[TIP] mock os.walk

[Andrea Crotti]

I wrote in the other thread but I'd better start a new one.
I simply want to mock os.walk making it iterates over a list.

So what's wrong with the following I really don't get it?

from mock import MagicMock, patch
from os import walk

test_dir = [
     ('root', ['d1, .git'], []),
]


my_mock = MagicMock()
my_mock.__iter__ = iter(test_dir)


@patch('os.walk', new=my_mock)
def myfun():
     for r, ds, df in walk('.'):
         print(df)


I get a

Traceback (most recent call last):
   File "mock_walk.py", line 10, in <module>
     my_mock.__iter__ = iter(test_dir)
   File 
"/home/andrea/.local/lib/python2.7/site-packages/mock-0.8.0beta4-py2.7.egg/mock.py", 
line 795, in __setattr__
     value = mocksignature(value, real, skipfirst=True)
   File 
"/home/andrea/.local/lib/python2.7/site-packages/mock-0.8.0beta4-py2.7.egg/mock.py", 
line 320, in mocksignature
     signature, func = _getsignature(func, skipfirst)
   File 
"/home/andrea/.local/lib/python2.7/site-packages/mock-0.8.0beta4-py2.7.egg/mock.py", 
line 153, in _getsignature
     func = func.__call__
AttributeError: 'listiterator' object has no attribute '__call__'


but what I don't understand is why we would need the call method, isn't 
the for loop triggering the __iter__ only?