An apparatus and method are provided for testing integrated circuits. An integrated circuit arrangement is provided having first and second dice. Each die has circuitry for diagnostic testing in response to a diagnostic test signal. The circuitry further defines an input for receiving the diagnostic test signal and an output for transmitting results of the diagnostic testing for each of the dice. Interconnecting circuitry between the dice transmits the diagnostic test signal transmitted to the first die to the second die before the diagnostic testing is completed in the first die.