public static void CrossProduct_3D(
     double x1, double y1, double z1,
     double x2, double y2, double z2,
     double xExpected, double yExpected, double zExpected)
 {
     double[] result = VectorLibrary.CrossProduct3D(x1, y1, z1, x2, y2, z2);
     Assert.AreEqual(xExpected, result[0], Tolerance);
     Assert.AreEqual(yExpected, result[1], Tolerance);
     Assert.AreEqual(zExpected, result[2], Tolerance);
 }