how is merchant of venice a comedy?

Marriage and comedy go hand in hand in Shakespeare's world. By the time The Merchant of Venice is over, most of the characters are happily married except for Shylock and Antonio. Modern audiences will see tragic elements in how Shylock is treated but Elizabethan audiences would have likely felt that Shylock, being a Jew, got what he deserved. I can't help but think the Shakespeare intended for the audience to feel a little pathos for Shylock.