@Test
public void testDistance() {

  final Vector2 vec1 = new Vector2(0, 0);
  assertTrue(3.0 == vec1.distance(0, 3));
  assertTrue(4.0 == vec1.distance(4, 0));
  final Vector2 vec2 = new Vector2(1, 1);
  assertTrue(Math.sqrt(2) == vec1.distance(vec2));
}