A method for testing a circuit comprising a memory element, a voltage comparator and a supply selector, the circuit is configured to be connected to two power supplies, the voltage comparator is configured to provide an output indicative of a voltage difference between the two power supplies above a predetermined threshold, the supply selector is configured to select a power supply to feed power to the memory element in response to the output from the voltage comparator. The method comprises connecting the two power supplies to the circuit, wherein said connecting comprises causing the two power supplies to drive power to the memory element and to another element of the circuit, wherein the voltage different between the two power supplies is above the predetermined threshold. The method further comprises that in response to said connecting, the supply selector of the circuit is invoked and disconnects one power supply from the memory element; whereby stress testing the circuit, the stress testing tests the memory element without a voltage difference condition, the stress testing tests the another element with the voltage difference condition.