A colleague wanted to mock a Journal object which both has callable methods and works as an iterator itself. So it works like this:
j = Journal()
for line in j:
We mocked it like this, to be able to pass an actual list of expected values the function will iterate over:
mock_journal = mock.Mock()
mock_journal.__next__ = mock.Mock(side_effect=[1,2,3,4])
mock_journal.__iter__ = mock.Mock(return_value=mock_journal)
for i in mock_journal:
# I don't call any methods in mock_journal, but I could,
# and could then assert they were called.
So mock_journal is both a mock proper, where methods can be called (and then asserted on), and an iterable, which when called repeatedly will yield elements of the __next__ side_effect.