def METHOD_NAME(self, axis_out_shape):
    axis, out_shape = axis_out_shape
    expected_exc = ValueError
    out_np = np.empty(out_shape)
    out_num = num.empty(out_shape)
    with pytest.raises(expected_exc):
        np.mean(self.arr_np, axis=axis, out=out_np)
    with pytest.raises(expected_exc):
        num.mean(self.arr_num, axis=axis, out=out_num)