Continuing the discussion from getIcon gone from Plone 5.1 without deprecation warning notice in Plone 5.0:
I just confirmed that deprecation warning messages are not shown when running tests.
is there any current way to add this feature?
this could be very useful in CI builds.
Yes, there is a switch on the testrunner I think, I'm on mobile right now, but yes, you can enable that.
I hope you're not driving... take your time 
In the Zope instance recipe you can set deprecation-warnings = on.
we already did that globally, remember?
is not working on tests.