One test that any good technician would preform is a bounce test.
Put your knee on the bumper an lean on it until the car wont go down any further. Quickly get off the bumper and count how many times the body bounces. It should go up and down ONCE and then slowly return to its position. If it continues to bounce then the shocks/springs are bad and should be replaced. Do this to both the front and rear shocks.
Put your knee on the bumper an lean on it until the car wont go down any further. Quickly get off the bumper and count how many times the body bounces. It should go up and down ONCE and then slowly return to its position. If it continues to bounce then the shocks/springs are bad and should be replaced. Do this to both the front and rear shocks.