public void TestNonOverlappingLines(double x1s, double y1s, double x1e, double y1e, double x2s, double y2s, double x2e, double y2e)
{
Point2D l1s = new Point2D(x1s, y1s);
Point2D l1e = new Point2D(x1e, y1e);
Point2D l2s = new Point2D(x2s, y2s);
Point2D l2e = new Point2D(x2e, y2e);
LineSegment2D l1 = new LineSegment2D(l1s, l1e);
LineSegment2D l2 = new LineSegment2D(l2s, l2e);
var intersection = l1.AreIntersecting(l1.P1, l1.P2, l2.P1, l2.P2);
Assert.False(intersection);
var res = l1.CalculateIntersection(l2);
Assert.Null(res);
}