assertions.py 文件源码

def emits_warning(*messages):
    """Mark a test as emitting a warning.

    With no arguments, squelches all SAWarning failures.  Or pass one or more
    strings; these will be matched to the root of the warning description by
    warnings.filterwarnings().
    """
    # TODO: it would be nice to assert that a named warning was
    # emitted. should work with some monkeypatching of warnings,
    # and may work on non-CPython if they keep to the spirit of
    # warnings.showwarning's docstring.
    # - update: jython looks ok, it uses cpython's module

    @decorator
    def decorate(fn, *args, **kw):
        # todo: should probably be strict about this, too
        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:
            return fn(*args, **kw)
        finally:
            resetwarnings()
    return decorate