I have ball locks, but the same theory applies.
I pressurize to 50 PSI, then coat the posts, lid seal, and release valve with soapy water. If I see bubbles, I know it's not sealing. If I don't see bubbles, I disconnect it and let it sit for a few days. If it's still holding 50 PSI after a few days, I figure it's good to go.
Added: Wow! An HBT dogpile!