test_override_preserves_identity_of_unchanged_objects() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_overrides.py lines 151–174

    def test_override_preserves_identity_of_unchanged_objects(self) -> None:
        """Test that unchanged attributes maintain object identity."""
        model = GenericFakeChatModel(messages=iter([AIMessage(content="Hello")]))
        messages: list[AnyMessage] = [HumanMessage("Hi")]

        state = AgentState[Any](messages=[])

        original_request = ModelRequest(
            model=model,
            system_message=SystemMessage("Original prompt"),
            messages=messages,
            tool_choice=None,
            tools=[],
            response_format=None,
            state=state,
            runtime=None,
        )

        new_request = original_request.override(system_message=SystemMessage("New prompt"))

        # Unchanged objects should be the same instance
        assert new_request.messages is messages
        assert new_request.state is state
        assert new_request.model is model