在python 2.7中使用修饰的方法调用进行模拟 [英] Issue mocking with a decorated method call in Python 2.7
问题描述
此代码:
import mock
from functools import wraps
def dec(f):
@wraps(f)
def f_2(*args, **kwargs):
pass
return f_2
class Example(object):
def __init__(self):
pass
@dec
def method_1(self, arg):
pass
def method_2(self, arg):
self.method_1(arg)
def test_example():
m = mock.create_autospec(Example)
Example.method_2(m, "hello")
m.method_1.assert_called_once_with("hello")
使用py.test产生此错误
produces this error with py.test
def test_example():
m = mock.create_autospec(Example)
> Example.method_2(m, "hello")
example.py:26:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
example.py:20: in method_2
self.method_1(arg)
anaconda2/envs/arctic/lib/python2.7/site-packages/mock/mock.py:1061: in __call__
_mock_self._mock_check_sig(*args, **kwargs)
anaconda2/envs/arctic/lib/python2.7/site-packages/mock/mock.py:227: in checksig
sig.bind(*args, **kwargs)
anaconda2/envs/arctic/lib/python2.7/site-packages/mock/mock.py:95: in fixedbind
return self._bind(args, kwargs)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <funcsigs.Signature object at 0x7f09b8685e10>, args = ('hello',), kwargs = {}, partial = False
def _bind(self, args, kwargs, partial=False):
'''Private method. Don't use directly.'''
arguments = OrderedDict()
parameters = iter(self.parameters.values())
parameters_ex = ()
arg_vals = iter(args)
if partial:
# Support for binding arguments to 'functools.partial' objects.
# See 'functools.partial' case in 'signature()' implementation
# for details.
for param_name, param in self.parameters.items():
if (param._partial_kwarg and param_name not in kwargs):
# Simulating 'functools.partial' behavior
kwargs[param_name] = param.default
while True:
# Let's iterate through the positional arguments and corresponding
# parameters
try:
arg_val = next(arg_vals)
except StopIteration:
# No more positional arguments
try:
param = next(parameters)
except StopIteration:
# No more parameters. That's it. Just need to check that
# we have no `kwargs` after this while loop
break
else:
if param.kind == _VAR_POSITIONAL:
# That's OK, just empty *args. Let's start parsing
# kwargs
break
elif param.name in kwargs:
if param.kind == _POSITIONAL_ONLY:
msg = '{arg!r} parameter is positional only, ' \
'but was passed as a keyword'
msg = msg.format(arg=param.name)
raise TypeError(msg)
parameters_ex = (param,)
break
elif (param.kind == _VAR_KEYWORD or
param.default is not _empty):
# That's fine too - we have a default value for this
# parameter. So, lets start parsing `kwargs`, starting
# with the current parameter
parameters_ex = (param,)
break
else:
if partial:
parameters_ex = (param,)
break
else:
msg = '{arg!r} parameter lacking default value'
msg = msg.format(arg=param.name)
raise TypeError(msg)
else:
# We have a positional argument to process
try:
param = next(parameters)
except StopIteration:
raise TypeError('too many positional arguments')
else:
if param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY):
# Looks like we have no parameter for this positional
# argument
> raise TypeError('too many positional arguments')
E TypeError: too many positional arguments
anaconda2/envs/arctic/lib/python2.7/site-packages/funcsigs/__init__.py:716: TypeError
是否有任何方法可以测试此代码的意图?如果删除装饰器，或者对method_1关键字args进行参数设置，那么它将神奇地起作用.我不确定该错误是在Mock本身，还是在funcsigs中，但显然存在缺陷.有解决方法吗?测试method_2调用method_1的另一种方法?
Is there any way to test what this code intends? If you remove the decorator, or if you make the arguments to method_1 keyword args, it magically works. I'm not sure if the bug is in Mock itself, or in funcsigs, but something is clearly amiss. Is there a workaround for this? Another way to test that method_2 calls method_1 ?
我应该提到，这是与模拟1.3.0一起提供的.出于某些原因，此代码在1.0.1中有效，但是我需要使用最新版本的模拟.
I should mention that this is with mock 1.3.0. This code works in 1.0.1 for some reason, but I need to use the latest version of mock.
更新
这有效:
def test_example():
m = mock.Mock(spec=Example)
m.method_1 = mock.Mock()
Example.method_2(m, "hello")
m.method_1.assert_called_once_with("hello")
推荐答案
从模拟1.1.0开始，框架开始深入检查方法签名.在
上查看更改日志.
From mock 1.1.0 the framework start to check deeply methods signature. Take a look to the changelog at
问题#17015:当具有规格时，Mock对象现在会在匹配调用时检查其签名，以便可以在位置或名称上匹配参数
Issue #17015: When it has a spec, a Mock object now inspects its signature when matching calls, so that arguments can be matched positionally or by name
现在，如果将f2()签名更改为def f_2(arg, *args, **kwargs)，它应该可以工作.
Now if you change f2() signature to def f_2(arg, *args, **kwargs) it should work.
这可能是一个新错误，签名检查无法正确理解该调用正确(至少兼容).我认为您可以提交错误并在此处发布票证链接.
Maybe that is a new bug where the signature check cannot understand correctly that the call is correct (at least compatible). I think that you can file a bug and post here the ticket link.
作为解决方法，您可以通过添加从method_1中删除自动指定
As workaround you can remove the autospeccing from method_1 by add
m.method_1 = mock.Mock()
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