9v battery across terminals will tell you they work, the gently push the cone down to see if you can feel the coil rubbing. If it does it’s toast. Smell for burning
As Parm says, also measure resistance with a multimeter (should be about 3 Ohms). Check for rubbing. Tap cone with your finger. should sound clean, not vibrating/rattly. Inspect for cone or spider coming unglued.