def METHOD_NAME(self):
    trackball = Trackball(
        pose=g.np.eye(4),
        size=(640, 480),
        scale=1.0,
        target=g.np.array([0, 0, 0])
    )
    # translate to x
    trackball.set_state(Trackball.STATE_PAN)
    trackball.down((321, 241))
    trackball.drag((320, 241))
    g.np.testing.assert_allclose(trackball.pose[:3, :3], g.np.eye(3))
    assert trackball.pose[0, 3] != 0
    assert trackball.pose[1, 3] == 0
    assert trackball.pose[2, 3] == 0