diff --git a/tests/unit/test_round_trip.py b/tests/unit/test_round_trip.py
index 8c39f6e..2424d38 100644
--- a/tests/unit/test_round_trip.py
+++ b/tests/unit/test_round_trip.py
@@ -44,7 +44,7 @@ SYNTHETIC = SyntheticObservations(
 )
 
 
-class _Crash(RuntimeError):
+class _CrashError(RuntimeError):
     """模拟进程被杀。它不是存储故障，是「这个进程不存在了」。"""
 
 
@@ -62,7 +62,7 @@ class _CrashingStore:
     def _tick(self) -> None:
         self.writes += 1
         if self.writes > self._crash_after:
-            raise _Crash(f"第 {self.writes} 次写之前进程没了")
+            raise _CrashError(f"第 {self.writes} 次写之前进程没了")
 
     async def write_run_started(self, record) -> None:
         self._tick()
@@ -233,7 +233,7 @@ async def test_crashing_at_any_write_boundary_resumes_to_the_same_result(
             _definition(crashing),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.SAFE),
         )
-    except _Crash:
+    except _CrashError:
         pass
     else:
         # 崩点排在最后一次写之后，这次运行其实跑完了。
@@ -270,7 +270,7 @@ async def test_the_history_the_model_sees_after_resuming_matches_the_uninterrupt
     directory = tmp_path / "crashed"
     # 崩在第一步的步记录落盘之后（第 5 次写），第二步一个字都没写。
     crashing = _CrashingStore(JsonlRunStore(directory=directory), crash_after=5)
-    with pytest.raises(_Crash):
+    with pytest.raises(_CrashError):
         await run(
             _definition(crashing),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.SAFE),
@@ -303,7 +303,7 @@ async def test_an_unreplayable_action_stops_at_unknown_instead_of_guessing(
     registry = _registry(replay_policy=ReplayPolicy.NEVER)
     # 第 4 次写是第一步的动作意图；崩在它之后，步记录就没写。
     crashing = _CrashingStore(JsonlRunStore(directory=directory), crash_after=4)
-    with pytest.raises(_Crash):
+    with pytest.raises(_CrashError):
         await run(
             _definition(crashing),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.NEVER),
@@ -327,7 +327,7 @@ async def test_an_unreplayable_model_call_stops_at_unknown(tmp_path: Path) -> No
     registry = _registry(replay_policy=ReplayPolicy.NEVER)
     # 第 2 次写是第一步的模型调用意图。
     crashing = _CrashingStore(JsonlRunStore(directory=directory), crash_after=2)
-    with pytest.raises(_Crash):
+    with pytest.raises(_CrashError):
         await run(
             _definition(crashing),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.NEVER),
@@ -350,7 +350,7 @@ async def test_a_resumed_log_survives_a_second_resume(tmp_path: Path) -> None:
     directory = tmp_path / "twice"
     registry = _registry(replay_policy=ReplayPolicy.SAFE)
     crashing = _CrashingStore(JsonlRunStore(directory=directory), crash_after=2)
-    with pytest.raises(_Crash):
+    with pytest.raises(_CrashError):
         await run(
             _definition(crashing),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.SAFE),
@@ -358,7 +358,7 @@ async def test_a_resumed_log_survives_a_second_resume(tmp_path: Path) -> None:
 
     # 第一次续跑：重放那次模型调用，再崩在下一步的动作意图之后。
     second = _CrashingStore(JsonlRunStore(directory=directory), crash_after=3)
-    with pytest.raises(_Crash):
+    with pytest.raises(_CrashError):
         await resume(
             _definition(second),
             _request(_ScriptedExecutor(), registry, model_replay=ReplayPolicy.SAFE),