def _overall_output(ts, format_str):
    """Returns a string giving the overall test status

    Args:
    ts: TestStatus object
    format_str (string): string giving the format of the output; must
        contain place-holders for status and test_name
    """
    test_name = ts.get_name()
    status = ts.get_overall_test_status()
    return format_str.format(status=status, test_name=test_name)