When I did mine (probably just less than a year ago) the medical examiner just told me to face the other way. He then asked me to cover each ear in turn and repeat some numbers he read out.
It was certainly not a test of 'good hearing' but to confirm you were hearing what he said and not guessing or lipreading.
It was really basic. If you fail then you would probably have to be referred to get hearing aids or similar.