"""Run the shipped demo end-to-end as a subprocess.

The demo (demo/run_demo.py) walks one amendment through ratification and
shows another being blocked by the vote gate. It is the canonical
integration test of the whole pipeline: if it exits non-zero, the
milestone's headline claim is broken.
"""

from __future__ import annotations

from tests.helpers import PROJECT_ROOT, run_script


def test_demo_runs_clean():
    result = run_script(PROJECT_ROOT / "demo" / "run_demo.py", cwd=PROJECT_ROOT)
    assert result.returncode == 0, (
        f"demo exited {result.returncode}\n--- stdout ---\n{result.stdout}\n"
        f"--- stderr ---\n{result.stderr}"
    )
    assert result.stdout.strip(), "the demo should narrate what it is doing"


def test_demo_is_idempotent():
    """Running the demo twice must not corrupt anything or fail the second time."""
    first = run_script(PROJECT_ROOT / "demo" / "run_demo.py", cwd=PROJECT_ROOT)
    second = run_script(PROJECT_ROOT / "demo" / "run_demo.py", cwd=PROJECT_ROOT)
    assert first.returncode == 0, first.stderr
    assert second.returncode == 0, second.stderr