When the mailing list has its emergency flag set, all messages posted to the list are held for moderator approval.

>>> mlist = create_list('test@example.com')
>>> rule = config.rules['emergency']
>>> msg = message_from_string("""\
... From: aperson@example.com
... To: test@example.com
... Subject: My first post
... Message-ID: <first>
... An important message.
... """)

By default, the mailing list does not have its emergency flag set.

>>> mlist.emergency
>>> rule.check(mlist, msg, {})

The emergency rule matches if the flag is set on the mailing list.

>>> mlist.emergency = True
>>> rule.check(mlist, msg, {})

However, if the message metadata has a moderator_approved key set, then even if the mailing list has its emergency flag set, the message still goes through to the membership.

>>> rule.check(mlist, msg, dict(moderator_approved=True))