test(client): remove polling stop race

client/tests/polling/test_coordinator.py

@@ -106,12 +106,15 @@ class FakeGateway:
     def __init__(self, outcomes: list[object] | None = None, gate: threading.Event | None = None) -> None:
         self.outcomes = list(outcomes or [None])
         self.gate = gate
+        self.entered = threading.Event()
         self.calls = 0
 
     def claim_next(self, profile_id: str):
         self.calls += 1
+        self.entered.set()
         if self.gate is not None:
-            self.gate.wait(2)
+            if not self.gate.wait(5):
+                raise RuntimeError("test_gateway_release_timeout")
         outcome = self.outcomes.pop(0) if self.outcomes else None
         if isinstance(outcome, Exception):
             raise outcome
@@ -251,7 +254,9 @@ class PollingCoordinatorTests(unittest.TestCase):
         visible: list[object] = []
         coordinator.claim_visible.connect(visible.append)
         coordinator.start()
-        wait_until(lambda: coordinator.state == PollingState.CLAIMING)
+        # CLAIMING 状态先于 queued worker 实际进入 claim_next；必须等待
+        # worker 入口，避免与 FakeGateway 的超时边界竞争而产生套件级偶发失败。
+        wait_until(lambda: coordinator.state == PollingState.CLAIMING and gateway.entered.is_set())
         coordinator._begin_claim(coordinator._epoch)
         self.assertEqual(gateway.calls, 1)
         coordinator.stop()