To initiate and get the status of the cable test feature. It
is applicable only to copper ports. In the future we may
have multiple copper ports. A GET on this object will show
testIdle if a test has never been run, or testCompleted(4)
if it has.
When testStart(2) is SET, for a short time of
about 3 seconds you would expect to see testInProgress(3).
Time-stamp of the test start will be sent by the SNMP agent
to the line-card to keep track of the time instance of the
test.