Since we moved to pytest 4.0, we have warnings summary at the end of the build.

Here is example summary:

00:10:06.166 =============================== warnings summary ===============================
00:10:06.167 /home/jenkins/workspace/vdsm_master_check-patch-fc28-x86_64/vdsm/lib/vdsm/storage/mailbox.py:73
00:10:06.168   /home/jenkins/workspace/vdsm_master_check-patch-fc28-x86_64/vdsm/lib/vdsm/storage/mailbox.py:73: DeprecationWarning: fromstring() is deprecated. Use frombytes() instead.
00:10:06.171     _zeroCheck = checksum(EMPTYMAILBOX, CHECKSUM_BYTES)
...

You can see complete warnings here:
https://jenkins.ovirt.org/job/vdsm_master_check-patch-fc28-x86_64/2413/consoleFull

We have only few warnings, but they are repeated a lot.

Nir