def METHOD_NAME(self):
    ring1_center = np.array([0.0, 0.0, 0.0])
    ring2_center_true = np.array([4.0, 0.0, 0.0])
    ring2_center_false = np.array([10.0, 0.0, 0.0])
    ring1_normal_true = np.array([1.0, 0.0, 0.0])
    ring1_normal_false = np.array([0.0, 1.0, 0.0])
    for ring2_normal in (np.array([2.0, 0, 0]), np.array([-3.0, 0, 0])):
        # parallel normals
        self.assertTrue(
            is_pi_parallel(ring1_center, ring1_normal_true,
                           ring2_center_true, ring2_normal))
        # perpendicular normals
        self.assertFalse(
            is_pi_parallel(ring1_center, ring1_normal_false,
                           ring2_center_true, ring2_normal))
        # too far away
        self.assertFalse(
            is_pi_parallel(ring1_center, ring1_normal_true,
                           ring2_center_false, ring2_normal))