@Test
public void testSimpleHash() {

  // Just a simple sanity check.
  final Rectangle2 rect1 = new Rectangle2(1, 2, 0, 0);
  final Rectangle2 rect2 = new Rectangle2(1, 2, 0, 0);
  final Rectangle2 rect3 = new Rectangle2(2, 2, 0, 0);
  assertTrue(rect1.hashCode() == rect2.hashCode());
  assertTrue(rect1.hashCode() != rect3.hashCode());
}