def METHOD_NAME():
    # test vectorized input, all together
    query = np.stack([
        [FITTER.x0 + R_SPHERE, FITTER.y0, FITTER.z0],
        [FITTER.x0, FITTER.y0 + R_SPHERE, FITTER.z0],
        # [FITTER.x0, FITTER.y0, FITTER.z0 + R_SPHERE],
        [FITTER.x0, FITTER.y0 + R_SPHERE, FITTER.z0 + R_SPHERE]
    ])
    normals = FITTER.approximate_normal(query[:, 0], query[:, 1], query[:, 2])
    true_normals = np.stack([
        [1, 0, 0],
        [0, 1, 0],
        # [0, 0, 1],
        [0, 1./np.sqrt(2), 1./np.sqrt(2)]
    ])
    np.testing.assert_almost_equal(normals, true_normals, decimal=3)