"""Shared test fixtures.

`db_conn` yields a psycopg connection inside a transaction that is rolled back
after each test, so DB tests stay isolated and leave no residue. Tests are
skipped automatically when no database is reachable or M4 migrations are not
applied (e.g. local runs without docker).
"""

from __future__ import annotations

import psycopg
import pytest

from opengoods.etl.load import default_dsn


@pytest.fixture()
def db_conn():
    try:
        conn = psycopg.connect(default_dsn(), connect_timeout=3)
    except psycopg.OperationalError as exc:  # pragma: no cover - env dependent
        pytest.skip(f"no database available: {exc}")
    has_state = conn.execute("SELECT to_regclass('public.ingest_state') IS NOT NULL").fetchone()[0]
    if not has_state:
        conn.close()
        pytest.skip("M4 migrations not applied")
    try:
        yield conn
    finally:
        conn.rollback()
        conn.close()