from __future__ import annotations

import ast
import unittest
from pathlib import Path


INIT_PATH = Path(__file__).resolve().parents[1] / "trellis" / "models" / "__init__.py"


def _from_pretrained_function() -> ast.FunctionDef:
    tree = ast.parse(INIT_PATH.read_text(encoding="utf-8"))
    for node in tree.body:
        if isinstance(node, ast.FunctionDef) and node.name == "from_pretrained":
            return node
    raise AssertionError("from_pretrained not found")


class TrellisFromPretrainedCpuLoadTests(unittest.TestCase):
    def test_from_pretrained_avoids_cuda_probe_and_loads_pt_on_cpu(self) -> None:
        fn = _from_pretrained_function()
        source_segment = ast.get_source_segment(INIT_PATH.read_text(encoding="utf-8"), fn)
        assert source_segment is not None

        self.assertNotIn("torch.cuda.is_available", source_segment)
        self.assertIn('map_location="cpu"', source_segment)


if __name__ == "__main__":
    unittest.main()