Answer:
Amir and Hassan are somehow best friends who even had their spot under the pomegranate tree under which Amir will read to Hassan , since Hassan isn't going to school as a servant's son however the differences in their background create some split between them.
Why does Amir constantly test Hassan's loyalty?
Amir doesn't believe that a person can have such amount of loyalty mostly because he is not even confident in himself due to the way his father treat him.
It is hard for him to trust people around him since he can't see that love and loyalty from his father hence he doubt that Hassan can possess such.
This has made Amir to be self centred and egocentric , he even admit to getting Hassan into trouble but still doesn't see that as an issue but just a game.
So he is always testing Hassan because he just doesn't believe in love because of how he is being raised.
After the kite running tournament, why does Amir no longer want to be Hassan’s friend?
Amir won the kit and Hassan runs to get it for him but he doesn't return immediately when Amir goes to check up on him, he finds him being gang raped .
He is afraid to help and instead he hides away due to his failure to help Hassan he is haunted by the guilt.
This was a horrible thing that happened to his friend , very unjust thing but he can't help his friend he knows based on how loyal Hassan is he would have intervened and done something to help Amir so the guilt is eating him away and he chooses to stay away from Hassan.
This test the themes of loyalty and support that one can give to their friends irrespective of the situation , one friend is giving his loyalty to support his friend whilst the other fails to do so.
