test(procrastinate): use async connector so run_worker can open it

SyncPsycopgConnector can defer and apply schema, but run_worker calls
open_async() under the hood and raises SyncConnectorConfigurationError
on sync connectors. Switching to PsycopgConnector — which docs say works
in both sync and async contexts — keeps the fixture sync-friendly while
making the worker happy.

Also moves _fetch_job_args off the app's connector pool (now async) and
opens its own psycopg connection for the read.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: snopoke

integration_tests/test_procrastinate.py

@@ -13,6 +13,7 @@
 import random
 
 import procrastinate
+import psycopg
 import pytest
 
 import taskbadger
@@ -37,18 +38,19 @@ def _check_log_errors(caplog):
 
 @pytest.fixture(scope="session")
 def app():
-    """A Procrastinate app pointed at a real Postgres instance with its schema applied."""
-    conn = procrastinate.SyncPsycopgConnector(conninfo=PROCRASTINATE_DSN)
+    # Async connector even though the tests are sync: run_worker raises
+    # SyncConnectorConfigurationError on SyncPsycopgConnector. Async works in both contexts.
+    conn = procrastinate.PsycopgConnector(conninfo=PROCRASTINATE_DSN)
     app = procrastinate.App(connector=conn)
     with app.open():
         # Apply schema (idempotent — Procrastinate's apply_schema is safe to re-run).
         app.schema_manager.apply_schema()
         yield app
 
 
-def _fetch_job_args(app, job_id):
-    """Read the stored ``args`` JSONB for a Procrastinate job."""
-    with app.connector.pool.connection() as conn:
+def _fetch_job_args(job_id):
+    # Direct sync psycopg connection — the app's pool is async (see fixture).
+    with psycopg.connect(PROCRASTINATE_DSN) as conn:
         with conn.cursor() as cur:
             cur.execute("SELECT args FROM procrastinate_jobs WHERE id = %s", (job_id,))
             row = cur.fetchone()
@@ -75,7 +77,7 @@ def add_manual(a, b):
 
     # The TB task id was stashed in the job kwargs at defer time. Read it back
     # from Procrastinate to verify the final state.
-    args = _fetch_job_args(app, job_id)
+    args = _fetch_job_args(job_id)
     tb_id = args["__taskbadger_task_id__"]
 
     fetched = taskbadger.get_task(tb_id)
@@ -100,7 +102,7 @@ def add_auto(a, b):
         listen_notify=False,
     )
 
-    args = _fetch_job_args(app, job_id)
+    args = _fetch_job_args(job_id)
     tb_id = args["__taskbadger_task_id__"]
 
     fetched = taskbadger.get_task(tb_id)