as a nearly 800k mastery yasuo main, i can assure you that shen totally fucks yasuo. i've also played this matchup as shen.
you have 2 choices as shen- corrupting potion or armor?
personally i would go armor as shen, as you're mainly just going to be farming before your first back.
before your first back:
if yasuo tries jumping on you, activate your q, start attacking him, and if he still tries attacking you, taunt him, and continue to attack him until W wears off and he will lose the trade. then go back to farming. keep farming until either: you're very low and out of potions, yasuo backs, or if you have enough money for a bami's cinder or chain vest.
you want to try to get a bami's cinder ASAP. if you don't, go for a chain vest, and if you can afford it, a ruby crystal as well.
as you can probably guess, you're going to rush a sunfire cape first. once you finish that you should be able to start winning trades with ease.
if he's still a problem, continue to stack armor. ninja tabi, sunfire cape, and randuin's will make him completely unable to duel you.
if you need any more details about the matchup, just tell me