Expose lease loss to execution boundaries

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a02b6f-7db1-7222-918b-e813a6bda38d

tests/test_lease_monitor.py

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+from __future__ import annotations
+
+import time
+from unittest.mock import MagicMock, patch
+
+from rein_aharness.claim_loop import _Heartbeat
+from rein_aharness.lease_monitor import LeaseMonitor
+from rein_aharness.ops_run_client import OpsRunError
+
+
+def test_loss_is_one_shot_and_bounded() -> None:
+    seen = []
+    monitor = LeaseMonitor(seen.append)
+
+    first = monitor.mark_lost("ProviderError" * 20)
+    second = monitor.mark_lost("OtherError")
+
+    assert monitor.lost is True
+    assert first == second
+    assert len(first.error_type) <= 80
+    assert first.error_type.startswith("ProviderError")
+    assert seen == [first]
+
+
+def test_wait_lost_and_stop_are_distinct() -> None:
+    monitor = LeaseMonitor()
+
+    assert monitor.wait_lost(timeout=0) is False
+    monitor.stop()
+    assert monitor.stopped is True
+    assert monitor.lost is False
+    monitor.mark_lost("OpsRunError")
+    assert monitor.wait_lost(timeout=0) is True
+
+
+def test_concurrent_loss_still_notifies_once() -> None:
+    seen = []
+    monitor = LeaseMonitor(seen.append)
+
+    import threading
+
+    threads = [threading.Thread(target=monitor.mark_lost, args=("OpsRunError",)) for _ in range(8)]
+    for thread in threads:
+        thread.start()
+    for thread in threads:
+        thread.join()
+
+    assert len(seen) == 1
+
+
+def test_heartbeat_publishes_loss_without_raw_exception_text() -> None:
+    client = MagicMock()
+    client.heartbeat.side_effect = OpsRunError("secret provider response")
+    heartbeat = _Heartbeat(client, "run-1", lease_seconds=90)
+
+    with patch("rein_aharness.claim_loop._heartbeat_interval", return_value=0.01):
+        heartbeat.start()
+        deadline = time.monotonic() + 1.0
+        while not heartbeat.monitor.lost and time.monotonic() < deadline:
+            time.sleep(0.005)
+        heartbeat.stop()
+
+    assert heartbeat.monitor.lost is True
+    assert heartbeat.monitor.evidence is not None
+    assert "secret" not in heartbeat.monitor.evidence.error_type