As long as it's not an initial medical test just be laid back about it. If you fail the test completely and utterly, the rulebook sayeth that you get a practical check with a training captain, and as long as you CAN actually hear the radio, the idents, the intercom etc, then you will be OK. Maybe catch an 'as or with' rating, but that's not critical for most operations these days, precious little single crew stuff around.
Good luck!
