The best way to test the program is with an insignificant but noticeable test. Something like changing his hair color.
Bruce enters the program and changes himself into a blond. He gets up to go find a mirror and sees the change for himself. He almost gasps. It works.
He goes back to his computer and turns his hair back to its original color.
Now that he established the authenticity of the program's power, he thinks about what else he can do with it.