Question

我正在使用unittest框架为python程序编写单元测试。该程序的一个功能是使用请求库连接到外部REST API。如果出现连接错误或超时，我希望该功能在失败前重试最多3次。因此我编写了一个测试，它使用mock（实际上是httpretty）来替换外部API并在返回之前引发两次requests.ConnectionError。

class APITests(unittest.TestCase):

    def mock_response(self, uri, body='OK', method=httpretty.GET,
                      status_code=200, error=None,
                      error_repeats=None):
        """
        Function to register HTTPretty response
        """
        responses = []

        if error:
            def callback(request, uri, headers):
                raise error

            if error_repeats:
                responses += [httpretty.Response(body=callback)]*error_repeats
                responses += [httpretty.Response(body=body,
                                                 status=status_code)]
            else:
                responses += [httpretty.Response(body=callback)]

        else:
            responses += [httpretty.Response(body=body, status=status_code)]

        httpretty.register_uri(method, uri, responses=responses)

    @httpretty.activate
    def test_get_connection_error_then_success_doesnt_raise(self):
        self.mock_response(
                'http://irrelevant.com',
                error=requests.ConnectionError,
                error_repeats=2
            )
        api._get('http://irrelevant.com')

这样可以正常运行，当没有引发异常而没有第三次尝试时，测试通过，但是由代码引发（故意）和捕获并处理的两个异常被打印到控制台，污染了测试输出。是否有一种干净的方法来阻止这种情况发生？

更多信息

以下是我正在测试的方法

def _get(self, url, retries=3):
    while retries > 0:
        try:
            r = requests.get(url)
            try:
                r.raise_for_status()
                return r
            except requests.HTTPError as e:
                self._handle_HTTP_error(e)
        except (requests.ConnectionError, requests.Timeout) as e:
            retries -= 1
            if not retries:
                self._handle_connection_error(e)

def _handle_connection_error(self, error):
    raise requests.ConnectionError('Could not connect to API')

控制台输出是：

Exception in thread Thread-23:
Traceback (most recent call last):
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 810, in __bootstrap_inner
    self.run()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 763, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/Users/lukecaldwell/Documents/Repos/other/AidTrends/venv/lib/python2.7/site-packages/httpretty/core.py", line 637, in fill_filekind
    headers
  File "/Users/lukecaldwell/Documents/Repos/other/AidTrends/aidtrends/tests/test_OECD.py", line 131, in callback
    raise error
ConnectionError

沉默异常不会导致python unittest中的测试失败

0 个答案: