Python:模拟日期时间问题

Question

这是我的 Python 方法:

for time in (timedelta(hours=3), timedelta(minutes=30)):

    delay = (datetime.now() + time).strftime('%Y-%m-%dT%H:%M:%S')
    payload = json.dumps({
        "channels": [
            "accountID-{acct_id}".format(acct_id=account_id)
        ],
        "push_time": delay,
        "data": {
            "alert": "Test Push",
            "m": "12345"
        },
    })

    try:
        requests.post(
            "https://api.parse.com/1/push",
            data=payload,
            headers={
                "X-Parse-Application-Id": settings.PARSE_APPLICATION_ID,
                "X-Parse-REST-API-Key": settings.PARSE_REST_API_KEY,
                "Content-Type": "application/json"
            }
        )
    except requests.exceptions.RequestException as e:
        logging.getLogger().setLevel(logging.ERROR)

这是我的测试:

@patch("requests.post")
def test_send_push_notifications_to_parse(self, post_mock):
    post_mock.return_value = {"status": 200}
    mailing = Mock()
    mailing.name = "Foo Name"
    mailing.account_id = 12345
    mailing.mailing_id = 45

    payload = json.dumps({
        "channels": [
            "accountID-12345"
        ],
        "push_time": "2014-03-04T15:00:00",
        "data": {
            "alert": "Test Push",
            "m": "12345"
        },
    })

    send_push_notification_to_parse(mailing.account_id, mailing.mailing_id, mailing.name)

    post_mock.assert_called_with(
        "https://api.parse.com/1/push",
        data=payload,
        headers={
            "X-Parse-Application-Id": settings.PARSE_APPLICATION_ID,
            "X-Parse-REST-API-Key": settings.PARSE_REST_API_KEY,
            "Content-Type": "application/json"
        }
    )

测试失败，因为 POST 请求位于 datetime 对象发生更改的循环内。如何修补 datetime 对象以使我的测试通过？

Answer 1

只需在模块中模拟日期时间:

@patch("your.module.datetime")
@patch("requests.post")
def test_send_push_notifications_to_parse(self, post_mock, dt_mock):
    # set datetime.now() to a fixed value
    dt_mock.now.return_value = datetime.datetime(2013, 2, 1, 10, 9, 8)

您通过导入将datetime绑定(bind)到模块中，上面的@patch装饰器将用模拟替换该对象。

如果需要测试多个值，可以设置 dt_mock.now.side_effect attribute反而;列表将导致模拟在顺序调用时从该列表中一一返回值，一种方法可让您在每次根据需要调用 datetime.now() 时生成一个新值。