blocks|key|1059763|text|添加到Daniel+G's+solution的步骤|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1059764|from+datetime+import+date

class+FakeDate(date):
++++"A+manipulable+date+replacement"
++++def+__new__(cls,+*args,+**kwargs):
++++++++return+date.__new__(date,+*args,+**kwargs)|code-block|syntax|javascript|1059765|这将创建一个类，该类在实例化时将返回一个普通的datetime.date对象，但该对象也可以更改。|1059766|@mock.patch('datetime.date',+FakeDate)
def+test():
++++from+datetime+import+date
++++FakeDate.today+=+classmethod(lambda+cls:+date(2010,+1,+1))
++++return+date.today()

test()+#+datetime.date(2010,+1,+1)|1059767|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/4482067/248616^0|3|J|0|0|0|0|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]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

To add to <a href="https://stackoverflow.com/a/4482067/248616">Daniel G's solution</a>:

<pre><code>from datetime import date

class FakeDate(date):
 "A manipulable date replacement"
 def __new__(cls, *args, **kwargs):
 return date.__new__(date, *args, **kwargs)
</code></pre>

This creates a class which, when instantiated, will return a normal datetime.date object, but which is also able to be changed.

<pre><code>@mock.patch('datetime.date', FakeDate)
def test():
 from datetime import date
 FakeDate.today = classmethod(lambda cls: date(2010, 1, 1))
 return date.today()

test() # datetime.date(2010, 1, 1)
</code></pre>

blocks|key|1059813|text|也许你可以使用你自己的“you+()”方法，你可以在需要的地方打补丁。可以在这里找到模拟utcnow()的示例：https://bitbucket.org/k_bx/blog/src/tip/source/en_posts/2012-07-13-double-call-hack.rst?at=default|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1059814|entityMap|0|LINK|mutability|MUTABLE|url|https://bitbucket.org/k_bx/blog/src/tip/source/en_posts/2012-07-13-double-call-hack.rst?at=default^0|1K|2Q|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Maybe you could use your own "today()" method that you will patch where needed. Example with mocking utcnow() can be found here: <a href="https://bitbucket.org/k_bx/blog/src/tip/source/en_posts/2012-07-13-double-call-hack.rst?at=default" rel="nofollow">https://bitbucket.org/k_bx/blog/src/tip/source/en_posts/2012-07-13-double-call-hack.rst?at=default</a>

blocks|key|1059894|text|我想我来得有点晚了，但我认为这里的主要问题是您直接为datetime.date.today打补丁，根据文档，这是错误的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1059895|例如，您应该修补在被测试函数所在的文件中导入的引用。|1059896|假设您有一个functions.py文件，其中包含以下内容：|1059897|import+datetime

def+get_today():
++++return+datetime.date.today()|code-block|syntax|javascript|1059898|然后，在您的测试中，您应该有如下内容|1059899|import+datetime
import+unittest

from+functions+import+get_today
from+mock+import+patch,+Mock

class+GetTodayTest(unittest.TestCase):

++++@patch('functions.datetime')
++++def+test_get_today(self,+datetime_mock):
++++++++datetime_mock.date.today+=+Mock(return_value=datetime.strptime('Jun+1+2005',+'%25b+%25d+%25Y'))
++++++++value+=+get_today()
++++++++#+then+assert+your+thing...|1059900|希望这会有一点帮助。|1059901|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|U|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|X|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I guess I came a little late for this but I think the main problem here is that you're patching datetime.date.today directly and, according to the documentation, this is wrong.

You should patch the reference imported in the file where the tested function is, for example.

Let's say you have a functions.py file where you have the following:

<pre><code>import datetime

def get_today():
 return datetime.date.today()
</code></pre>

then, in your test, you should have something like this

<pre><code>import datetime
import unittest

from functions import get_today
from mock import patch, Mock

class GetTodayTest(unittest.TestCase):

 @patch('functions.datetime')
 def test_get_today(self, datetime_mock):
 datetime_mock.date.today = Mock(return_value=datetime.strptime('Jun 1 2005', '%b %d %Y'))
 value = get_today()
 # then assert your thing...
</code></pre>

Hope this helps a little bit.

blocks|key|1059967|text|您可以使用以下方法，基于Daniel+G解决方案。这种方法的优点是不会破坏isinstance(d,+datetime.date)的类型检查。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1059968|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)|code-block|syntax|javascript|1059969|基本上，我们将基于C的datetime.date类替换为我们自己的Python子类，它生成原始的datetime.date实例，并以原生isinstance()的方式响应datetime.date查询。|1059970|在您的测试中使用它作为上下文管理器：|1059971|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)|1059972|可以使用类似的方法模拟datetime.datetime.now()函数。|1059973|entityMap^0|11|S|0|0|B|D|1C|D|1W|C|2D|D|0|0|0|B|N|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|17|8|@]|D|@]|E|$]]|$1|O|3|P|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|Q|3|R|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1C|8|@]|D|@]|E|$]]]|T|$]]

You can use the following approach, based on Daniel G solution. This one has advantage of not breaking type checking with <code>isinstance(d, datetime.date)</code>.

<pre class="lang-py prettyprint-override"><code>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)
</code></pre>

Basically, we replace C-based <code>datetime.date</code> class with our own python subclass, that produces original <code>datetime.date</code> instances and responds to <code>isinstance()</code> queries exactly as native <code>datetime.date</code>. 

Use it as context manager in your tests:

<pre class="lang-py prettyprint-override"><code>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)
</code></pre>

Similar approach can be used to mock <code>datetime.datetime.now()</code> function.

blocks|key|1060017|text|无论如何，模拟文档专门讨论了datetime.date.today，并且可以在不创建虚拟类的情况下实现这一点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1060018|https://docs.python.org/3/library/unittest.mock-examples.html#partial-mocking|offset|length|1060019|>>>+from+datetime+import+date
>>>+with+patch('mymodule.date')+as+mock_date:
...+++++mock_date.today.return_value+=+date(2010,+10,+8)
...+++++mock_date.side_effect+=+lambda+*args,+**kw:+date(*args,+**kw)
...
...+++++assert+mymodule.date.today()+==+date(2010,+10,+8)
...+++++assert+mymodule.date(2009,+6,+8)+==+date(2009,+6,+8)
...|code-block|syntax|javascript|1060020|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|25|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|H|7|W|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|C]]]]

For what it's worth, the Mock docs talk about datetime.date.today specifically, and it's possible to do this without having to create a dummy class:

<a href="https://docs.python.org/3/library/unittest.mock-examples.html#partial-mocking" rel="noreferrer">https://docs.python.org/3/library/unittest.mock-examples.html#partial-mocking</a>

<pre><code>&gt;&gt;&gt; from datetime import date
&gt;&gt;&gt; with patch('mymodule.date') as mock_date:
... mock_date.today.return_value = date(2010, 10, 8)
... mock_date.side_effect = lambda *args, **kw: date(*args, **kw)
...
... assert mymodule.date.today() == date(2010, 10, 8)
... assert mymodule.date(2009, 6, 8) == date(2009, 6, 8)
...
</code></pre>

blocks|key|845598|text|我使用自定义装饰器实现了@user3016183方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|845599|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|code-block|syntax|javascript|845600|我想有一天这可能会帮助到某个人。|845601|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I implemented @user3016183 method using a custom decorator:

<pre><code>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
</code></pre>

I thought that might help someone one day...

blocks|key|845649|text|几天前我遇到了同样的情况，我的解决方案是在模块中定义一个函数来测试并模拟它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|845650|def+get_date_now():
++++return+datetime.datetime.now()|code-block|syntax|javascript|845651|今天我发现了FreezeGun，它似乎很好地报道了这个案例。|offset|length|845652|from+freezegun+import+freeze_time
import+datetime
import+unittest


@freeze_time("2012-01-14")
def+test():
++++assert+datetime.datetime.now()+==+datetime.datetime(2012,+1,+14)|845653|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/spulec/freezegun^0|0|0|6|9|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@$I|X|J|Y|1|Z]]|A|$]]|$1|K|3|L|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

I faced the same situation a couple of days ago, and my solution was to define a function in the module to test and just mock that:

<pre><code>def get_date_now():
 return datetime.datetime.now()
</code></pre>

Today I found out about <a href="https://github.com/spulec/freezegun" rel="noreferrer">FreezeGun</a>, and it seems to cover this case beautifully

<pre><code>from freezegun import freeze_time
import datetime
import unittest


@freeze_time("2012-01-14")
def test():
 assert datetime.datetime.now() == datetime.datetime(2012, 1, 14)
</code></pre>

blocks|key|845688|text|对我来说最简单的方法就是这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|845689|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)|code-block|syntax|javascript|845690|此解决方案的注意事项：target_module中datetime+module的所有功能都将停止工作。|offset|length|style|CODE|845691|entityMap^0|0|0|B|D|P|F|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

The easiest way for me is doing this:

<pre><code>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)
</code></pre>

CAUTION for this solution: all functionality from <code>datetime module</code> from the <code>target_module</code> will stop working.

blocks|key|845733|text|可以在不添加side_effects的情况下模拟datetime模块中的函数|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|845734|import+mock
from+datetime+import+datetime
from+where_datetime_used+import+do

initial_date+=+datetime.strptime('2018-09-27',+"%25Y-%25m-%25d")
with+mock.patch('where_datetime_used.datetime')+as+mocked_dt:
++++mocked_dt.now.return_value+=+initial_date
++++do()|code-block|syntax|javascript|845735|entityMap^0|6|C|O|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

It's possible to mock functions from <code>datetime</code> module without adding <code>side_effects</code>

<pre><code>import mock
from datetime import datetime
from where_datetime_used import do

initial_date = datetime.strptime('2018-09-27', "%Y-%m-%d")
with mock.patch('where_datetime_used.datetime') as mocked_dt:
 mocked_dt.now.return_value = initial_date
 do()
</code></pre>

blocks|key|1060241|text|这里有另一种模拟datetime.date.today()的方法，它的另一个好处是其余的datetime函数可以继续工作，因为模拟对象被配置为包装原始的datetime模块：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1060242|from+unittest+import+mock,+TestCase

import+foo_module

class+FooTest(TestCase):

++++@mock.patch(f'{foo_module.__name__}.datetime',+wraps=datetime)
++++def+test_something(self,+mock_datetime):
++++++++#+mock+only+datetime.date.today()
++++++++mock_datetime.date.today.return_value+=+datetime.date(2019,+3,+15)
++++++++#+other+calls+to+datetime+functions+will+be+forwarded+to+original+datetime|code-block|syntax|javascript|1060243|请注意mock.patch()的wraps=datetime参数-当foo_module使用除date.today()之外的其他datetime函数时，它们将被转发到原始包装的datetime模块。|1060244|entityMap^0|8|L|18|8|24|8|0|0|3|C|G|E|Y|A|1B|C|1S|8|2G|8|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]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|N|$]]

Here's another way to mock <code>datetime.date.today()</code> with an added bonus that the rest of <code>datetime</code> functions continue to work, as the mock object is configured to wrap the original <code>datetime</code> module:

<pre><code>from unittest import mock, TestCase

import foo_module

class FooTest(TestCase):

 @mock.patch(f'{foo_module.__name__}.datetime', wraps=datetime)
 def test_something(self, mock_datetime):
 # mock only datetime.date.today()
 mock_datetime.date.today.return_value = datetime.date(2019, 3, 15)
 # other calls to datetime functions will be forwarded to original datetime
</code></pre>

Note the <code>wraps=datetime</code> argument to <code>mock.patch()</code> – when the <code>foo_module</code> uses other <code>datetime</code> functions besides <code>date.today()</code> they will be forwarded to the original wrapped <code>datetime</code> module.

blocks|key|845827|text|对于那些在pytest-mock中使用pytest的人(更多关于pytest-mock的信息，在最后)，这里是我模拟datetime.datetime.now()的方式，这与最初的问题非常相似。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|845828|test_get_now(mocker):
++++datetime_mock+=+mocker.patch("blackline_accounts_import.datetime",)
++++datetime_mock.datetime.now.return_value=datetime.datetime(2019,3,11,6,2,0,0)
++++
++++now+==+function_being_tested()++#+run+function

++++assert+now+==+datetime.datetime(2019,3,11,6,2,0,0)|code-block|syntax|javascript|845829|本质上，mock必须设置为返回指定的日期。你不能直接修补datetime的对象。|845830|Pytest-mock是一个使mock对象成为fixture的库。更多细节可以在here上找到|845831|entityMap|0|LINK|mutability|MUTABLE|url|https://pypi.org/project/pytest-mock/|1^0|1M|N|5|B|0|0|0|0|14|4|1|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]]|D|@$9|10|A|11|1|12]]|E|$]]|$1|F|3|G|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|15|8|@]|D|@$9|16|A|17|1|18]]|E|$]]|$1|O|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]|W|$5|R|S|T|E|$U|V]]]]

For those of you using pytest with <a href="https://pypi.org/project/pytest-mock/" rel="nofollow noreferrer">pytest-mock</a> (more info on pytest-mock at the end) here is how I mocked <code>datetime.datetime.now()</code> which is very similar to the original question.
<pre><code>test_get_now(mocker):
 datetime_mock = mocker.patch(&quot;blackline_accounts_import.datetime&quot;,)
 datetime_mock.datetime.now.return_value=datetime.datetime(2019,3,11,6,2,0,0)
 
 now == function_being_tested() # run function

 assert now == datetime.datetime(2019,3,11,6,2,0,0)
</code></pre>
Essentially the mock has to be set to return the specified date. You aren't able to patch over datetime's object directly.
Pytest-mock is a library that makes a mock object a fixture. More detail can be found <a href="https://pypi.org/project/pytest-mock/" rel="nofollow noreferrer">here</a>

blocks|key|1060321|text|为此，我将datetime作为realdatetime导入，并将模拟中需要的方法替换为真正的方法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1060322|import+datetime+as+realdatetime

@mock.patch('datetime')
def+test_method(self,+mock_datetime):
++++mock_datetime.today+=+realdatetime.today
++++mock_datetime.now.return_value+=+realdatetime.datetime(2019,+8,+23,+14,+34,+8,+0)|code-block|syntax|javascript|1060323|entityMap^0|5|8|F|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

I made this work by importing <code>datetime</code> as <code>realdatetime</code> and replacing the methods I needed in the mock with the real methods:

<pre><code>import datetime as realdatetime

@mock.patch('datetime')
def test_method(self, mock_datetime):
 mock_datetime.today = realdatetime.today
 mock_datetime.now.return_value = realdatetime.datetime(2019, 8, 23, 14, 34, 8, 0)
</code></pre>

blocks|key|845884|text|您可以使用以下命令模拟datetime：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|845885|在模块sources.py中|845886|import+datetime


class+ShowTime:
++++def+current_date():
++++++++return+datetime.date.today().strftime('%25Y-%25m-%25d')|code-block|syntax|javascript|845887|在你的tests.py中|845888|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')|845889|entityMap^0|B|8|0|3|A|0|0|3|8|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|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|Y|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

You can mock <code>datetime</code> using this:

In the module <code>sources.py</code>:

<pre><code>import datetime


class ShowTime:
 def current_date():
 return datetime.date.today().strftime('%Y-%m-%d')

</code></pre>

In your <code>tests.py</code>:

<pre><code>from unittest import TestCase, mock
import datetime


class TestShowTime(TestCase):
 def setUp(self) -&gt; 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')
</code></pre>

blocks|key|1060395|text|CPython实际上使用纯Python+Lib/datetime.py和C优化的Modules/_datetimemodule.c实现了datetime模块。C优化版本无法打补丁，但纯Python版本可以打补丁。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1060396|在Lib/datetime.py中的纯Python实现的底部是以下代码：|1060397|try:
++++from+_datetime+import+*++#+<--+Import+from+C-optimized+module.
except+ImportError:
++++pass|code-block|syntax|javascript|1060398|这段代码导入了所有经过C优化的定义，并有效地替换了所有纯Python定义。我们可以通过执行以下操作强制CPython使用datetime模块的纯Python实现：|1060399|import+datetime
import+importlib
import+sys

sys.modules["_datetime"]+=+None
importlib.reload(datetime)|1060400|通过设置sys.modules["_datetime"]+=+None，我们告诉Python忽略C优化的模块。然后，我们重新加载模块，这会导致从_datetime导入失败。现在，纯Python定义仍然存在，并且可以正常打补丁。|style|CODE|1060401|如果您使用的是Pytest，那么在conftest.py中包含上面的代码片段，您就可以正常地修补datetime对象了。|1060402|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/python/cpython/blob/master/Lib/datetime.py|1|https://github.com/python/cpython/blob/master/Modules/_datetimemodule.c|2|3|https://docs.pytest.org/|4|https://docs.pytest.org/en/stable/plugins.html^0|K|F|0|14|P|1|0|1|F|2|0|0|0|0|4|V|20|9|0|1C|8|7|6|3|H|B|4|0^^$0|@$1|2|3|4|5|6|7|19|8|@]|9|@$A|1A|B|1B|1|1C]|$A|1D|B|1E|1|1F]]|C|$]]|$1|D|3|E|5|6|7|1G|8|@]|9|@$A|1H|B|1I|1|1J]]|C|$]]|$1|F|3|G|5|H|7|1K|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|1L|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|1M|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|1N|8|@$A|1O|B|1P|Q|R]|$A|1Q|B|1R|Q|R]]|9|@]|C|$]]|$1|S|3|T|5|6|7|1S|8|@$A|1T|B|1U|Q|R]]|9|@$A|1V|B|1W|1|1X]|$A|1Y|B|1Z|1|20]]|C|$]]|$1|U|3|-4|5|6|7|21|8|@]|9|@]|C|$]]]|V|$W|$5|X|Y|Z|C|$10|11]]|12|$5|X|Y|Z|C|$10|13]]|14|$5|X|Y|Z|C|$10|11]]|15|$5|X|Y|Z|C|$10|16]]|17|$5|X|Y|Z|C|$10|18]]]]

CPython actually implements the datetime module using both a pure-Python <a href="https://github.com/python/cpython/blob/master/Lib/datetime.py" rel="nofollow noreferrer">Lib/datetime.py</a> and a C-optimized <a href="https://github.com/python/cpython/blob/master/Modules/_datetimemodule.c" rel="nofollow noreferrer">Modules/_datetimemodule.c</a>. The C-optimized version cannot be patched but the pure-Python version can.
At the bottom of the pure-Python implementation in <a href="https://github.com/python/cpython/blob/master/Lib/datetime.py" rel="nofollow noreferrer">Lib/datetime.py</a> is this code:
<pre><code>try:
 from _datetime import * # &lt;-- Import from C-optimized module.
except ImportError:
 pass
</code></pre>
This code imports all the C-optimized definitions and effectively replaces all the pure-Python definitions. We can force CPython to use the pure-Python implementation of the datetime module by doing:
<pre><code>import datetime
import importlib
import sys

sys.modules[&quot;_datetime&quot;] = None
importlib.reload(datetime)
</code></pre>
By setting <code>sys.modules[&quot;_datetime&quot;] = None</code>, we tell Python to ignore the C-optimized module. Then we reload the module which causes the import from <code>_datetime</code> to fail. Now the pure-Python definitions remain and can be patched normally.
If you're using <a href="https://docs.pytest.org/" rel="nofollow noreferrer">Pytest</a> then include the snippet above in <a href="https://docs.pytest.org/en/stable/plugins.html" rel="nofollow noreferrer">conftest.py</a> and you can patch <code>datetime</code> objects normally.

blocks|key|1060445|text|我们可以使用pytest-mock+(https://pypi.org/project/pytest-mock/)+mocker对象来模拟特定模块中的日期时间行为|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1060446|假设您想要模拟以下文件中的日期时间|1060447|#+File+path+-+source_dir/x/a.py
import+datetime

def+name_function():
+++++name+=+datetime.now()
+++++return+f"name_{name}"|code-block|syntax|javascript|1060448|在测试函数中，当测试运行时，mocker将被添加到函数中|1060449|def+test_name_function(mocker):
+++++mocker.patch('x.a.datetime')
+++++x.a.datetime.now.return_value+=+datetime(2019,+1,+1)

+++++actual+=+name_function()

+++++assert+actual+==+"name_2019-01-01"|1060450|entityMap|0|LINK|mutability|MUTABLE|url|https://pypi.org/project/pytest-mock/^0|J|11|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|11|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

We can use pytest-mock (<a href="https://pypi.org/project/pytest-mock/" rel="nofollow noreferrer">https://pypi.org/project/pytest-mock/</a>) mocker object to mock datetime behaviour in a particular module
Let's say you want to mock date time in the following file
<pre><code># File path - source_dir/x/a.py
import datetime

def name_function():
 name = datetime.now()
 return f&quot;name_{name}&quot;
</code></pre>
In the test function, mocker will be added to the function when test runs
<pre><code>def test_name_function(mocker):
 mocker.patch('x.a.datetime')
 x.a.datetime.now.return_value = datetime(2019, 1, 1)

 actual = name_function()

 assert actual == &quot;name_2019-01-01&quot;
</code></pre>

blocks|key|846011|text|对我来说，最好的方法是@Daniel+G和@frx08解决方案的组合：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|846012|class+Test_mock_date:
++++class+NewDate(datetime.datetime):
++++++++@classmethod
++++++++def+now(cls,+tz=None):
++++++++++++return+cls(2021,+5,+12)

++++def+test_mock_date(self):
++++++++with+patch('datetime.datetime',+new+=+self.NewDate):
++++++++++++assert+datetime.datetime.now()+==+datetime.datetime(2021,+5,+12,+0,+0)|code-block|syntax|javascript|846013|您可以看看下面这篇我写的关于如何使用MagicMock+https://medium.com/@camposer/d2113513b365的不同示例的中型文章|offset|length|846014|entityMap|0|LINK|mutability|MUTABLE|url|https://medium.com/@camposer/d2113513b365^0|0|0|S|15|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

The best approach for me is a combination of @Daniel G and @frx08 solutions:
<pre><code>class Test_mock_date:
 class NewDate(datetime.datetime):
 @classmethod
 def now(cls, tz=None):
 return cls(2021, 5, 12)

 def test_mock_date(self):
 with patch('datetime.datetime', new = self.NewDate):
 assert datetime.datetime.now() == datetime.datetime(2021, 5, 12, 0, 0)
</code></pre>
You can take a look at the following medium article I wrote with different examples about how to use MagicMock <a href="https://medium.com/@camposer/d2113513b365" rel="nofollow noreferrer">https://medium.com/@camposer/d2113513b365</a>

blocks|key|1060518|text|对于那些在测试类中使用补丁程序的人，下面是我如何成功修补datetime功能的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1060519|from+datetime+import+datetime
import+unittest
from+unittest.mock+import+Mock,+patch

#+Replace+with+the+proper+path+to+the+module+you+would
#+like+datetime+to+be+mocked
from+path.to.my_module

class+MyTestCases(unittest.TestCase):

++++def+setUp(self):
++++++++"""execute+on+class+instantiation"""
++++++++#+Record+both+times+at+the+same+moment
++++++++self.dt_now,+self.dt_utcnow+=+datetime.now(),+datetime.utcnow()

++++++++#+After+retrieving+real+(or+hardcoded+datetime+values),+
++++++++#+proceed+to+mock+them+in+desired+module
++++++++self.patch_datetime_functions()


++++def+patch_datetime_functions(self)+->+None:
++++++++"""
++++++++Patch+datetime.now()+and+datetime.utcnow()+to+prevent+issues+when
++++++++comparing+expected+dates
++++++++"""

++++++++#+Create+a+patcher
++++++++self.patcher_dt+=+patch(
++++++++++++'path.to.my_module'
++++++++)

++++++++#+Start+but+make+sure+cleanup+always+occurs
++++++++self.patcher_dt.start()
++++++++self.addCleanup(self.patcher_dt.stop)

++++++++#+Perform+the+actual+patch+–+use+lambdas+as+mock+functions
++++++++datetime_mock+=+Mock(wraps=datetime)
++++++++datetime_mock.now.return_value+=+self.dt_now
++++++++datetime_mock.utcnow.return_value+=+self.dt_utcnow

++++++++my_module.datetime+=+datetime_mock


++++#+Here's+what+it+will+look+like+when+testing:
++++def+some_test(self):
++++++++curr_dt+=+self.dt_now
++++++++returned_dt+=+my_module.datetime.utcnow()
++++++++
++++++++#+Compare+the+dates
++++++++self.assertEqual(curr_dt,+returned_dt,
++++++++++++'Datetime+values+should+be+equal'
++++++++)|code-block|syntax|javascript|1060520|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|$]]

For those using patchers in a test class, here's how I'm successfully patching datetime functionality:
<pre class="lang-py prettyprint-override"><code>from datetime import datetime
import unittest
from unittest.mock import Mock, patch

# Replace with the proper path to the module you would
# like datetime to be mocked
from path.to.my_module

class MyTestCases(unittest.TestCase):

 def setUp(self):
 &quot;&quot;&quot;execute on class instantiation&quot;&quot;&quot;
 # Record both times at the same moment
 self.dt_now, self.dt_utcnow = datetime.now(), datetime.utcnow()

 # After retrieving real (or hardcoded datetime values), 
 # proceed to mock them in desired module
 self.patch_datetime_functions()


 def patch_datetime_functions(self) -&gt; None:
 &quot;&quot;&quot;
 Patch datetime.now() and datetime.utcnow() to prevent issues when
 comparing expected dates
 &quot;&quot;&quot;

 # Create a patcher
 self.patcher_dt = patch(
 'path.to.my_module'
 )

 # Start but make sure cleanup always occurs
 self.patcher_dt.start()
 self.addCleanup(self.patcher_dt.stop)

 # Perform the actual patch – use lambdas as mock functions
 datetime_mock = Mock(wraps=datetime)
 datetime_mock.now.return_value = self.dt_now
 datetime_mock.utcnow.return_value = self.dt_utcnow

 my_module.datetime = datetime_mock


 # Here's what it will look like when testing:
 def some_test(self):
 curr_dt = self.dt_now
 returned_dt = my_module.datetime.utcnow()
 
 # Compare the dates
 self.assertEqual(curr_dt, returned_dt,
 'Datetime values should be equal'
 )

</code></pre>

Can anyone tell me why this isn't working?

<pre><code>&gt;&gt;&gt; import mock
&gt;&gt;&gt; @mock.patch('datetime.date.today')
... def today(cls):
... return date(2010, 1, 1)
...
&gt;&gt;&gt; from datetime import date
&gt;&gt;&gt; date.today()
datetime.date(2010, 12, 19)
</code></pre>

Perhaps someone could suggest a better way?

Trying to mock datetime.date.today(), but not working

Python

有人能告诉我为什么这个不起作用吗？>>> import mock>>> @mock.patch('datetime.date.today')... def today(cls):...  return date(2010, 1, 1)...>>> from datetime import date>>> date.to...

问尝试模拟datetime.date.today()，但不起作用
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问尝试模拟datetime.date.today()，但不起作用
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