'The same format field used twice in one event is rendered twice.
@param event: An event to flatten.  If L{None}, create a new event.
@return: C{event} or the event created.'

def _test_formatFlatEvent_fieldNamesSame(self, event=None):

    if (event is None):
        counter = count()
        class CountStr(object, ):
            '\n                                                                Hack\n                                                                '
            def __str__(self):
                return str(next(counter))
        event = dict(log_format='{x}    {x}', x=CountStr())
    flattenEvent(event)
    self.assertEqual(formatEvent(event), u'0    1')
    return event
