如何模拟一个装饰函数
问题描述
出于测试原因,我需要能够模拟在其他地方使用的装饰的内部/原始功能:
For testing reasons, I need to be able to mock the inner/original function of a decorated one which is used somewhere else:
在 mydecorator.py 中:
In mydecorator.py:
def my_decorator(f):
def wrapped_f():
print "decorated"
f()
return wrapped_f
@my_decorator
def function_to_be_mocked():
print 'original'
def function_to_be_mocked_undecorated():
print 'original'
def run_decorated():
function_to_be_mocked()
def run_undecorated():
decorated_funtion = my_decorator(function_to_be_mocked_undecorated)
decorated_funtion()
如您所见,我有几个版本的原始函数 function_to_be_mocked,一个带有装饰器 my_decorator,另一个是裸".运行器函数 run_decorated() 调用 function_to_be_mocked 的修饰版本, run_undecorated() 调用未修饰版本并手动"应用修饰器.两者的结果是一样的:
As you can see, I have several versions of the original function function_to_be_mocked, one with the decorator my_decorator and one 'naked'. The runner function run_decorated() calls the decorated version of function_to_be_mocked and run_undecorated() calls the undecorated version and applies the decorator 'manually'. The result of both are the same:
decorated
original
现在我想测试 runner 函数,但我需要模拟原始函数 function_to_be_mocked 并且模拟的版本应该被装饰:
Now I want to test the runner function but I need to mock the original function function_to_be_mocked but also the mocked version should be decorated:
import unittest
import mydecorator
from mock import patch
def mock_function():
print 'mockified'
class Test(unittest.TestCase):
@patch('mydecorator.function_to_be_mocked_undecorated')
def test_undecorated_mocked(self, mock_function_to_be_mocked_undecorated):
mydecorator.function_to_be_mocked_undecorated = mock_function
mydecorator.run_undecorated()
assert 1==0
@patch('mydecorator.function_to_be_mocked')
def test_decoratorated_mocked(self, mock_function_to_be_mocked):
mydecorator.function_to_be_mocked = mock_function
mydecorator.run_decorated()
assert 1==0
这对于未修饰的版本 test_undecorated_mocked 可以正常工作:
This works as expected for the undecorated version test_undecorated_mocked:
decorated
mockified
但装饰版给出:
mockified
所以装饰器消失了.
是否可以让装饰版本以与未装饰版本相同的方式工作,其中手动"应用装饰器?
Is it possible to get the decorated version working in the same way as the undecorated version, where the decorator is applied 'manually'?
我尝试在装饰器中暴露内部函数,但没有成功.
I tried to expose the inner function in the decorator without success.
我看到了这个问题 你如何模拟一个在单元测试中应用了装饰器的函数?但这对我没有帮助.
I saw this question How do you mock a function which has decorator apply to it in a unit test? but this doesn't help me.
解决方案
Python在加载模块时应用装饰器,所以在test_decoratorated_mocked<中设置
function_to_be_mocked
为mock_function
/code> 确实会将该函数更改为未修饰的函数.
Python applies the decorator when loading the module so setting function_to_be_mocked
to mock_function
in test_decoratorated_mocked
would indeed change that function into an undecorated function.
如果要模拟 function_to_be_mocked
,则需要再次手动添加装饰器:
You'd need to manually add the decorator again if you wish to mock function_to_be_mocked
:
mydecorator.function_to_be_mocked = mydecorator.my_decorator(mock_function)
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