Utah Avalanche Center Shovel Tilt Test
Testing for snow stability while backcountry skiing is an on going effort. It's not like you dig one pit and call it good. I'm continually probing the snow throughout a tour.
There are many tests that you can do, the most widely used being the shovel compression test. But when the snow surface is powder the compression test may eliminate the layers that may be suspect.
Here is a video that the Utah Avalanche Center put together showing the shovel tilt test which although relatively new it has shown conclusive results. (conclusive of course is relative to the skier and the skiing objective) The UAC is continually getting better and better with their forecasts and the knowledge they share with the backcountry community.