[TIP] removing attributes and dictionary keys using mock.patch

Chris Withers chris at simplistix.co.uk
Fri Dec 5 10:34:36 PST 2014

> On 5 Dec 2014, at 18:19, Michael Foord <michael at voidspace.org.uk> wrote:
>> On 05/12/14 16:54, Chris Withers wrote:
>> Hi All,
>> I'm excited to see how far mock.patch has come, mainly as I'm hoping I can deprecate testfixtures.Replacer as a result ;-)
>> The only think it looks like Mock can't currently do is remove attributes or dictionary items:
>> https://pythonhosted.org/testfixtures/mocking.html#removing-attributes-and-dictionary-items 
>> Michael, would you be up for me adding that to Mock or is it a non-starter?
>> I'd be happy to approach using either a delete=True option to patch() and patch.dict() (I don't really understand what patch.object does, so can't comment...) or, alternatively, a not_there or deleted marker object like I did in testfixtures.
>> Lemme know your thoughts...
> So, removing an attribute is not possible in the *general* case. In the specific case of it being an instance attribute you can remove it from the object dictionary.

Yeah, my take on it is "anything where delattr works"...

> In which case just having patch.dict support key removal would work.

...or delitem in this case.

> I don't have any objection if the api can be clean and the implementation isn't horrible.

Do you have a preference for a marker object (like testfixtures uses) or a keyword param (such as delete=True)?

A whole separate set of decorators/context managers/etc seems like overkill, so I hope that's not your preference ;-)


More information about the testing-in-python mailing list