Bug 201017 TopN, TopPercent, BottomPercent filters will lead NPE when the values contains NULL[07]
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/aggregation/TotalTest.java
ac.start();
        for(int i=0; i<doubleArray3.length; i++)
        {
            ac.onRow(new Object[]{doubleArray3[i], new Double(2)});
        }
        ac.finish();
        value = ac.getValue( );
        assertEquals(value, new Double( 30 ));
        
        ac.start();
        for(int i=0; i<doubleArray3.length; i++)
        {
            ac.onRow(new Object[]{doubleArray3[i], new Double(3)});
        }
        ac.finish();
        value = ac.getValue( );
        assertEquals(value, new Double( 85 ));
        
        ac.start();
        for(int i=0; i<doubleArray3.length; i++)
        {
            ac.onRow(new Object[]{doubleArray3[i], new Double(4)});
        }
        ac.finish();
        value = ac.getValue( );
        assertEquals(value, new Double( 300 ));
        
        try{
       	 ac.start();