A method and a device for testing for the presence of micro-holes or microcracks in a bottom surface of test objects includes an upper electrode arranged above a transport level and a lower electrode arranged below the transport level. The magnitude of a test voltage generated by two voltage sources connected in series is controlled at the electrodes so that the test voltage is greater than or equal to the breakdown voltage between the electrodes in air, and smaller than the breakdown voltage through a test object without holes or cracks. The test voltage is controlled temporally and synchronously with the movement of the test objects, so that the test voltage is only applied when one of the test objects is located between the electrodes. A hole or crack is recognized by a breakdown to the discharge path between the electrodes.