Indicator TFs other then 0 does not work in the Tester ?

If I run this super simple indicator code in the Tester at M15 it works, but it does not work at M5 or M30.

It works in a static indicator(dropped on a chart) but not in the Tester.... is this because we'd be looking into the future ?

//+------------------------------------------------------------------+
int start()
   {
      Comment("stat :",iRSI(Symbol(), 15, 2, 6, 0));    
      return(0);
   }
//+------------------------------------------------------------------+