public void testIndexOf2() {
        YIntervalSeries s1 = new YIntervalSeries("Series 1", false, true);
        s1.add(1.0, 1.0, 1.0, 2.0);
        s1.add(3.0, 3.0, 3.0, 3.0);
        s1.add(2.0, 2.0, 2.0, 2.0);
        assertEquals(0, s1.indexOf(new Double(1.0)));        
        assertEquals(1, s1.indexOf(new Double(3.0)));        
        assertEquals(2, s1.indexOf(new Double(2.0)));