Test handler including gripper-type test contactor

A test handler is provided for testing electronic devices having light-emitting elements. Electronic devices are mounted at a loading position, optical measurements are conducted at a test contact position where a testing device is located for optical communication with the light-emitting elements and then tested electronic devices are removed at an unloading position. Multiple test contactors hold the electronic devices and move them to and through the loading position, test contact position and unloading position in sequence. Each test contactor comprises a device contact point including electrical conductors which are connected to electrical contacts of the electronic device when the electronic device is mounted at the device contact point, and a retaining mechanism grips the electronic device at the device contact point such that the retaining mechanism does not obstruct the optical communication between the testing device and the light-emitting element at the test contact position.