blocks|key|699250|text|您需要设置datetime.now函数。在下面的示例中，我创建了可以在以后的其他测试中重用的夹具：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|699251|import+datetime
import+pytest

FAKE_TIME+=+datetime.datetime(2020,+12,+25,+17,+5,+55)

@pytest.fixture
def+patch_datetime_now(monkeypatch):

++++class+mydatetime:
++++++++@classmethod
++++++++def+now(cls):
++++++++++++return+FAKE_TIME

++++monkeypatch.setattr(datetime,+'datetime',+mydatetime)


def+test_patch_datetime(patch_datetime_now):
++++assert+datetime.datetime.now()+==+FAKE_TIME|code-block|syntax|javascript|699252|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You need to monkeypatch datetime.now function. In example below, I'm creating fixture which I can re-use later in other tests:

<pre><code>import datetime
import pytest

FAKE_TIME = datetime.datetime(2020, 12, 25, 17, 5, 55)

@pytest.fixture
def patch_datetime_now(monkeypatch):

 class mydatetime:
 @classmethod
 def now(cls):
 return FAKE_TIME

 monkeypatch.setattr(datetime, 'datetime', mydatetime)


def test_patch_datetime(patch_datetime_now):
 assert datetime.datetime.now() == FAKE_TIME
</code></pre>

blocks|key|698009|text|这是我用来覆盖now()但让剩下的日期时间正常工作的工具(RE:+satoru的问题)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|698010|它没有经过广泛的测试，但它确实解决了在其他上下文中使用日期时间的问题。对我来说，这对于让Django+ORM使用这些日期时间值(特别是isinstance(Freeze.now(),+datetime.datetime)+==+True)是很重要的。|offset|length|style|CODE|698011|@pytest.fixture
def+freeze(monkeypatch):
++++"""+Now()+manager+patches+datetime+return+a+fixed,+settable,+value
++++++++(freezes+time)
++++"""
++++import+datetime
++++original+=+datetime.datetime

++++class+FreezeMeta(type):
++++++++def+__instancecheck__(self,+instance):
++++++++++++if+type(instance)+==+original+or+type(instance)+==+Freeze:
++++++++++++++++return+True

++++class+Freeze(datetime.datetime):
++++++++__metaclass__+=+FreezeMeta

++++++++@classmethod
++++++++def+freeze(cls,+val):
++++++++++++cls.frozen+=+val

++++++++@classmethod
++++++++def+now(cls):
++++++++++++return+cls.frozen

++++++++@classmethod
++++++++def+delta(cls,+timedelta=None,+**kwargs):
++++++++++++"""+Moves+time+fwd/bwd+by+the+delta"""
++++++++++++from+datetime+import+timedelta+as+td
++++++++++++if+not+timedelta:
++++++++++++++++timedelta+=+td(**kwargs)
++++++++++++cls.frozen+%2B=+timedelta

++++monkeypatch.setattr(datetime,+'datetime',+Freeze)
++++Freeze.freeze(original.now())
++++return+Freeze|code-block|syntax|javascript|698012|也许不谈这个话题，但对于其他人来说，这个问题可能会派上用场。这个夹具允许“冻结”时间，然后在测试中随意地来回移动它：|698013|def+test_timesensitive(freeze):
++++freeze.freeze(2015,+1,+1)
++++foo.prepare()++#+Uses+datetime.now()+to+prepare+its+state
++++freeze.delta(days=2)
++++#+Does+something+that+takes+in+consideration+that+2+days+have+passed
++++#+i.e.+datetime.now()+returns+a+date+2+days+in+the+future
++++foo.do_something()
++++assert+foo.result+==+expected_result_after_2_days|698014|entityMap^0|0|1V|1F|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|Y|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

This is the fixture I use for overriding now() but keeping the rest of datetime working (RE: satoru's question). 

It is not extensively tested, but it does get around issues where datetime is used in other contexts. For me this was important to keep the Django ORM working with these datetime values (Specifically <code>isinstance(Freeze.now(), datetime.datetime) == True</code>).

<pre><code>@pytest.fixture
def freeze(monkeypatch):
 """ Now() manager patches datetime return a fixed, settable, value
 (freezes time)
 """
 import datetime
 original = datetime.datetime

 class FreezeMeta(type):
 def __instancecheck__(self, instance):
 if type(instance) == original or type(instance) == Freeze:
 return True

 class Freeze(datetime.datetime):
 __metaclass__ = FreezeMeta

 @classmethod
 def freeze(cls, val):
 cls.frozen = val

 @classmethod
 def now(cls):
 return cls.frozen

 @classmethod
 def delta(cls, timedelta=None, **kwargs):
 """ Moves time fwd/bwd by the delta"""
 from datetime import timedelta as td
 if not timedelta:
 timedelta = td(**kwargs)
 cls.frozen += timedelta

 monkeypatch.setattr(datetime, 'datetime', Freeze)
 Freeze.freeze(original.now())
 return Freeze
</code></pre>

Perhaps off topic, but might come in handy to other people arriving at this question. This fixture allows "freezing" time, and then moving it back and forth at will within your tests:

<pre><code>def test_timesensitive(freeze):
 freeze.freeze(2015, 1, 1)
 foo.prepare() # Uses datetime.now() to prepare its state
 freeze.delta(days=2)
 # Does something that takes in consideration that 2 days have passed
 # i.e. datetime.now() returns a date 2 days in the future
 foo.do_something()
 assert foo.result == expected_result_after_2_days
</code></pre>

blocks|key|698027|text|有模块|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|698028|from+datetime+import+datetime
from+freezegun+import+freeze_time+#+$+pip+install+freezegun

@freeze_time("Jan+14th,+2012")
def+test_nice_datetime():
++++assert+datetime.now()+==+datetime(2012,+1,+14)|code-block|syntax|javascript|698029|freeze_time()也可以用作上下文管理器。模块支持指定本地时区UTC偏移量。|style|CODE|698030|entityMap|0|LINK|mutability|MUTABLE|url|http://stevepulec.com/freezegun/^0|1|2|0|0|0|0|D|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@$A|10|B|11|K|L]]|9|@]|C|$]]|$1|M|3|-4|5|6|7|12|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

There is <a href="http://stevepulec.com/freezegun/"><code>freezegun</code> module</a>:

<pre><code>from datetime import datetime
from freezegun import freeze_time # $ pip install freezegun

@freeze_time("Jan 14th, 2012")
def test_nice_datetime():
 assert datetime.now() == datetime(2012, 1, 14)
</code></pre>

<code>freeze_time()</code> could also be used as a context manager. The module support specifying the local timezone UTC offset.

blocks|key|2238529|text|改编自其他答复：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2238530|import+datetime+as+dt
from+contextlib+import+contextmanager
from+unittest.mock+import+patch

@contextmanager
def+mocked_now(now):
++++class+MockedDatetime(dt.datetime):
++++++++@classmethod
++++++++def+now(cls):
++++++++++++return+now

++++with+patch("datetime.datetime",+MockedDatetime):
++++++++yield|code-block|syntax|javascript|2238531|用于：|2238532|def+test_now():
++++with+mocked_now(dt.datetime(2017,+10,+21)):
++++++++assert+dt.datetime.now()+==+dt.datetime(2017,+10,+21)|2238533|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Adapted from the other answers:
<pre><code>import datetime as dt
from contextlib import contextmanager
from unittest.mock import patch

@contextmanager
def mocked_now(now):
 class MockedDatetime(dt.datetime):
 @classmethod
 def now(cls):
 return now

 with patch(&quot;datetime.datetime&quot;, MockedDatetime):
 yield
</code></pre>
Used like:
<pre><code>def test_now():
 with mocked_now(dt.datetime(2017, 10, 21)):
 assert dt.datetime.now() == dt.datetime(2017, 10, 21)
</code></pre>

blocks|key|2238560|text|使用MagicMock(wrap=datetime.datetime)怎么样？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2238561|这个方法模拟datetime.datetime.now()，但其他方法与原始datetime.datetime一样可用。|2238562|from+unittest.mock+import+MagicMock

def+test_datetime_now(monkeypatch):
++++import+datetime
++++FAKE_NOW+=+datetime.datetime(2020,+3,+11,+14,+0,+0)
++++datetime_mock+=+MagicMock(wraps=datetime.datetime)
++++datetime_mock.now.return_value+=+FAKE_NOW
++++monkeypatch.setattr(datetime,+"datetime",+datetime_mock)

++++assert+datetime.datetime.now()+==+FAKE_NOW

++++#+the+other+methods+are+available
++++assert+datetime.datetime.fromisoformat("2020-03-01T00:00:00")+==+datetime.datetime(2020,+3,+1,+0,+0,+0)|code-block|syntax|javascript|2238563|这里使用的是@pytest.fixture方法。|2238564|import+datetime
from+unittest.mock+import+MagicMock

import+pytest

FAKE_NOW+=+datetime.datetime(2020,+3,+11,+14,+0,+0)


@pytest.fixture()
def+mock_datetime_now(monkeypatch):
++++datetime_mock+=+MagicMock(wraps=datetime.datetime)
++++datetime_mock.now.return_value+=+FAKE_NOW
++++monkeypatch.setattr(datetime,+"datetime",+datetime_mock)


def+test_datetime_now2(mock_datetime_now):
++++assert+datetime.datetime.now()+==+FAKE_NOW

++++assert+datetime.datetime.fromisoformat("2020-03-01T00:00:00")+==+datetime.datetime(2020,+3,+1,+0,+0,+0)|2238565|entityMap^0|2|X|0|6|N|12|H|0|0|6|F|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|R|$]]

How about using <code>MagicMock(wrap=datetime.datetime)</code> ?

This aproach mocks <code>datetime.datetime.now()</code> but the other methods are available same with the original <code>datetime.datetime</code>.

<pre><code>from unittest.mock import MagicMock

def test_datetime_now(monkeypatch):
 import datetime
 FAKE_NOW = datetime.datetime(2020, 3, 11, 14, 0, 0)
 datetime_mock = MagicMock(wraps=datetime.datetime)
 datetime_mock.now.return_value = FAKE_NOW
 monkeypatch.setattr(datetime, "datetime", datetime_mock)

 assert datetime.datetime.now() == FAKE_NOW

 # the other methods are available
 assert datetime.datetime.fromisoformat("2020-03-01T00:00:00") == datetime.datetime(2020, 3, 1, 0, 0, 0)

</code></pre>

Using <code>@pytest.fixture</code> approach is here.

<pre><code>import datetime
from unittest.mock import MagicMock

import pytest

FAKE_NOW = datetime.datetime(2020, 3, 11, 14, 0, 0)


@pytest.fixture()
def mock_datetime_now(monkeypatch):
 datetime_mock = MagicMock(wraps=datetime.datetime)
 datetime_mock.now.return_value = FAKE_NOW
 monkeypatch.setattr(datetime, "datetime", datetime_mock)


def test_datetime_now2(mock_datetime_now):
 assert datetime.datetime.now() == FAKE_NOW

 assert datetime.datetime.fromisoformat("2020-03-01T00:00:00") == datetime.datetime(2020, 3, 1, 0, 0, 0)

</code></pre>

blocks|key|698066|text|如果您是pytest-mock的爱好者，那么使用下面的代码来模拟datetime.now。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|698067|from+datetime+import+datetime,+timezone

def+test_time_now(mocker):
++++#patch+the+the+datetime+method+in+your+file

++++mock_date+=+mocker.patch("your_package.your_package.datetime")
++++FAKE_NOW+=+datetime(2020,+3,+11,+14,+0,+0,+tzinfo=timezone.utc)
++++mock_date.now.return_value+=+FAKE_NOW
++++
++++from+your_package.your_package+import+time_to_test
++++timestamp_method+=+time_to_test()
++++assert+timestamp_method+==+FAKE_NOW|code-block|syntax|javascript|698068|entityMap^0|W|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

If you are a lover of pytest-mock, then mock the <code>datetime.now</code> using this.
<pre><code>from datetime import datetime, timezone

def test_time_now(mocker):
 #patch the the datetime method in your file

 mock_date = mocker.patch(&quot;your_package.your_package.datetime&quot;)
 FAKE_NOW = datetime(2020, 3, 11, 14, 0, 0, tzinfo=timezone.utc)
 mock_date.now.return_value = FAKE_NOW
 
 from your_package.your_package import time_to_test
 timestamp_method = time_to_test()
 assert timestamp_method == FAKE_NOW
</code></pre>

blocks|key|699371|text|轻松地使用unittest.mock.patch作为上下文管理器，wright在测试中：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|699372|import+datetime
import+pytest
from+unittest.mock+import+patch


def+test_schedule(schedules_db_client):

++++faked_now+=+datetime.datetime(2022,+1,+1,+14,+0,+0)

++++with+patch("datetime.datetime")+as+mock_datetime:
++++++++mock_datetime.now.return_value+=+faked_now

++++++++assert+schedules_db_client.get_current_attendant()|code-block|syntax|javascript|699373|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.python.org/3/library/unittest.mock.html#unittest.mock.patch^0|5|J|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

it handly to use <a href="https://docs.python.org/3/library/unittest.mock.html#unittest.mock.patch" rel="nofollow noreferrer">unittest.mock.patch</a> as context manager, wright in test:
<pre><code>import datetime
import pytest
from unittest.mock import patch


def test_schedule(schedules_db_client):

 faked_now = datetime.datetime(2022, 1, 1, 14, 0, 0)

 with patch(&quot;datetime.datetime&quot;) as mock_datetime:
 mock_datetime.now.return_value = faked_now

 assert schedules_db_client.get_current_attendant()
</code></pre>

blocks|key|698096|text|还有一个菜谱，使用pytest-mock和显式MagicMock来包装now方法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|698097|from+datetime+import+datetime

from+my_module+import+fn_returning_datetime_now

def+test_datetime(mocker):
++++NOW+=+dt.datetime(1999,1,1)
++++mock_datetime+=+mocker.MagicMock(wraps=datetime)
++++mock_datetime.now.return_value+=+NOW
++++mocker.patch("my_module.datetime",+mock_datetime)
++++assert+fn_returning_datetime_now+==+NOW|code-block|syntax|javascript|698098|这只是这里的其他答案的一个变化，使用mocker.patch而不是monkeypatch。|698099|entityMap^0|9|B|N|9|Z|3|0|0|I|C|X|B|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

Yet another recipe, using <code>pytest-mock</code> with an explicit <code>MagicMock</code> to wrap only the <code>now</code> method:
<pre class="lang-py prettyprint-override"><code>from datetime import datetime

from my_module import fn_returning_datetime_now

def test_datetime(mocker):
 NOW = dt.datetime(1999,1,1)
 mock_datetime = mocker.MagicMock(wraps=datetime)
 mock_datetime.now.return_value = NOW
 mocker.patch(&quot;my_module.datetime&quot;, mock_datetime)
 assert fn_returning_datetime_now == NOW
</code></pre>
This is just a variation on other answers here, using <code>mocker.patch</code> instead of <code>monkeypatch</code>.

I need to test functions which uses <code>datetime.datetime.now()</code>. What is the easiest way to do this?

How to monkeypatch python's datetime.datetime.now with py.test?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我需要测试使用datetime.datetime.now()的函数。做这件事最简单的方法是什么？

问如何用datetime.datetime.now对蟒蛇的py.test进行猴子识别？
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问如何用datetime.datetime.now对蟒蛇的py.test进行猴子识别？EN