Question

I must say I am new to python mock.
I have an side_effect iterator:

myClass.do.side_effect = iter([processStatus, memoryStatus, processStatus, memoryStatus, processStatus, memoryStatus, processStatus, memoryStatus])

The above works as expected and the test cases pass

But I am looking for a better way to write this.
I tried [....]*4 which did not work.

How should I do it? Simply, making the iterator to start from the beginning once it come to the end.

Answer 1

I think you can use itertools.cycle here, if you want ‘over and over again’:

>>> s = range(3)
>>> s
[0, 1, 2]
>>> from itertools import cycle
>>> c = cycle(s)
>>> c
<itertools.cycle object at 0xb72697cc>
>>> [next(c) for i in range(10)]
[0, 1, 2, 0, 1, 2, 0, 1, 2, 0]
>>> c = cycle(['pS', 'mS'])
>>> [next(c) for i in range(10)]
['pS', 'mS', 'pS', 'mS', 'pS', 'mS', 'pS', 'mS', 'pS', 'mS']

Or, as @mgilson notes, if you want a finite number of 2-element terms (I’m not completely sure of what data format you need):

>>> from itertools import repeat
>>> repeat([2,3], 3)
repeat([2, 3], 3)
>>> list(repeat([2,3], 3))
[[2, 3], [2, 3], [2, 3]]

But as noted in the comments, iter([1,2,3]*n) should work too.