pytest测试Slack API时无法返回自定义错误原因的解决问询

问题背景 #

我用Python的Slack SDK编写pytest测试脚本，用于验证Slack API请求的有效性，希望测试失败时返回Slack WebClient提供的具体失败原因。但故意使用错误API token测试时，仅收到通用的请求失败提示，而非包含具体原因的自定义信息。

现有代码 #

import sys
import time 
import pytest
from slack_sdk import WebClient, errors
import ssl

slack_token = 'xoxb-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'
channel_id = "C00000000"
ssl_context = ssl.create_default_context()
ssl_context.check_hostname = False
ssl_context.verify_mode = ssl.CERT_NONE
client = WebClient(token=slack_token, ssl=ssl_context)


def test_api_call(status=True):

    """
        Test which checks whether or not the API 
        call to conversations_history returns and 'ok' 
        status. If it fails, the error message will be 
        returned.
    """

    result = client.conversations_history(
        channel     = channel_id,
        inclusive   = True,
        oldest      = str(time.time()-3600),
        latest      = str(time.time()),
        limit       = 100
    )
    assert result["ok"] == status, \
        f"Expected {status}. Actual status {result['ok']}. Response text {result['error']}" 

当前错误输出 #

test_alerts.py:25: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
../../.local/share/virtualenvs/new_project-RFzzfWjC/lib/python3.10/site-packages/slack_sdk/web/client.py:2488: in conversations_history
    return self.api_call("conversations.history", http_verb="GET", params=kwargs)
../../.local/share/virtualenvs/new_project-RFzzfWjC/lib/python3.10/site-packages/slack_sdk/web/base_client.py:156: in api_call
    return self._sync_send(api_url=api_url, req_args=req_args)
../../.local/share/virtualenvs/new_project-RFzzfWjC/lib/python3.10/site-packages/slack_sdk/web/base_client.py:187: in _sync_send
    return self._urllib_api_call(
../../.local/share/virtualenvs/new_project-RFzzfWjC/lib/python3.10/site-packages/slack_sdk/web/base_client.py:317: in _urllib_api_call
    ).validate()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <slack_sdk.web.slack_response.SlackResponse object at 0x101a8d1b0>

    def validate(self):
        """Check if the response from Slack was successful.
    
        Returns:
            (SlackResponse)
                This method returns it's own object. e.g. 'self'
    
        Raises:
            SlackApiError: The request to the Slack API failed.
        """
        if self.status_code == 200 and self.data and (isinstance(self.data, bytes) or self.data.get("ok", False)):
            return self
        msg = f"The request to the Slack API failed. (url: {self.api_url})"
>       raise e.SlackApiError(message=msg, response=self)
E       slack_sdk.errors.SlackApiError: The request to the Slack API failed. (url: https://www.slack.com/api/conversations.history)
E       The server responded with: {'ok': False, 'error': 'invalid_auth'}

../../.local/share/virtualenvs/new_project-RFzzfWjC/lib/python3.10/site-packages/slack_sdk/web/slack_response.py:199: SlackApiError
====================================================================== short test summary info ======================================================================
FAILED test_alerts.py::test_api_call - slack_sdk.errors.SlackApiError: The request to the Slack API failed. (url: https://www.slack.com/api/conversations.history)
========================================================================= 1 failed in 1.04s ========================================================================= 

期望输出 #

FAILED test_alerts.py::test_api_call - slack_sdk.errors.SlackApiError: Expected True. Actual status False. Response text invalid_auth
========================================================================= 1 failed in 1.04s ========================================================================= 

Slack API官方错误响应示例 #

{
  "ok": false, 
  "error": "invalid_auth"
}

解决方案 #

问题出在Slack SDK的默认行为：当API返回ok: false时，WebClient会自动抛出SlackApiError异常，你的断言代码根本没机会执行。要获取自定义错误信息，需要捕获这个异常并从中提取具体错误数据。

修改后的代码如下：

import sys
import time 
import pytest
from slack_sdk import WebClient, errors
import ssl

slack_token = 'xoxb-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'
channel_id = "C00000000"
ssl_context = ssl.create_default_context()
ssl_context.check_hostname = False
ssl_context.verify_mode = ssl.CERT_NONE
client = WebClient(token=slack_token, ssl=ssl_context)


def test_api_call(status=True):
    """测试conversations_history API调用是否返回'ok'状态，失败时返回具体错误原因"""
    try:
        result = client.conversations_history(
            channel     = channel_id,
            inclusive   = True,
            oldest      = str(time.time()-3600),
            latest      = str(time.time()),
            limit       = 100
        )
        assert result["ok"] == status, \
            f"Expected {status}. Actual status {result['ok']}. Response text {result['error']}"
    except errors.SlackApiError as e:
        # 从异常响应中提取Slack返回的具体错误信息
        response_data = e.response.data
        assert response_data["ok"] == status, \
            f"Expected {status}. Actual status {response_data['ok']}. Response text {response_data['error']}"

修改说明 #

• 添加try-except块捕获SlackApiError异常，确保API失败时不会直接终止测试
• 从异常对象的e.response.data中获取完整的Slack响应数据，包含ok和error字段
• 在异常处理块中执行相同的断言逻辑，构造自定义的错误提示信息

这样测试失败时，pytest就会输出你期望的包含具体错误原因的提示。

内容的提问来源于stack exchange，提问作者Keith Cozart