d.add(1, 2);
assertEquals(1, d.getPointCount());
assertEquals(1, points.size());
assertEquals(new Point2D.Double(2, 1), points.get(0));
DoubleData xData = new DoubleDataDouble();
DoubleData yData = new DoubleDataDouble();
xData.add(2);
yData.add(3);
xData.add(3);
yData.add(4);
d.prepend(xData, yData);
assertEquals(3, d.getPointCount());
assertEquals(3, points.size());
assertEquals(new Point2D.Double(4, 3), points.get(0));
assertEquals(new Point2D.Double(3, 2), points.get(1));