@Test
public void testDistance() {

  final Vector3 vec1 = new Vector3(0, 0, 0);
  assertTrue(4.0 == vec1.distance(4, 0, 0));
  assertTrue(3.0 == vec1.distance(0, 3, 0));
  assertTrue(2.0 == vec1.distance(0, 0, 2));
  final Vector3 vec2 = new Vector3(1, 1, 1);
  assertTrue(Math.sqrt(3) == vec1.distance(vec2));
}