How to check if cabinets are wood or laminate
Easiest way is to cut one in half, but I'll assume you want to do this non-destructively. 

One way that you can check is to remove one of the hinges.  If it's a recessed hinge you'll find yourself looking at the inside of the door.  If it isn't recessed you can examine the screw holes and/or probe them with a dental pick.