test: test_queue_sandbox 改 cloud 包导入，不再依赖顶层 queue 遮蔽标准库

旧写法把 cloud/ 插到 sys.path 前面再 from queue import TaskQueue：
一旦其它测试模块先 import 标准库 queue（缓进 sys.modules），本文件
即 ImportError。改成 cloud.queue / cloud.sandbox 包导入（失败时按
test_docker_sandbox.py 同款 fallback 补项目根目录），mock.patch 目标
同步改成 cloud.sandbox.*。新增 TestImportRobustness：断言标准库 queue
未被遮蔽，子进程先 import 标准库 queue 再加载本文件仍全过（子进程
以环境变量跳过自身用例防递归）。

cloud/tests/test_queue_sandbox.py

@@ -3,23 +3,30 @@
 运行（在 ~/workspace/codex-app-server 下）：
     python3 -m unittest discover -s cloud/tests -p "test_queue_sandbox.py" -v
 
-说明：cloud/ 没有 __init__.py（协调员统一创建），因此这里把 cloud/
+说明：用 cloud.queue / cloud.sandbox 包导入，绝不把 cloud/ 目录
-目录插到 sys.path 前面再导入 queue / sandbox，与 discover 的
+插到 sys.path 前面——后者会让顶层模块名 queue 遮蔽标准库 queue，
-top-level 目录无关。
+一旦有其它测试模块先 import 标准库 queue（已缓进 sys.modules），
+本文件就会 ImportError（见 TestImportRobustness 的回归证明）。
 """
 
 import json
 import os
+import subprocess
 import sys
 import unittest
+from pathlib import Path
 from types import SimpleNamespace
 from unittest import mock
 
-sys.path.insert(0, os.path.dirname(os.path.dirname(
+try:
-    os.path.abspath(__file__))))
+    from cloud.queue import TaskQueue, budget_exceeded, order_tasks, ready_tasks
-
+    from cloud.sandbox import (CloudExecutor, DockerExecutor, Executor,
-from queue import TaskQueue, budget_exceeded, order_tasks, ready_tasks
+                               LocalExecutor, _parse_goal_output,
-from sandbox import (CloudExecutor, DockerExecutor, Executor,
+                               _parse_host_result, _result_text)
+except ImportError:  # discover -s cloud/tests 时把项目根目录补进 sys.path
+    sys.path.insert(0, str(Path(__file__).resolve().parents[2]))
+    from cloud.queue import TaskQueue, budget_exceeded, order_tasks, ready_tasks
+    from cloud.sandbox import (CloudExecutor, DockerExecutor, Executor,
                                LocalExecutor, _parse_goal_output,
                                _parse_host_result, _result_text)
 
@@ -212,7 +219,7 @@ class TestExecutors(unittest.TestCase):
             {"text": text}, "unused"))
 
     def test_docker_executor_no_docker_raises_not_local(self):
-        with mock.patch("sandbox.shutil.which", return_value=None):
+        with mock.patch("cloud.sandbox.shutil.which", return_value=None):
             with self.assertRaises(RuntimeError) as ctx:
                 DockerExecutor().execute({"id": "t1"})
             self.assertIn("docker not available", str(ctx.exception))
@@ -225,7 +232,7 @@ class TestExecutors(unittest.TestCase):
             seen.append(cmd)
             return SimpleNamespace(returncode=0, stdout="ok-status")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -388,7 +395,7 @@ class TestGoalExecutors(unittest.TestCase):
             return SimpleNamespace(returncode=1, stdout="",
                                    stderr="boom")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -406,7 +413,7 @@ class TestGoalExecutors(unittest.TestCase):
             return SimpleNamespace(returncode=1, stdout="",
                                    stderr="boom")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -437,7 +444,7 @@ class TestGoalExecutors(unittest.TestCase):
             return SimpleNamespace(returncode=0, stdout=refusal,
                                    stderr="")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -493,7 +500,7 @@ class TestGoalExecutors(unittest.TestCase):
             def __init__(self, cmd, **kwargs):
                 seen.append(list(cmd))
 
-        with mock.patch("sandbox.subprocess.Popen", _FakePopen):
+        with mock.patch("cloud.sandbox.subprocess.Popen", _FakePopen):
             LocalExecutor("/fake/host.py").popen_task(
                 {"id": "t1", "prompt": "do it",
                  "verify_command": "test -f x", "goal_max_rounds": 2},
@@ -514,7 +521,7 @@ class TestGoalExecutors(unittest.TestCase):
                        "goal unmet after rounds\n",
                 stderr="")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -626,7 +633,7 @@ class TestUsageParsing(unittest.TestCase):
                        "reasoning=10 total=150 completions=2\n",
                 stderr="")
 
-        with mock.patch("sandbox.shutil.which",
+        with mock.patch("cloud.sandbox.shutil.which",
                         return_value="/usr/bin/docker"):
             executor = DockerExecutor(
                 "/fake/host.py", runner=fake_runner,
@@ -638,5 +645,57 @@ class TestUsageParsing(unittest.TestCase):
         self.assertEqual(result["usage"]["cached_input_tokens"], 40)
 
 
+class TestImportRobustness(unittest.TestCase):
+    """导入顺序回归证明：本文件绝不依赖顶层 queue 遮蔽标准库。
+
+    旧写法把 cloud/ 插到 sys.path 前面再 `from queue import ...`：
+    一旦其它测试模块先 import 标准库 queue，本文件就 ImportError。
+    新写法走 cloud.queue / cloud.sandbox 包导入，与标准库 queue
+    共存，下面的证明在两种层面都钉住这一点。
+    """
+
+    def test_stdlib_queue_not_shadowed(self):
+        # 本文件加载后，sys.modules["queue"] 仍是标准库，不是 cloud/queue.py。
+        import queue as stdlib_queue
+
+        self.assertNotIn("cloud", stdlib_queue.__file__)
+        self.assertNotIn("TaskQueue", dir(stdlib_queue))
+        # 包导入的 TaskQueue 与标准库无关。
+        from cloud.queue import TaskQueue as pkg_queue
+
+        self.assertIs(pkg_queue, TaskQueue)
+
+    def test_stdlib_queue_preimported_then_module_still_passes(self):
+        # 子进程里先 import 标准库 queue（缓进 sys.modules），再从
+        # 文件加载本模块并跑全量：旧写法在此处 ImportError，新写法全过。
+        # 子进程通过环境变量跳过本用例自身，避免无限递归派生。
+        if os.environ.get("_QUEUE_SANDBOX_ROBUSTNESS_CHILD") == "1":
+            self.skipTest("子进程内跳过，避免递归派生")
+        test_file = str(Path(__file__).resolve())
+        repo_root = str(Path(__file__).resolve().parents[2])
+        child_code = (
+            "import queue, sys\n"
+            "assert 'TaskQueue' not in dir(queue)\n"
+            "import importlib.util, unittest\n"
+            "spec = importlib.util.spec_from_file_location(\n"
+            "    'test_queue_sandbox_stdlib_first', %r)\n"
+            "mod = importlib.util.module_from_spec(spec)\n"
+            "spec.loader.exec_module(mod)\n"
+            "suite = unittest.defaultTestLoader.loadTestsFromModule(mod)\n"
+            "res = unittest.TextTestRunner(verbosity=0).run(suite)\n"
+            "sys.exit(0 if res.wasSuccessful() else 1)\n" % test_file
+        )
+        env = dict(os.environ)
+        env["_QUEUE_SANDBOX_ROBUSTNESS_CHILD"] = "1"
+        env["PYTHONPATH"] = repo_root
+        proc = subprocess.run(
+            [sys.executable, "-c", child_code],
+            env=env, cwd=repo_root, capture_output=True, text=True,
+            timeout=120)
+        self.assertEqual(proc.returncode, 0,
+                         msg=proc.stdout + proc.stderr)
+        self.assertIn("OK", proc.stderr)
+
+
 if __name__ == "__main__":
     unittest.main()