'Send an event to a wrapped legacy observer and verify that its data is
preserved.
@param event: an event
@type event: L{dict}
@return: the event as observed by the legacy wrapper'

def forwardAndVerify(self, event):

    event.setdefault('log_time', time())
    event.setdefault('log_system', '-')
    event.setdefault('log_level', LogLevel.info)
    observed = self.observe(dict(event))
    for (key, value) in event.items():
        self.assertIn(key, observed)
    return observed
