"""mattermost-lts — UPGRADE overlay (Phase 1e HC3): data-continuity, assertion-only + additive.
ops.pre_upgrade wrote a postgres marker row before the upgrade; this overlay ADDS: the postgres data
survived the chaos crossover. Read via psql in the `db` service."""

import os
import sys

sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner"))
from harness import lifecycle  # noqa: E402


def _psql(domain, sql):
    cmd = (
        "PGPASSWORD=$(cat /run/secrets/postgres_password) "
        f'psql -U mattermost -d mattermost -tAc "{sql}"'
    )
    return lifecycle.exec_in_app(domain, ["sh", "-c", cmd], service="postgres").strip()


def test_upgrade_preserves_data(live_app):
    assert _psql(live_app, "SELECT v FROM ci_marker;") == "upgrade-survives", (
        "postgres data did not survive the upgrade"
    )
