public void test_Protocol_value() {
   // a regular one
   assertEquals(KEYRecord.Protocol.IPSEC, KEYRecord.Protocol.value("IPSEC"));
   // a unassigned value within range
   assertEquals(254, KEYRecord.Protocol.value("254"));
   // too low
   assertEquals(-1, KEYRecord.Protocol.value("-2"));
   // too high
   assertEquals(-1, KEYRecord.Protocol.value("256"));
 }