from translation.backends.qwen_mt import QwenMTTranslationBackend

  
  
  class _RecordingRedis:
      def __init__(self):
          self.setex_calls = []
  
      def setex(self, key, ttl, value):
          self.setex_calls.append((key, ttl, value))
  
  
  def test_translate_failure_returns_none_and_skips_cache(monkeypatch):

      translator = QwenMTTranslationBackend(
          capability_name="qwen-mt",
          model="qwen-mt-flash",
          base_url="https://dashscope-us.aliyuncs.com/compatible-mode/v1",
          api_key="dummy-key",
          use_cache=False,
      )

      fake_redis = _RecordingRedis()
      translator.use_cache = True
      translator.redis_client = fake_redis
      translator.cache_prefix = "trans"
      translator.expire_seconds = 60
  
      monkeypatch.setattr(translator, "_translate_qwen", lambda *args, **kwargs: None)
  
      result = translator.translate(
          text="商品标题",
          target_lang="en",
          source_lang="zh",

          scene="sku_name",

      )
  
      assert result is None
      assert fake_redis.setex_calls == []