I've got:

platform darwin -- Python 3.9.13, pytest-7.2.0, pluggy-1.0.0
rootdir: /Users/roy/dev/dyk-tools, configfile: src/pages/pytest.ini
plugins: mock-3.10.0, socket-0.5.1

When I run the following:

def test_ip(mocker):
    mock_IPv4Address = mocker.patch('ipaddress.IPv4Address', autospec=True)
    ip = mock_IPv4Address('1.2.3.4')
    assert mock_IPv4Address.xxyyzz


def test_site(mocker):
    mock_Site = mocker.patch('pywikibot.Site', autospec=True)
    site = mock_Site('en', 'wikipedia')
    assert site.xxyyzz

test_ip() fails, as I expect it to, with AttributeError: Mock object has no attribute 'xxyyzz'. But, test_site() passes. WTF? Why does it not also fail with the same error?