def METHOD_NAME(self):
    """
    Test automatic generation of face normals on mesh objects
    """
    mesh = g.trimesh.creation.icosahedron()
    assert mesh.face_normals.shape == mesh.faces.shape
    # normals should regenerate
    mesh.face_normals = None
    assert mesh.face_normals.shape == mesh.faces.shape
    # we shouldn't be able to assign stupid wrong values
    # even with nonzero and the right shape
    mesh.face_normals = g.np.ones_like(mesh.faces) * [0.0, 0.0, 1.0]
    assert not g.np.allclose(mesh.face_normals, [0.0, 0.0, 1.0])
    # setting normals to None should force recompute
    mesh.face_normals = None
    assert mesh.face_normals is not None
    assert not g.np.allclose(mesh.face_normals,
                             [0.0, 0.0, 1.0])
    # setting face normals to zeros shouldn't work
    mesh.face_normals = g.np.zeros_like(mesh.faces)
    assert g.np.allclose(
        g.np.linalg.norm(mesh.face_normals, axis=1), 1.0)