with self._conn.lock:
                self._conn.wait(
                    self._execute_gen(query, params, prepare=prepare, binary=binary)
                )
        except e._NO_TRACEBACK as ex:
>           raise ex.with_traceback(None)
E           sqlalchemy.exc.OperationalError: (psycopg.errors.ObjectInUse) database "bulkmailer_test_8349aeb9" is being accessed by other users
E           DETAIL:  There is 1 other session using the database.
E           [SQL: DROP DATABASE IF EXISTS "bulkmailer_test_8349aeb9"]
E           (Background on this error at: https://sqlalche.me/e/20/e3q8)

/usr/local/lib/python3.11/site-packages/psycopg/cursor.py:97: OperationalError
=================================== FAILURES ===================================
_ TestMaterializeCampaign.test_invoice_numbers_unique_across_materialize_calls _

self = <tests.test_campaign_engine.TestMaterializeCampaign object at 0x7eff19fce810>
db_engine = Engine(postgresql+psycopg://mailer:***@localhost:5432/bulkmailer_test_8349aeb9)

    def test_invoice_numbers_unique_across_materialize_calls(self, db_engine):
        """Same campaign materialized twice (draft re-preview) — the collision set
        is per call, but DB uniqueness per campaign holds because rows are
        regenerated. Verified: two calls with the same recipient set produce
        distinct plans and both unique sets."""
        from sqlalchemy.orm import Session
        with Session(db_engine, expire_on_commit=False) as db:
            f = _seed_fixture(db, n_recipients=8)
            recs = db.query(Recipient).filter_by(list_id=f["campaign"].recipient_list_id).all()
            res1 = _async_materialize(db_engine, f["campaign"], recs, preview=True)
            res2 = _async_materialize(db_engine, f["campaign"], recs, preview=True)
        invs1 = {r.generated_invoice_number for r in res1["rows"]}
        invs2 = {r.generated_invoice_number for r in res2["rows"]}
>       assert len(invs1) == 8 and len(invs2) == 8
E       AssertionError: assert (5 == 8)
E        +  where 5 = len({'INV-0UK3-H4S29-6YCZP8-5707', 'INV-24LJ-W8VYM-K8YYK7-1549', 'INV-7UQ9-U7DMH-E099PJ-8308', 'INV-V6TV-P8ZN6-0AQHHV-7787', 'INV-X1X6-YG90W-PGOBMA-0206'})

tests/test_campaign_engine.py:199: AssertionError
=========================== short test summary info ============================
FAILED tests/test_campaign_engine.py::TestMaterializeCampaign::test_invoice_numbers_unique_across_materialize_calls
ERROR tests/test_campaign_engine.py::TestMaterializeCampaign::test_invoice_numbers_unique_across_materialize_calls
1 failed, 1 passed, 1 error in 6.88s