I would never want to risk an artisan created (or antique) katana to that test. To me, that would be like testing the Mona Lisa to see if it is fireproof.
I doubt that anyone would test a real shinken like that. They would probably use a modern Chinese copy, although that somewhat skews the authenticity.
I can't afford a real Japanese sword, even a modern one, so I bought a pretty good Chinese copy from Paul Chen. It is 8260 spring steel with a real hamon.