"""Self-check for the per-statement startup DDL guard (main._ensure_tables).
Proves the real guarantee: ONE failing statement is isolated — every other statement is still
attempted and the app boots. No live DB (fake engine). Run: .venv/bin/python test_startup_ddl.py"""
import asyncio
import app.main as m


class _FakeConn:
    def __init__(self, boom):
        self.boom, self.seen = boom, []

    async def execute(self, stmt):
        s = str(stmt)
        self.seen.append(s)
        if self.boom in s:
            raise RuntimeError("simulated DDL failure")


class _FakeBegin:
    def __init__(self, conn):
        self.conn = conn

    async def __aenter__(self):
        return self.conn

    async def __aexit__(self, *a):
        return False        # don't swallow — the loop's own try/except must handle it


class _FakeEngine:
    def __init__(self, conn):
        self.conn = conn

    def begin(self):
        return _FakeBegin(self.conn)


def test_isolation():
    boom = "CREATE EXTENSION IF NOT EXISTS pg_trgm"   # a real statement in the list
    conn = _FakeConn(boom)
    orig = m.engine
    m.engine = _FakeEngine(conn)
    try:
        asyncio.run(m._ensure_tables())               # must NOT raise
    finally:
        m.engine = orig
    assert any(boom in s for s in conn.seen), "the boom statement was never reached"
    assert len(conn.seen) == len(m._STARTUP_DDL), \
        f"only {len(conn.seen)}/{len(m._STARTUP_DDL)} attempted — a failure aborted the batch"
    print(f"ok — all {len(conn.seen)} statements attempted; the failing one was isolated")


if __name__ == "__main__":
    test_isolation()