[TIP] Unit testing functions which call super

[Harry Percival]

Like this? https://gist.github.com/hjwp/44210e3e164bbb1fed18





On 13 August 2014 19:11, Harry Percival <harry.percival at gmail.com> wrote:

> If you know what the parent class is in advance, could you use mock.patch
> to stub out the parent method?
>
>
> On 13 August 2014 19:00, Marcin Tustin <Marcin.Tustin at dealertrack.com>
> wrote:
>
>>  Hi All,
>>
>>
>>
>> I’ve come across a method which I needed to add a unit test for, which
>> calls super, e.g.
>>
>>
>>
>> def foofunc(self):
>>
>>     x= do_some_stuff()
>>
>>     if x:
>>
>>         return x
>>
>>     return super(WhatevClass, self).foofunc()
>>
>>
>>
>> Now, I don’t want to integration test the whole stack of super foofunc
>> methods, just unit test that one, down to the super call.
>>
>>
>>
>> I’ve accomplished this with, in my test (excuse the 8 leading spaces):
>>
>>
>>
>> def setUp(self):
>>
>>         self.method_archive = {}
>>
>>         for klass in WhatevClass.__mro__[1:]:
>>
>>             # we use the class as its own sentinel
>>
>>             meth_or_klass = klass.__dict__.get('foofunc', klass)
>>
>>             if meth_or_klass != klass:
>>
>>                 self.method_archive[klass] = meth_or_klass
>>
>>                 del klass.foofunc
>>
>>         # now patch an arbitrary member of the mro to supply a dummy
>> foofunc
>>
>>         self.sentinel_klass = next(iter(self.method_archive))
>>
>>         self.mock_sentinel = mock.MagicMock()
>>
>>         self.sentinel_klass.foofunc = self.mock_sentinel
>>
>>
>>
>>
>>
>> And corresponding unpatching in tearDown.
>>
>>
>>
>> Is there any other approach which is standard, or objectively better?
>>
>>
>>
>> Thanks,
>>
>> Marcin
>>
>>
>>
>> *Marcin Tustin*
>> Senior Software Engineer
>>   ------------------------------
>>
>>
>> 1111 Marcus Avenue
>> Lake Success, NY 11042
>> dealertrack.com <https://www.dealertrack.com/>
>>
>> p 516.300.7072
>>
>>
>> *dealertrack **technologies*™
>>
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>
>
> --
> ------------------------------
> Harry J.W. Percival
> ------------------------------
> Twitter: @hjwp
> Mobile:  +44 (0) 78877 02511
> Skype:         harry.percival
>



-- 
------------------------------
Harry J.W. Percival
------------------------------
Twitter: @hjwp
Mobile:  +44 (0) 78877 02511
Skype:         harry.percival
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