I personally don't think a Rice, Colerain, or Green Mountain barrels need to be "Tested". Same goes for a Rayl, Long Hammock, or any other modern made barrel, JMO.
Funny that the best barrel makers in the world have been proofing barrels so long then. What do the companies in that list know that the rest of the world does not? Not saying their barrels are not usually great but proofing has been accepted as part of a barrels evolution from a billet or bar to a firearm for centuries.
food for thought:
With many materials including but not limited to bronze, iron, early steels 'proofing' serves not just to 'test' it for safety. Firing a heavy proof load actually serves to strengthen/improve resistance to future bursting.
Was a time when (and likely still) the best barrels were bored, loads heavy enough to enlarge the bore and OD were fired, even to the point of individual bulges and then the barrel would be bored to desired size, rifled, turned to a uniform profile.
proofing/firing with heavy loads has been recognized as a MAJOR contributor to creating safe barrels (as opposed to testing for a safe barrel) since the krauts started applying a bit of science and measuring to gun building in the mid 19th century.
I have no idea how any modern/ ( say post 1900) barrel material reacts to proofing, be nice if some barrel makers did though? We might end up with lighter barrels as one benefit. Those admirably thin light fowler walls and thin waist-ed rifles of old have a genesis in careful science.