test_override_with_copy_pattern() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_overrides.py lines 355–385

    def test_override_with_copy_pattern(self) -> None:
        """Test common pattern of copying and modifying tool_call."""

        @tool
        def test_tool(value: int) -> str:
            """A test tool."""
            return f"Result: {value}"

        original_call = ToolCall(
            name="test_tool",
            args={"value": 5},
            id="call_123",
            type="tool_call",
        )

        original_request = ToolCallRequest(
            tool_call=original_call,
            tool=test_tool,
            state=AgentState(messages=[]),
            runtime=Mock(),
        )

        # Common pattern: copy tool_call and modify args
        modified_call = ToolCall({**original_request.tool_call, "args": {"value": 10}})
        new_request = original_request.override(tool_call=modified_call)

        assert new_request.tool_call["args"]["value"] == 10
        assert new_request.tool_call["id"] == "call_123"
        assert new_request.tool_call["name"] == "test_tool"
        # Original unchanged
        assert original_request.tool_call["args"]["value"] == 5