How can I patch / mock logging.getlogger()

You can use patch.object() on the actual logging object. that lets you verify that you’re using the correct logger too:

logger = logging.getLogger('path.to.module.under.test')
with mock.patch.object(logger, 'debug') as mock_debug:
    run_code_under_test()
    mock_debug.assert_called_once_with('Init')

Alternatively, if you’re using Pytest, then it already has a fixture that captures logs for you:

def test_bar(caplog):
    with caplog.at_level(logging.DEBUG):
        run_code_under_test()
    assert "Init" in caplog.text
    # or, if you really need to check the log-level
    assert caplog.records[-1].message == "Init"
    assert caplog.records[-1].levelname == "DEBUG"

More info in the pytest docs on logging