In a method for testing an electronic device, the method includes: providing an electronic device including a display layer and a sensor layer on the display layer and configured to operate at a touch drive frequency, the sensor layer including a plurality of first electrodes and a plurality of second electrodes insulatively intersecting the plurality of first electrodes; providing a test signal having a test frequency higher than the touch drive frequency to the plurality of first electrodes; measuring mutual capacitance with the plurality of first electrodes through the plurality of second electrodes; and determining whether or not the sensor layer is defective, based on the mutual capacitance.