测试：隔离之后重新登记、收拾旧身份的两条用虚构的旧身份（不拿本进程真的身份当旧身份收拾，免得删到同一个测试进程里前面留下的、属主是它的行）

backend/tests/test_cluster.py

@@ -356,7 +356,7 @@ async def test_registering_again_tidies_up_what_the_retired_identity_left(monkey
     from app.cluster import service as service_mod
     from app.cluster.fence import now as fence_now
 
-    monkeypatch.setattr(identity, "OWNER", identity.OWNER)
+    monkeypatch.setattr(identity, "OWNER", f"{identity.host()}:{os.getpid()}:retired0")   # 测试完换回原来的身份
     old = identity.owner()
     now = utcnow()
     async with SessionLocal() as session:

backend/tests/test_cluster_fence.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 
 import asyncio
 import contextlib
+import os
 
 import pytest
 from sqlalchemy import func, select
@@ -237,7 +238,7 @@ async def test_the_lease_task_keeps_going_when_registering_again_fails(monkeypat
     from app.cluster import identity, service as service_mod, workers
     from app.cluster.version import VersionMismatch
 
-    monkeypatch.setattr(identity, "OWNER", identity.OWNER)    # 测试完换回原来的身份
+    monkeypatch.setattr(identity, "OWNER", f"{identity.host()}:{os.getpid()}:retired1")   # 测试完换回原来的身份
     monkeypatch.setattr(workers, "heartbeat_s", lambda: 0.01)
     monkeypatch.setattr(workers, "lease_s", lambda: 5.0)
     svc = service_mod._Service()