如何模拟一个方法，使多个 POST 和 GET 请求都需要不同的响应数据？

Question

我已经查看了如何模拟 REST API并阅读了答案，但我似乎仍然无法理解如何处理执行多个 GET 和 POST 请求的方法。下面是我的一些代码。

我有课，UserAliasGroups(). __init__()执行其方法requests.post()以登录外部 REST API。我在单元测试中使用此代码来处理登录的模拟，并且它按预期工作。

    @mock.patch('aliases.user_alias_groups.requests.get')
    @mock.patch('aliases.user_alias_groups.requests.post')
    def test_user_alias_groups_class(self, mock_post, mock_get):
        init_response = {
            'HID-SessionData': 'token==',
            'errmsg': '',
            'success': True
        }
        mock_response = Mock()
        mock_response.json.return_value = init_response
        mock_response.status_code = status.HTTP_201_CREATED
        mock_post.return_value = mock_response

        uag = UserAliasGroups(auth_user='TEST_USER.gen',
                              auth_pass='FakePass',
                              groups_api_url='https://example.com')
        self.assertEqual(uag.headers, {'HID-SessionData': 'token=='})

我还定义了几种方法，如obtain_request_id()、has_group_been_deleted()、does_group_already_exists()等。我还定义了一个名为的方法，create_user_alias_group()该方法调用obtain_request_id()、has_group_been_deleted()和does_group_already_exists()其他方法。

我的单元测试中还有代码来模拟对 REST API 的 GET 请求，以测试我的has_group_been_deleted()方法，如下所示：

        has_group_been_deleted_response = {
            'error_code': 404, 
            'error_message': 'A group with this ID does not exist'
        }
        mock_response = Mock()
        mock_response.json.return_value = has_group_been_deleted_response
        mock_response.status_code = status.HTTP_404_NOT_FOUND
        mock_get.return_value = mock_response

现在我可以回答我的问题了。以下是我的代码的相关部分。

class UserAliasGroups:

    def __init__(
            self,
            auth_user=settings.GENERIC_USER,
            auth_pass=settings.GENERIC_PASS,
            groups_api_url=settings.GROUPS_API_URL
    ):
        """ __init__() does the login to groups. """
        self.auth_user = auth_user
        self.auth_pass = auth_pass
        self.headers = None
        self.groups_api_url = groups_api_url
        # Initializes a session with the REST API service. Each login session times out after 5 minutes of inactivity.
        self.login_url = f'{self.groups_api_url}/api/login'

        response = requests.post(self.login_url, json={}, headers={'Content-type': 'application/json'},
                                 auth=(auth_user, auth_pass))
        if response.status_code is not 201:
            try:
                json = response.json()
            except:
                json = "Could not decode json."
            raise self.UserAliasGroupsException(f"Error: User {self.auth_user}, failed to login into "
                                                f"{self.login_url} {json}")

        response_json = response.json()
        self.headers = {'HID-SessionData': response_json['HID-SessionData']}

    def obtain_request_id(self, request_reason):
        payload = {'request_reason': request_reason}
        url = f'{self.groups_api_url}/api/v1/session/requests'
        response = requests.post(url=url, json=payload, headers=self.headers)
        if response.status_code is not status.HTTP_200_OK:
            try:
                json = response.json()
            except:
                json = "Could not decode json."
            msg = f'obtain_request_id() Error url={url} {response.status_code} {json}.'
            raise self.UserAliasGroupsException(msg)
        request_id = response.json().get('request_id')
        return request_id

    def has_group_been_deleted(self, group_name):
        url = f'{self.groups_api_url}/api/v1/groups/{group_name}/attributes/RESATTR_GROUP_DELETED_ON'
        response = requests.get(url=url, headers=self.headers)
        return response.status_code == status.HTTP_200_OK


    def does_group_already_exists(self, group_name):
        url = f'{self.groups_api_url}/api/v1/groups/{group_name}'
        response = requests.get(url=url, headers=self.headers)
        if response.status_code is status.HTTP_200_OK:
            # check if the group has been "deleted".
            return not self.has_group_been_deleted(group_name=group_name)
        return False

    def create_user_alias_group(
            self,
            ... long list of params omitted for brevity ...     
    ):

       if check_exists:
            # Check if group already exists or not.
            if self.does_group_already_exists(group_name):
                msg = f'Cannot create group {group_name}. Group already exists.'
                raise self.UserAliasGroupsException(msg)
       ... more code omitted for brevity ...

我的问题是如何编写单元测试来处理对我的方法的多次调用requests.post()以及request.get()所有调用都会导致不同的响应create_user_alias_group()？

我想调用create_user_alias_group()我的单元测试，所以我必须弄清楚如何模拟多个requests.get()并requests.post()调用。

我是否使用了多个这样的装饰器：

@mock.patch('aliases.user_alias_groups.obtain_request_id.requests.post')
@mock.patch('aliases.user_alias_groups.does_group_already_exists.requests.get')
@mock.patch('aliases.user_alias_groups.has_group_been_deleted.requests.get')
def test_user_alias_groups_class(self, mock_post, mock_get):
    ...

？

感谢您查看我的长问题:)

Answer 1

您可以使用mock.side_effectwhich 需要一个可迭代对象。那么不同的调用会返回不同的值：

mock = Mock()
mock.side_effect = ['a', 'b', 'c']

这样，对模拟的第一次调用将返回"a"，然后是下一个"b"，依此类推。（根据您的情况，您将设置mock_get.side_effect）。