[fix] race condition

test/test_sandbox_usecase.py

@@ -32,6 +32,23 @@ class FakeLogger:
         self.messages.append(('error', message, attrs))
 
 
+class FakeLockContext:
+    def __enter__(self) -> None:
+        return None
+
+    def __exit__(self, exc_type, exc, traceback) -> None:
+        return None
+
+
+class FakeLocker:
+    def __init__(self) -> None:
+        self.chat_ids: list[str] = []
+
+    def lock(self, chat_id: str) -> FakeLockContext:
+        self.chat_ids.append(chat_id)
+        return FakeLockContext()
+
+
 class FakeRuntime:
     def __init__(self) -> None:
         self.create_calls: list[dict[str, object]] = []
@@ -80,8 +97,10 @@ def test_create_sandbox_reuses_active_session_when_not_expired() -> None:
     repository.save(session)
     runtime = FakeRuntime()
     logger = FakeLogger()
+    locker = FakeLocker()
     usecase = CreateSandbox(
         repository=repository,
+        locker=locker,
         runtime=runtime,
         clock=FakeClock(now),
         logger=logger,
@@ -94,6 +113,7 @@ def test_create_sandbox_reuses_active_session_when_not_expired() -> None:
     assert runtime.create_calls == []
     assert runtime.stop_calls == []
     assert repository.get_active_by_chat_id('chat-1') == session
+    assert locker.chat_ids == ['chat-1']
     assert logger.messages == [
         (
             'info',
@@ -123,8 +143,10 @@ def test_create_sandbox_replaces_expired_session_and_creates_new_one(
     repository.save(expired_session)
     runtime = FakeRuntime()
     logger = FakeLogger()
+    locker = FakeLocker()
     usecase = CreateSandbox(
         repository=repository,
+        locker=locker,
         runtime=runtime,
         clock=FakeClock(now),
         logger=logger,
@@ -152,6 +174,7 @@ def test_create_sandbox_replaces_expired_session_and_creates_new_one(
         expires_at=now + timedelta(minutes=5),
     )
     assert repository.get_active_by_chat_id('chat-1') == result
+    assert locker.chat_ids == ['chat-1']
     assert logger.messages == [
         (
             'info',
@@ -179,8 +202,10 @@ def test_create_sandbox_creates_new_session_when_none_exists() -> None:
     repository = InMemorySandboxSessionRepository()
     runtime = FakeRuntime()
     logger = FakeLogger()
+    locker = FakeLocker()
     usecase = CreateSandbox(
         repository=repository,
+        locker=locker,
         runtime=runtime,
         clock=FakeClock(now),
         logger=logger,
@@ -203,6 +228,7 @@ def test_create_sandbox_creates_new_session_when_none_exists() -> None:
     }
     assert runtime.stop_calls == []
     assert repository.get_active_by_chat_id('chat-1') == result
+    assert locker.chat_ids == ['chat-1']
     assert logger.messages == [
         (
             'info',
@@ -248,8 +274,10 @@ def test_cleanup_expired_sandboxes_stops_and_deletes_only_expired_sessions() ->
     repository.save(active_session)
     runtime = FakeRuntime()
     logger = FakeLogger()
+    locker = FakeLocker()
     usecase = CleanupExpiredSandboxes(
         repository=repository,
+        locker=locker,
         runtime=runtime,
         clock=FakeClock(now),
         logger=logger,
@@ -262,6 +290,7 @@ def test_cleanup_expired_sandboxes_stops_and_deletes_only_expired_sessions() ->
     assert repository.get_active_by_chat_id('chat-expired') is None
     assert repository.get_active_by_chat_id('chat-boundary') is None
     assert repository.get_active_by_chat_id('chat-active') == active_session
+    assert locker.chat_ids == ['chat-expired', 'chat-boundary']
     assert logger.messages == [
         (
             'info',