Adjustable positive voltage sag circuitry and adjustable ground bounce circuitry are provided for testing portions of integrated circuits. Adjustable positive voltage sag circuitry and adjustable ground bounce circuitry may provide positive power supply voltages with periodic sags and ground power supply voltages with periodic bounces to test a circuit under test. This may mimic a situation in which a circuit under test is surrounded by devices that switch simultaneously and consume power. Adjustable positive voltage sag circuitry and adjustable ground bounce circuitry allow for a circuit under test to be tested for robustness under such non-ideal power supply conditions.