>>> from unittest.mock import create_autospec
>>> def f(): pass
... 
>>> m = create_autospec(f)
>>> m.side_effect = [1, 2]
>>> m()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 3, in f
  File "/compile/py3k-cpython/Lib/unittest/mock.py", line 872, in __call__
    return _mock_self._mock_call(*args, **kwargs)
  File "/compile/py3k-cpython/Lib/unittest/mock.py", line 931, in _mock_call
    result = next(effect)
TypeError: 'list' object is not an iterator

This illustrates the difference:

>>> from mock import Mock, create_autospec
>>> some_list = [1, 2, 3]
>>> m = Mock()
>>> m.side_effect = some_list
>>> m.side_effect
<listiterator object at 0x1004ab7d0>
>>> m2 = create_autospec(lambda: None)
>>> m2.side_effect = some_list
>>> m2.side_effect
[1, 2, 3]


When setting a side_effect on a function (created by create_autospec) the side_effect setter is not used - so turning the list into an iterator needs to be done on first use instead.

Working on this.

Patch along with a test for the same.

Version 2 of the patch, with typo fixed also one more addition test to check callable side effect in create_autospec.

Michael, a patch including tests is ready for this issue.

Can you explain why we need to check for the call_count here? I don't understand why this is needed.

New patch with fix in proper place for side_effect for functions (includes test case).

New changeset 1e3c64470629 by Michael Foord in branch '3.4':
Issue 17826. Setting an iterable side_effect on a mock created by create_autospec now works
http://hg.python.org/cpython/rev/1e3c64470629