from __future__ import annotations

from pathlib import Path

from alembic.config import Config
from alembic.script import ScriptDirectory


def test_migration_graph_has_unique_revisions_and_one_head() -> None:
    migrations = Path(__file__).parents[1] / "packages" / "harness" / "deerflow" / "persistence" / "migrations"
    config = Config()
    config.set_main_option("script_location", str(migrations))
    scripts = ScriptDirectory.from_config(config)

    revisions = list(scripts.walk_revisions())
    assert len({revision.revision for revision in revisions}) == len(revisions)
    assert len(scripts.get_heads()) == 1