frames = json.loads((folder.parent / 'stream-frames-1.json').read_text())
check('真实流中保存了至少一个文本分片', any((row.get('choices') or [{}])[0].get('delta', {}).get('content') for row in frames))
fixture_text = ''.join((row.get('choices') or [{}])[0].get('delta', {}).get('content', '') for row in data['stream_fixture'])
check('缺usage的反例保留文本且不补成0', fixture_text == '你好' and data['stream_fixture'][-1]['usage'] is None)
result = {'live_text': output['text'], 'live_usage': receipt.get('usage') or None, 'fixture_usage': None, 'fixture_usage_status': 'unknown'}
