An integrated testing apparatus provides bidirectional coupling of a high voltage either from an internal source on an integrated circuit to a first external pin on the integrated circuit package, or to the output point of said internal source of high voltage from a voltage source external to the integrated circuit package that is coupled to said first external pin, said coupling occurring in response to an enabling signal externally impressed on a second external pin on said integrated circuit package. The testing apparatus is substantially transparent to normal integrated circuit operation when said enabling signal is removed from said second external pin.