assertions.py 文件源码

def expect_warnings(*messages, **kw):
    """Context manager which expects one or more warnings.

    With no arguments, squelches all SAWarnings emitted via
    sqlalchemy.util.warn and sqlalchemy.util.warn_limited.   Otherwise
    pass string expressions that will match selected warnings via regex;
    all non-matching warnings are sent through.

    The expect version **asserts** that the warnings were in fact seen.

    Note that the test suite sets SAWarning warnings to raise exceptions.

    """
    return _expect_warnings(sa_exc.SAWarning, messages, **kw)