public void testIndexOf() {
        YIntervalSeries s1 = new YIntervalSeries("Series 1");
        s1.add(1.0, 1.0, 1.0, 2.0);
        s1.add(2.0, 2.0, 2.0, 3.0);
        s1.add(3.0, 3.0, 3.0, 4.0);
        assertEquals(0, s1.indexOf(new Double(1.0)));
    }
    
    /**
     * A check for the indexOf() method for an unsorted series.
     */
    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)));        
    }

    /**
     * Simple test for the remove() method.
     */
    public void testRemove() {
        YIntervalSeries s1 = new YIntervalSeries("Series 1");
        s1.add(1.0, 1.0, 1.0, 2.0);
        s1.add(2.0, 2.0, 2.0, 2.0);
        s1.add(3.0, 3.0, 3.0, 3.0);
        assertEquals(3, s1.getItemCount());
        
        s1.remove(new Double(2.0));
        assertEquals(new Double(3.0), s1.getX(1));
        
        s1.remove(new Double(1.0));
        assertEquals(new Double(3.0), s1.getX(0));    
    }

    private static final double EPSILON = 0.0000000001;
    
    /**
     * When items are added with duplicate x-values, we expect them to remain 
     * in the order they were added.
     */
    public void testAdditionOfDuplicateXValues() {
        YIntervalSeries s1 = new YIntervalSeries("Series 1");
        s1.add(1.0, 1.0, 1.0, 1.0);
        s1.add(2.0, 2.0, 2.0, 2.0);
        s1.add(2.0, 3.0, 3.0, 3.0);
        s1.add(2.0, 4.0, 4.0, 4.0);
        s1.add(3.0, 5.0, 5.0, 5.0);
        assertEquals(1.0, s1.getYValue(0), EPSILON);
        assertEquals(2.0, s1.getYValue(1), EPSILON);
        assertEquals(3.0, s1.getYValue(2), EPSILON);
        assertEquals(4.0, s1.getYValue(3), EPSILON);
        assertEquals(5.0, s1.getYValue(4), EPSILON);
    }
    
    /**
     * Some checks for the add() method for an UNSORTED series.
     */
    public void testAdd() {
        YIntervalSeries series = new YIntervalSeries("Series", false, true);
        series.add(5.0, 5.50, 5.50, 5.50);
        series.add(5.1, 5.51, 5.51, 5.51);
        series.add(6.0, 6.6, 6.6, 6.6);
        series.add(3.0, 3.3, 3.3, 3.3);
        series.add(4.0, 4.4, 4.4, 4.4);
        series.add(2.0, 2.2, 2.2, 2.2);
        series.add(1.0, 1.1, 1.1, 1.1);
        assertEquals(5.5, series.getYValue(0), EPSILON);
        assertEquals(5.51, series.getYValue(1), EPSILON);
        assertEquals(6.6, series.getYValue(2), EPSILON);
        assertEquals(3.3, series.getYValue(3), EPSILON);
        assertEquals(4.4, series.getYValue(4), EPSILON);
        assertEquals(2.2, series.getYValue(5), EPSILON);
        assertEquals(1.1, series.getYValue(6), EPSILON);
    }
    
    /**
     * A simple check that the maximumItemCount attribute is working.
     */
    public void testSetMaximumItemCount() {
        YIntervalSeries s1 = new YIntervalSeries("S1");
        assertEquals(Integer.MAX_VALUE, s1.getMaximumItemCount());
        s1.setMaximumItemCount(2);
        assertEquals(2, s1.getMaximumItemCount());
        s1.add(1.0, 1.1, 1.1, 1.1);
        s1.add(2.0, 2.2, 2.2, 2.2);
        s1.add(3.0, 3.3, 3.3, 3.3);
        assertEquals(2.0, s1.getX(0).doubleValue(), EPSILON);
        assertEquals(3.0, s1.getX(1).doubleValue(), EPSILON);
    }
    
    /**
     * Check that the maximum item count can be applied retrospectively.
     */
    public void testSetMaximumItemCount2() {
        YIntervalSeries s1 = new YIntervalSeries("S1");
        s1.add(1.0, 1.1, 1.1, 1.1);
        s1.add(2.0, 2.2, 2.2, 2.2);
        s1.add(3.0, 3.3, 3.3, 3.3);
        s1.setMaximumItemCount(2);
        assertEquals(2.0, s1.getX(0).doubleValue(), EPSILON);
        assertEquals(3.0, s1.getX(1).doubleValue(), EPSILON);
    }
    
    /**
     * Some checks for the clear() method.
     */
    public void testClear() {
        YIntervalSeries s1 = new YIntervalSeries("S1");
        s1.addChangeListener(this);
        s1.clear();
        assertNull(this.lastEvent);
        assertTrue(s1.isEmpty());
        s1.add(1.0, 2.0, 3.0, 4.0);
        assertFalse(s1.isEmpty());
        s1.clear();
        assertNotNull(this.lastEvent);
        assertTrue(s1.isEmpty());