assertions.py 文件源码

def expect_warnings(*messages):
    """Context manager to expect warnings with the given messages."""

    filters = [dict(action='ignore',
                    category=sa_exc.SAPendingDeprecationWarning)]
    if not messages:
        filters.append(dict(action='ignore',
                            category=sa_exc.SAWarning))
    else:
        filters.extend(dict(action='ignore',
                            message=message,
                            category=sa_exc.SAWarning)
                       for message in messages)
    for f in filters:
        warnings.filterwarnings(**f)
    try:
        yield
    finally:
        resetwarnings()