谁能告诉我为什么这行不通?
>>> import mock
>>> @mock.patch('datetime.date.today')
... def today(cls):
... return date(2010, 1, 1)
...
>>> from datetime import date
>>> date.today()
datetime.date(2010, 12, 19)
也许有人能提出一个更好的办法?
谁能告诉我为什么这行不通?
>>> import mock
>>> @mock.patch('datetime.date.today')
... def today(cls):
... return date(2010, 1, 1)
...
>>> from datetime import date
>>> date.today()
datetime.date(2010, 12, 19)
也许有人能提出一个更好的办法?
当前回答
http://blog.xelnor.net/python-mocking-datetime/中讨论了几种解决方案。总而言之:
模拟对象-简单有效,但打破isinstance()检查:
target = datetime.datetime(2009, 1, 1)
with mock.patch.object(datetime, 'datetime', mock.Mock(wraps=datetime.datetime)) as patched:
patched.now.return_value = target
print(datetime.datetime.now())
模拟类
import datetime
import mock
real_datetime_class = datetime.datetime
def mock_datetime_now(target, dt):
class DatetimeSubclassMeta(type):
@classmethod
def __instancecheck__(mcs, obj):
return isinstance(obj, real_datetime_class)
class BaseMockedDatetime(real_datetime_class):
@classmethod
def now(cls, tz=None):
return target.replace(tzinfo=tz)
@classmethod
def utcnow(cls):
return target
# Python2 & Python3 compatible metaclass
MockedDatetime = DatetimeSubclassMeta('datetime', (BaseMockedDatetime,), {})
return mock.patch.object(dt, 'datetime', MockedDatetime)
使用:
with mock_datetime_now(target, datetime):
....
其他回答
我使用自定义装饰器实现了@user3016183方法:
def changeNow(func, newNow = datetime(2015, 11, 23, 12, 00, 00)):
"""decorator used to change datetime.datetime.now() in the tested function."""
def retfunc(self):
with mock.patch('mymodule.datetime') as mock_date:
mock_date.now.return_value = newNow
mock_date.side_effect = lambda *args, **kw: datetime(*args, **kw)
func(self)
return retfunc
我想这也许有一天能帮到别人…
你可以用这个来模拟datetime:
在sources.py模块中:
import datetime
class ShowTime:
def current_date():
return datetime.date.today().strftime('%Y-%m-%d')
在您的tests.py中:
from unittest import TestCase, mock
import datetime
class TestShowTime(TestCase):
def setUp(self) -> None:
self.st = sources.ShowTime()
super().setUp()
@mock.patch('sources.datetime.date')
def test_current_date(self, date_mock):
date_mock.today.return_value = datetime.datetime(year=2019, month=10, day=1)
current_date = self.st.current_date()
self.assertEqual(current_date, '2019-10-01')
对我来说最简单的方法是:
import datetime
from unittest.mock import Mock, patch
def test():
datetime_mock = Mock(wraps=datetime.datetime)
datetime_mock.now.return_value = datetime.datetime(1999, 1, 1)
with patch('datetime.datetime', new=datetime_mock):
assert datetime.datetime.now() == datetime.datetime(1999, 1, 1)
注意:target_module中的datetime模块中的所有功能都将停止工作。
也许您可以使用自己的“today()”方法,在需要的地方打补丁。使用utcnow()的示例可以在这里找到:https://bitbucket.org/k_bx/blog/src/tip/source/en_posts/2012-07-13-double-call-hack.rst?at=default
您可以使用以下基于Daniel G解的方法。这个方法的优点是不会破坏isinstance(d, datetime.date)的类型检查。
import mock
def fixed_today(today):
from datetime import date
class FakeDateType(type):
def __instancecheck__(self, instance):
return isinstance(instance, date)
class FakeDate(date):
__metaclass__ = FakeDateType
def __new__(cls, *args, **kwargs):
return date.__new__(date, *args, **kwargs)
@staticmethod
def today():
return today
return mock.patch("datetime.date", FakeDate)
基本上,我们取代了基于c语言的datetime。Date类,使用我们自己的python子类,生成原始的datetime。日期实例,并响应isinstance()查询完全与本机datetime.date相同。
在测试中使用它作为上下文管理器:
with fixed_today(datetime.date(2013, 11, 22)):
# run the code under test
# note, that these type checks will not break when patch is active:
assert isinstance(datetime.date.today(), datetime.date)
类似的方法可用于模拟datetime.datetime.now()函数。