def METHOD_NAME(self):
    """Integrate zeros except for gravity."""
    test = self.init_algo_class()
    idiot_data = pd.DataFrame(np.zeros((15, 6)), columns=SF_COLS)
    idiot_data["acc_z"] = 9.81
    test = test.estimate(idiot_data, sampling_rate_hz=100)
    expected = np.zeros((16, 3))
    expected_vel = pd.DataFrame(expected, columns=GF_VEL)
    expected_vel.index.name = "sample"
    expected_pos = pd.DataFrame(expected, columns=GF_POS)
    expected_pos.index.name = "sample"
    orientations = np.repeat(test.initial_orientation[None, :], 16, axis=0)
    expected_ori = pd.DataFrame(orientations, columns=GF_ORI)
    expected_ori["q_w"] = 1.0
    expected_ori.index.name = "sample"
    assert_frame_equal(test.position_, expected_pos)
    assert_frame_equal(test.velocity_, expected_vel)
    assert_frame_equal(test.orientation_, expected_ori)