When writing unit tests it is sometimes useful to check that a log message was created. Python provides TestCase.assertLogs for this purpose but this does not work with lsst.log. It would be useful to allow unit tests to temporarily forward lsst.log messages to Python logging so that they could be tested.

This would have to ensure that DM-15201 does not cause a logging loop.

Ideally C++ log4cxx messages could be forwarded but it seems much easier to focus on Python lsst.log messages.