'Assert that no events have passed the filter since `start_time`.'

def assert_no_matching_events_were_emitted(self, event_filter, start_time=None):

    matching_events = self.get_matching_events_from_time(start_time=start_time, event_filter=event_filter)
    description = CollectedEventsDescription(('Events    unexpected    matched    the    filter:\n' + self.event_filter_to_descriptive_string(event_filter)), (lambda : matching_events))
    self.assertEquals(len(matching_events), 0, description)
