### Question:
GeneralFunction extends Function implements GsonObject { public abstract Datum eval(Tuple params); GeneralFunction(Column[] definedArgs); void init(FunctionEval.ParamType [] paramTypes); abstract Datum eval(Tuple params); @Override String toJson(); @Override CatalogProtos.FunctionType getFunctionType();  }### Answer:
@Test public void testDate() { Date date = new Date(); Tuple tuple = new VTuple(new Datum[] {new TextDatum("25/12/2012 00:00:00")}); Int8Datum unixtime = (Int8Datum) date.eval(tuple); Calendar c = Calendar.getInstance(); c.setTimeInMillis(unixtime.asInt8()); assertEquals(2012, c.get(Calendar.YEAR)); assertEquals(11, c.get(Calendar.MONTH)); assertEquals(25, c.get(Calendar.DAY_OF_MONTH)); assertEquals(0, c.get(Calendar.HOUR_OF_DAY)); assertEquals(0, c.get(Calendar.MINUTE)); assertEquals(0, c.get(Calendar.SECOND)); }