I have a class:
class MyClass(object):
@property
def myproperty(self):
return 'hello'
Using mox
and py.test
, how do I mock out myproperty
?
I've tried:
mock.StubOutWithMock(myclass, 'myproperty')
myclass.myproperty = 'goodbye'
and
mock.StubOutWithMock(myclass, 'myproperty')
myclass.myproperty.AndReturns('goodbye')
but both fail with AttributeError: can't set attribute
.
When stubbing out class attributes mox
uses setattr
. Thus
mock.StubOutWithMock(myinstance, 'myproperty')
myinstance.myproperty = 'goodbye'
is equivalent to
# Save old attribute so it can be replaced during teardown
saved = getattr(myinstance, 'myproperty')
# Replace the existing attribute with a mock
mocked = MockAnything()
setattr(myinstance, 'myproperty', mocked)
Note that because myproperty
is a property getattr
and setattr
will be invoking the property's __get__
and __set__
methods, rather than actually "mocking out" the property itself.
Thus to get your desired outcome you just go one step deeper and mock out the property on the instance's class.
mock.StubOutWithMock(myinstance.__class__, 'myproperty')
myinstance.myproperty = 'goodbye'
Note that this might cause issues if you wish to concurrently mock multiple instances of MyClass with different myproperty
values.