Is it legal for business to hold "try outs" for a job without compensating any kind of monetary wage?

My cousin recently applied for a job in a mall at a sandwich shop. This is the owners first time opening a business. After she applied, the owner called her back for "try outs" along with a few other people. She was there for a couple hours, but never got compensated for her time working or "trying out". My concern is that she is a minor working in the state of California, who doesn't have a grasp on labor laws.