public void Can_calculate_vector_to_another_point() { CartesianPoint SUT = new CartesianPoint(3, 4, 5); CartesianPoint other = new CartesianPoint(5, 4, 3); GeometricVector result = SUT.VectorTo(other); Assert.AreEqual(2, result.X); Assert.AreEqual(0, result.Y); Assert.AreEqual(-2, result.Z); }