testing power ic

[oel]

Is there a way I can test a cobba ic or power ic using a tester if its good or defective? Before, I buy 4 pcs power ic sealed in plastic. not know all of them are defective. The seller no longer accept it when i return it back. they say the ball already ruin.

so the best way is to test it before u buy it. BUT HOW?

pls help.

:(