How do you test a dog to see if they rip apart blankets or pillows?

More likely in puppies. They need things to chew on and ruin. Dog toys fit the bill usually. It's also good to dog proof the hone, with shoes and blankets and pillows out of reach. Remember they aren't going this to wreck your things or lash out at you. It's usually a sign of boredom or that they are having sore teeth.