Comment 41 for bug 1813147

It's the notification listener in oslo.messaging that logs the traceback, that's why it wasn't the CastAsCall thing I was expecting:

https://github.com/openstack/oslo.messaging/blob/558fc5f4e8aa4b8553ee7522d21cc1583e10a849/oslo_messaging/notify/listener.py#L188

So yeah we can't really do much about that since these are notification tests. We could potentially stub out LOG.exception in the specific part of the test that triggers the fault, but that's pretty hacky.