When Raistlin approaches his Test at the Tower of the High Sorcery,
He is almost about to fail, his life force shattered beyond saving. Then, the wizard-lich Fistandantilus offers him a deal: his life force in exchange for the power to pass the Test. Raistlin accepts, passes the Test, and then reneges on his bargain with Fistandantilus.
Then, years later, when Palin is taking his Test, Dalamar calls an illusion of Raistlin and
Raistlin himself shows up and chats with Palin.
I haven't been able to find much else about other wizards Tests' details.
Are there any other wizards known for being able to call on supernatural or external help during their Test of the High Sorcery?