public void Triangle_Inequality_Holds(Vector3D first, Vector3D second)
 {
     CompareAssert.Assert((first + second).Length).IsLessThanOrEqualTo(first.Length + second.Length);
 }
 public void Vector_Length_Is_Non_Negative(Vector3D vector)
 {
     CompareAssert.Assert(vector.Length).IsGreaterThanOrEqualTo(0);
 }
 public void Vector_Length_Is_At_Least_As_Great_As_Any_Component(Vector3D vector)
 {
     CompareAssert.Assert(vector.Length).IsGreaterThanOrEqualTo(vector.X);
     CompareAssert.Assert(vector.Length).IsGreaterThanOrEqualTo(vector.Y);
     CompareAssert.Assert(vector.Length).IsGreaterThanOrEqualTo(vector.Z);
 }