def METHOD_NAME(mock_cubes):
    """Test units after derivation if derivation scripts returns None."""
    mock_all_derived_variables(Unit('unknown'))
    cube = derive(mock_cubes, SHORT_NAME, mock.sentinel.long_name, 'J',
                  standard_name=mock.sentinel.standard_name)
    assert_derived_var_calc_called_once_with(mock_cubes)
    assert cube.units == Unit('J')
    assert cube.var_name == SHORT_NAME
    assert cube.long_name == mock.sentinel.long_name
    assert cube.standard_name == mock.sentinel.standard_name
    _derive.logger.warning.assert_called_once_with(
        "Units of cube after executing derivation script of '%s' are '%s', "
        "automatically setting them to '%s'. This might lead to incorrect "
        "data", SHORT_NAME, Unit('unknown'), 'J')
    cube.convert_units.assert_not_called()