A seal testing apparatus includes a clamp assembly which receives, secures and rotates a piston and seal assembly, a mandrel which extends into the seal assembly and supports a guide which carries a spring biased sensing probe or tooth which is oriented along the axis of the mandrel. In another embodiment, the components are the similar except that the probe or tooth is disposed in the mandrel and extends circumferentially. In both embodiments, data from an optical, laser or acoustic sensor is analyzed to determine the integrity of the piston seal. Yet another embodiment includes an arbor which rotates the seal and an adjacent contra-rotating cylinder having a conical mirror. As the seal, arbor and cylinder rotate, light reflected off the mirror and the seal, and returned to the mirror and a sensor provide data which is again analyzed to determine the integrity of the piston seal.