FakeChatModel Class — langchain Architecture

Architecture documentation for the FakeChatModel class in fake_chat_model.py from the langchain codebase.

Class python

Entity Profile

Dependency Diagram

graph TD
  c74d0ecf_3090_f22c_8651_7b95b58a1752["FakeChatModel"]
  5b9996e6_7ab9_dd69_e0b9_1377111fecae["SimpleChatModel"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|extends| 5b9996e6_7ab9_dd69_e0b9_1377111fecae
  77857b76_cfce_ac63_aef3_e6eb8047bdc2["fake_chat_model.py"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|defined in| 77857b76_cfce_ac63_aef3_e6eb8047bdc2
  76fca993_3750_2bed_ba2e_4a670be1047b["_call()"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|method| 76fca993_3750_2bed_ba2e_4a670be1047b
  6a6b53ec_aa23_914e_695f_e158e3c856aa["_agenerate()"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|method| 6a6b53ec_aa23_914e_695f_e158e3c856aa
  5fe19d53_9716_a7be_7321_61ad1c8ed0ae["_llm_type()"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|method| 5fe19d53_9716_a7be_7321_61ad1c8ed0ae
  effaac33_3d23_887c_804a_8fb87151a819["_identifying_params()"]
  c74d0ecf_3090_f22c_8651_7b95b58a1752 -->|method| effaac33_3d23_887c_804a_8fb87151a819

Relationship Graph

Source Code

libs/langchain/tests/unit_tests/llms/fake_chat_model.py lines 22–54

class FakeChatModel(SimpleChatModel):
    """Fake Chat Model wrapper for testing purposes."""

    @override
    def _call(
        self,
        messages: list[BaseMessage],
        stop: list[str] | None = None,
        run_manager: CallbackManagerForLLMRun | None = None,
        **kwargs: Any,
    ) -> str:
        return "fake response"

    @override
    async def _agenerate(
        self,
        messages: list[BaseMessage],
        stop: list[str] | None = None,
        run_manager: AsyncCallbackManagerForLLMRun | None = None,
        **kwargs: Any,
    ) -> ChatResult:
        output_str = "fake response"
        message = AIMessage(content=output_str)
        generation = ChatGeneration(message=message)
        return ChatResult(generations=[generation])

    @property
    def _llm_type(self) -> str:
        return "fake-chat-model"

    @property
    def _identifying_params(self) -> dict[str, Any]:
        return {"key": "fake"}