

2. 验证超时设置被正确传递 #

通过unittest.mock补丁requests.Session.request方法，检查调用时是否传入了正确的超时参数。

测试代码（基于pytest）：

from unittest.mock import patch, MagicMock
from your_module import http_request  # 替换为实际的模块名

def test_http_request_timeout_setting():
    with patch('requests.Session.request') as mock_request:
        # 模拟响应成功，避免抛出异常
        mock_response = MagicMock()
        mock_response.raise_for_status.return_value = None
        mock_request.return_value = mock_response
        
        # 调用目标函数
        http_request('GET', 'http://example.com')
        
        # 验证request方法被调用时，timeout参数正确设置为(31, 123)
        mock_request.assert_called_once_with(
            'GET',
            'http://example.com',
            timeout=(31, 123)
        )

依赖说明 #

运行测试前需要安装依赖：

pip install pytest requests-mock

内容的提问来源于stack exchange，提问作者iAmoric