Use a stringer. Once strung, pull i lightly but don't draw. Listen for strange creaks and groans.
If I were you, I would leave it strung up overnight. Next day do a half draw, then 3/4, then full draw and down.
If it survives all that, stry a shot. If it don't crack up you should be good to go.
Once you have it strung...'d leave it strung.