diff --git a/apps/api/tests/test_host_repair_agent.py b/apps/api/tests/test_host_repair_agent.py
index 74548f2dc..7cba547ef 100644
--- a/apps/api/tests/test_host_repair_agent.py
+++ b/apps/api/tests/test_host_repair_agent.py
@@ -9,6 +9,24 @@ import pytest
 from unittest.mock import AsyncMock, patch
 
 
+class _IsolatedRedisLock:
+    def __init__(self, *_args, **_kwargs):
+        self.acquired = False
+
+    async def acquire(self) -> bool:
+        self.acquired = True
+        return True
+
+    async def release(self) -> bool:
+        self.acquired = False
+        return True
+
+
+@pytest.fixture(autouse=True)
+def isolate_distributed_repair_lock(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr("src.core.redis_client.RedisLock", _IsolatedRedisLock)
+
+
 # =============================================================================
 # 測試 HostRepairConfig 路由
 # =============================================================================