test_uppercase_response() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call.py lines 299–319

    def test_uppercase_response(self) -> None:
        """Test middleware that transforms response to uppercase."""

        class UppercaseMiddleware(AgentMiddleware):
            def wrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], ModelResponse],
            ) -> ModelCallResult:
                result = handler(request)
                # result is ModelResponse, extract AIMessage from it
                ai_message = result.result[0]
                assert isinstance(ai_message.content, str)
                return AIMessage(content=ai_message.content.upper())

        model = GenericFakeChatModel(messages=iter([AIMessage(content="hello world")]))
        agent = create_agent(model=model, middleware=[UppercaseMiddleware()])

        result = agent.invoke({"messages": [HumanMessage("Test")]})

        assert result["messages"][1].content == "HELLO WORLD"