The following test code unexpectedly passes.

import logging
import unittest

LOG_FORMAT = '%(levelname)-10s %(asctime)s: %(message)s'


def set_up_logger(app_name, level=logging.INFO, file="test.log"):
    formatter = logging.Formatter(LOG_FORMAT)
    log = logging.getLogger(app_name)
    # The next line lets the test pass
    log.setLevel(level)
    return log

logger = set_up_logger(__name__)

class TestLogging(unittest.TestCase):
    def test_logging(self):
        with self.assertLogs(level=logging.WARNING):
            logger.info('foo')

Based on discussion at https://stackoverflow.com/questions/64141681/any-level-of-logging-lets-assertlogs-pass, it appears that I need to pass in the logger which is going to be doing the logging.  

Doing so would make the test over-specific and fragile.  The requirement is that a warning be logged, not that a specific logger issue the warning.

This was verified with Python 3.8.5 on a Mac, but probably exists in most/all other versions.