Since flight attendants technically (at least based on what the union is saying) are employed to provide a safe and secure flight to the passengers in case of an emergency -is there a certification or a test that the FA's undertake? I know they get training in procedures, but is there such a thing as a test to ensure that the FA's are fit for the job (is any airline doing this)?

Recently i've been travelling with some FA's that have looked really frail and i've begun to wonder if they really can perform their duties in case of an emergency.

inquiring minds would like to know....