test_async_none_tools_emulates_all() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_emulator.py lines 519–549

    async def test_async_none_tools_emulates_all(self) -> None:
        """Test that None tools means ALL tools are emulated in async mode."""
        agent_model = FakeModel(
            messages=cycle(
                [
                    AIMessage(
                        content="",
                        tool_calls=[
                            {"name": "get_weather", "id": "1", "args": {"location": "NYC"}}
                        ],
                    ),
                    AIMessage(content="Done."),
                ]
            )
        )

        emulator_model = FakeEmulatorModel(responses=["Emulated: 65°F in NYC"])

        # tools=None means emulate ALL tools
        emulator = LLMToolEmulator(tools=None, model=emulator_model)

        agent = create_agent(
            model=agent_model,
            tools=[get_weather],
            middleware=[emulator],
        )

        result = await agent.ainvoke({"messages": [HumanMessage("What's the weather in NYC?")]})

        # Should complete without raising NotImplementedError
        assert isinstance(result["messages"][-1], AIMessage)