@Test
public void parallelLines() {

    Tuple2d intersect = VecmathUtil.intersection(new Point2d(0, 1), new Vector2d(0, 1), new Point2d(0, -1),
            new Vector2d(0, 1));
    assertTrue(Double.isNaN(intersect.x));
    assertTrue(Double.isNaN(intersect.y));
}