import pytest
import sys
import os

# Robust import in case pytest runs with a constrained PYTHONPATH
try:
    from deltaforge_mvp.demo import main
except Exception:
    # Fallback: load module directly from repo path
    import importlib.util
    import pathlib
    repo_root = pathlib.Path(__file__).parents[1].resolve()
    # Ensure repo root is on sys.path for dynamic import fallback
    if str(repo_root) not in sys.path:
        sys.path.insert(0, str(repo_root))
    demo_path = repo_root / 'deltaforge_mvp' / 'demo.py'
    spec = importlib.util.spec_from_file_location("deltaforge_mvp.demo", str(demo_path))
    if spec is None or spec.loader is None:
        raise ImportError("Could not load deltaforge_mvp.demo fallback module")
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)  # type: ignore
    main = mod.main


def test_demo_runs():
    # Ensure the demo runs without raising
    ret = main()
    assert ret == 0