public void testNotification() {
        CombinedRangeXYPlot plot = createPlot();
        JFreeChart chart = new JFreeChart(plot);
        chart.addChangeListener(this);
        XYPlot subplot1 = (XYPlot) plot.getSubplots().get(0);
        NumberAxis xAxis = (NumberAxis) subplot1.getDomainAxis();
        xAxis.setAutoRangeIncludesZero(!xAxis.getAutoRangeIncludesZero());
        assertEquals(1, this.events.size());
        
        // a redraw should NOT trigger another change event
        BufferedImage image = new BufferedImage(200, 100, 
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = image.createGraphics();
        this.events.clear();
        chart.draw(g2, new Rectangle2D.Double(0.0, 0.0, 200.0, 100.0));
        assertTrue(this.events.isEmpty());
    }
    
    /**
     * Creates a sample dataset.
     *
     * @return Series 1.
     */
    private XYDataset createDataset1() {

        XYSeries series1 = new XYSeries("Series 1");
        series1.add(10.0, 12353.3);
        series1.add(20.0, 13734.4);
        series1.add(30.0, 14525.3);
        series1.add(40.0, 13984.3);
        series1.add(50.0, 12999.4);
        series1.add(60.0, 14274.3);
        series1.add(70.0, 15943.5);
        series1.add(80.0, 14845.3);
        series1.add(90.0, 14645.4);
        series1.add(100.0, 16234.6);
        series1.add(110.0, 17232.3);
        series1.add(120.0, 14232.2);
        series1.add(130.0, 13102.2);
        series1.add(140.0, 14230.2);
        series1.add(150.0, 11235.2);

        XYSeries series2 = new XYSeries("Series 2");
        series2.add(10.0, 15000.3);
        series2.add(20.0, 11000.4);
        series2.add(30.0, 17000.3);
        series2.add(40.0, 15000.3);
        series2.add(50.0, 14000.4);
        series2.add(60.0, 12000.3);
        series2.add(70.0, 11000.5);
        series2.add(80.0, 12000.3);
        series2.add(90.0, 13000.4);
        series2.add(100.0, 12000.6);
        series2.add(110.0, 13000.3);
        series2.add(120.0, 17000.2);
        series2.add(130.0, 18000.2);
        series2.add(140.0, 16000.2);
        series2.add(150.0, 17000.2);

        XYSeriesCollection collection = new XYSeriesCollection();
        collection.addSeries(series1);
        collection.addSeries(series2);
        return collection;

    }

    /**
     * Creates a sample dataset.
     *
     * @return Series 2.
     */
    private XYDataset createDataset2() {

        // create dataset 2...
        XYSeries series2 = new XYSeries("Series 3");

        series2.add(10.0, 16853.2);
        series2.add(20.0, 19642.3);
        series2.add(30.0, 18253.5);
        series2.add(40.0, 15352.3);
        series2.add(50.0, 13532.0);
        series2.add(100.0, 12635.3);
        series2.add(110.0, 13998.2);
        series2.add(120.0, 11943.2);
        series2.add(130.0, 16943.9);
        series2.add(140.0, 17843.2);
        series2.add(150.0, 16495.3);
        series2.add(160.0, 17943.6);
        series2.add(170.0, 18500.7);
        series2.add(180.0, 19595.9);

        return new XYSeriesCollection(series2);