def test_prepare_function_call_invalid_return_type():
    """Test function preparation with invalid return type (non-Pydantic)"""
    def test_func(text: str) -> str:
        """Process this: {{ text }}"""
        pass

    with pytest.raises(AssertionError):
        _prepare_function_call(
            test_func,
            args=("Hello",),
            kwargs={}
        )
Test function preparation with invalid return type (non-Pydantic)
tests/test_function_prep.py