Hmm, okay, things I didn't know about MagicMock and I'm not sure I like ;-) :

>>> m = MagicMock()
>>> list(iter(m))
[]

However, what happens if you change the above line to:

I'm not sure it makes any difference, but mainly 'cos of the weird behaviour I started with an example of ;-)

Here's some playing around in a Python 3.12 interpreter that might give more of a feel for what I'm trying to communicate:

>>> from unittest.mock import MagicMock
>>> m = MagicMock()
>>> m.__iter__
<MagicMock name='mock.__iter__' id='4307758752'>
>>> m.__iter__.return_value = []
>>> iter(m)
<list_iterator object at 0x10088f8b0>
>>> list(iter(m))
[]
>>> list(iter(m)) is m.__iter__.return_value
False
>>> m.__iter__.return_value = [1, 2, 3]
>>> list(iter(m))
[1, 2, 3]

I added one more test with the behavior you are showing here. I executed these two tests

    def test_magic_mock_resets_manual_mocks(self):
        mm = MagicMock()
        mm.__iter__ = MagicMock(return_value=iter([1]))
        mm.custom = MagicMock(return_value=2)
        self.assertEqual(list(iter(mm)), [1])
        self.assertEqual(mm.custom(), 2)

        mm.reset_mock(return_value=True)
        self.assertEqual(list(iter(mm)), [])
        self.assertIsInstance(mm.custom(), MagicMock)

    def test_magic_mock_resets_manual_mocks_empty_iter(self):
        mm = MagicMock()
        mm.__iter__.return_value = []
        self.assertEqual(list(iter(mm)), [])

        mm.reset_mock(return_value=True)
        self.assertEqual(list(iter(mm)), [])

on main (with no changes from this PR) and it was also successful.

Should I cover anything else?

Ah, I think this is where I got confused; the docs aren't great here. I believe the intention may be that return_value is only a boolean, or it may be that it's intended as a way to provide a new value.

If you feel inclined, it'd be good to clarify the docs on this.

Sure!

Ah, I think this is where I got confused; the docs aren't great here. I believe the intention may be that return_value is only a boolean, or it may be that it's intended as a way to provide a new value.

If you feel inclined, it'd be good to clarify the docs on this.