Pytest：集合错误，函数不使用参数“日期”

Question

为什么 Pytest 返回集合错误“在 test_billing_month_year：函数不使用参数“日期”，即使使用并定义了日期？

billing_month_year() 函数仅返回当前日期的上个月和上一年。

import datetime as dt
import pytest 
from mock import patch

def billing_month_year():
    today = dt.datetime.utcnow()
    #last month from current date
    last_month = today.month - 1 if today.month>1 else 12
    #last year from current date
    last_month_year = today.year if today.month > last_month else today.year - 1
    return last_month, last_month_year

@pytest.mark.parametrize(
    'date, expected',
    [
        #last month in previous year
        (dt.datetime(year=2020, month=1, day=21), (12, 2019)),
        #last month in current year
        (dt.datetime(year=2020, month=2, day=21), (01, 2020)),
    ]
)
@patch('dt.datetime.utcnow')
def test_billing_month_year(date, expected, mock_utcnow):
    mock_utcnow.return_value = date
    test = billing_month_year()
    assert test == expected

Answer 1

装饰器总是以与添加它们相反的顺序应用，例如，在这种情况下，首先应用patch装饰器，然后pytest.mark.parametrize应用装饰器。这意味着参数应按各自的顺序排列：

@pytest.mark.parametrize(
    'date, expected',
    [
        (dt.datetime(year=2020, month=1, day=21), (12, 2019)),
        (dt.datetime(year=2020, month=2, day=21), (01, 2020)),
    ]
)
@patch('dt.datetime.utcnow')
def test_billing_month_year(mock_utcnow, date, expected):
    mock_utcnow.return_value = date
    test = billing_month_year()
    assert test == expected

修补程序可能也不起作用，请参阅此问题的答案以获取解决方案。