easiest test to do for alternator charge is turn engine on.let it run on idle and turn all your accessories on(headlights,radio,etc,etc)if the battery gauge drops...you know your alternator isnt working right(or dead already).
another tet is turn your engine on,run on idle and disconnect the battery positive line.if the car dies..your alternator just conked out.(it should stay running even without the battery connected.