NULL_ETHERNET_ADDRESS_BYTE_ARRAY, 0, test_array, 0);
// now test a non-null EthernetAddress
ethernet_address = new EthernetAddress(MIXED_CASE_VALID_ETHERNET_ADDRESS_STRING);
Arrays.fill(test_array, (byte)'x');
ethernet_address.toByteArray(test_array);
assertEthernetAddressArraysAreEqual(
VALID_ETHERNET_ADDRESS_BYTE_ARRAY, 0, test_array, 0);
// now test a null EthernetAddress case with extra data in the array
ethernet_address = new EthernetAddress(0L);