Sorry for the delay, I was on holiday visiting family for the Memorial Day weekend, and finally have time to sit down and answer. The test was conducted on four zero degree double box end wrenches. The wrenches were 17/19mm and consisted of:
KTC M160-1719
Snap-on XDHFM1719
Deen DNML1719
Nepros NM11L1719
I'm not quite clear what the testing process was exactly, but it was a stress test until the tool failed/broke (they have pictures of the ring end split). I'm only guessing, but it is probably good to keep in mind the tools might not be rated for the following Nms (ft lbs):
17MM
KTC - 689.55 Nm; 508.58 ft lbs
Deen - 569.91 Nm; 420.34 ft lbs
Snap-on - 521.57 Nm; 384.69 ft lbs
Nepros - 548.67 Nm; 404.67 ft lbs
19MM
KTC - 856.30 Nm; 631.57 ft lbs
Deen - 646.11 Nm; 476.54 ft lbs
Snap-on - 686.05 Nm; 506 ft lbs
Nepros - 696.25 Nm; 513.52 ft lbs
They also have performed similar tests on ratchets, breaker bars, offset double box end wrenches, combination wrenches, hex wrenches (L-Keys), hex socket wrench, and screwdrivers. I would be more than happy to post results for those tests if the interest is there, just let me know what test you want.
[EDIT] I should add some tests include European manufacturers, so as to keep with the Tools of the old world theme.