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|
import inspect
from mock import Mock
__all__ = ('mocksignature', 'MagicMock')
"""
extendmock adds additional features to the mock module.
The mocksignature function creates wrapper functions that call a mock whilst
preserving the signature of the original function.
Note that when a function signature is mocked with mocksignature it will *always* be
called with positional arguments and not keyword arguments (except where it
collects arguments with \*\*). Defaults will explicitly be supplied where the function
is called with missing arguments (as normal).
MagicMock is a class that adds magic method support to Mock. You add magic methods
to mock instances in the same way you mock other attributes::
mock = Mock()
mock.__repr__ = lambda self: 'some string'
Note that functions (or callable objects like a Mock instance) that are used for
magic methods must take self as the first argument.
The only unsupported magic methods (that I'm aware of) are:
* Used by Mock: __init__, __new__, __getattr__, __setattr__, __delattr__
* Rare: __dir__,
* Can cause bad interactions with other functionality:
- __reversed__, __missing__, __del__, __unicode__, __getattribute__
- __get__, __set__, __delete__
* Context manager methods are not directly supported (__enter__ and __exit__) as
Python doesn't lookup these methods on the class as it should (in Python 2.5 / 2.6
anyway).
For more examples of how to use mocksignature and MagicMock see the tests.
"""
# getsignature and mocksignature heavily "inspired" by
# the decorator module: http://pypi.python.org/pypi/decorator/
# by Michele Simionato
DELEGATE = MISSING = object()
def getsignature(func):
assert inspect.ismethod(func) or inspect.isfunction(func)
regargs, varargs, varkwargs, defaults = inspect.getargspec(func)
# instance methods need to lose the self argument
im_self = getattr(func, 'im_self', None)
if im_self is not None:
regargs = regargs[1:]
argnames = list(regargs)
if varargs:
argnames.append(varargs)
if varkwargs:
argnames.append(varkwargs)
assert '_mock_' not in argnames, ("_mock_ is a reserved argument name, can't mock signatures using _mock_")
signature = inspect.formatargspec(regargs, varargs, varkwargs, defaults, formatvalue=lambda value: "")
return signature[1:-1]
def mocksignature(func, mock):
signature = getsignature(func)
src = "lambda %(signature)s: _mock_(%(signature)s)" % {'signature': signature}
funcopy = eval(src, dict(_mock_=mock))
funcopy.__name__ = func.__name__
funcopy.__doc__ = func.__doc__
funcopy.__dict__.update(func.__dict__)
funcopy.__module__ = func.__module__
funcopy.func_defaults = func.func_defaults
return funcopy
class MagicMock(Mock):
pass
magic_methods = [
("lt le gt ge eq ne", NotImplemented),
("getitem setitem delitem", TypeError),
("len contains iter", TypeError),
("hash repr str", DELEGATE),
("nonzero", True),
("divmod neg pos abs invert", TypeError),
("complex int long float oct hex index", TypeError)
]
numerics = "add sub mul div truediv floordiv mod lshift rshift and xor or"
inplace = ' '.join('i%s' % n for n in numerics.split())
right = ' '.join('r%s' % n for n in numerics.split())
magic_methods.extend([
(numerics, NotImplemented), (inplace, NotImplemented), (right, NotImplemented)
])
def get_method(name, action):
def func(self, *args, **kw):
real = self.__dict__.get(name, MISSING)
if real is not MISSING:
return real(self, *args, **kw)
if action is NotImplemented:
return NotImplemented
elif action is TypeError:
raise action
elif action is DELEGATE:
return getattr(Mock, name)(self, *args, **kw)
return action
func.__name__ = name
return func
for methods, action in magic_methods:
for method in methods.split():
name = '__%s__' % method
setattr(MagicMock, name, get_method(name, action))
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