def METHOD_NAME(self):
    s = Spline()
    s.add_point(Vector3d(0, 0, 0))
    s.add_point(Vector3d(.4, .4, .4))
    s.add_point(Vector3d(0, 0, 0))
    s.recalc_tangents()
    self.assertAlmostEqual(s.interpolate(0, 0.5), Vector3d(0.2, 0.2, 0.2))
    self.assertAlmostEqual(s.interpolate(1, 0.5), Vector3d(0.2, 0.2, 0.2))