On Python3, logging warning are displayed when running test
For the SQLite backend, we have many warning about TableHandler features not supported at all. So when the tests are run on SQLite, those warnings are displayed but they don't provide any interesting information and more over they make looking at the tests an harder task because of all this noise.
See https://drone.tryton.org/trypod.tryton.org/tryton/trytond/default/83b07c8b2c2d2d21c8f5650b10242b6a8ac9ca43
So I propose to replace those logging.warn by warnings.warn using a fixed text so each one is printed only once. But only for basic missing feature but not for migration issues. Also there is a facility to integrate such warnings into the logging: https://docs.python.org/2/library/logging.html#integration-with-the-warnings-module