feat: add cheater gate with resume-safe survivor recovery

tests/unit/test_adversarial_cheater_gate.py

@@ -0,0 +1,87 @@
+"""作弊门：agent 答对=filtered_too_easy 并落表；答错=cheat verdict=passed 待翻转。"""
+
+import pytest
+
+from app.question_gen.adversarial_config import AdversarialFilterConfig
+from app.question_gen.adversarial_filter import run_cheater_gate
+from app.question_gen.run_store import QuestionGenStore
+from core.types import GeneratedQuestion
+
+
+class _FakeAgent:
+    """按 question_id → 预测字母返回的 mock AgentRunner。"""
+
+    def __init__(self, preds: dict[str, str], model: str = "m1", skill_mode: str = "auto"):
+        self._preds = preds
+        self.model = model
+        self.skill_mode = skill_mode
+        self.calls: list[str] = []
+
+    async def predict(self, questions, *, max_steps, run_id):
+        self.calls.extend(q.question_id for q in questions)
+        return {q.question_id: self._preds.get(q.question_id) for q in questions}
+
+
+def _q(qid, answer="A"):
+    return GeneratedQuestion(
+        question_id=qid, video_id="v1", task_type="Action Recognition",
+        question="?", options=("A. 蒸", "B. 炒", "C. 煮", "D. 炸"), answer=answer,
+        source_nodes=("n1",), difficulty="hard", sub_pattern="temporal_reasoning_failure",
+    )
+
+
+@pytest.mark.asyncio
+async def test_cheater_gate_filters_too_easy_and_keeps_hard(tmp_path):
+    store = QuestionGenStore(str(tmp_path / "q.db"))
+    agent = _FakeAgent({"easy": "A", "hard": "B"})  # easy 答对(A), hard 答错
+    cfg = AdversarialFilterConfig()
+    survivors = await run_cheater_gate(
+        [_q("easy"), _q("hard")], agent=agent, store=store,
+        config=cfg, round_no=0, run_id="r0",
+    )
+    ids = {q.question_id for q in survivors}
+    assert ids == {"hard"}  # 只有答错的进翻转门
+    verdicts = {
+        r[0]: r[1] for r in store._conn.execute(
+            "SELECT question_id, verdict FROM adversarial_verdicts WHERE stage='cheat'"
+        )
+    }
+    assert verdicts["easy"] == "filtered_too_easy"
+    # hard 在 cheat 阶段先记 passed（待翻转门可能改写；不支持翻转的题即终判 passed）
+    assert verdicts["hard"] == "passed"
+    store.close()
+
+
+@pytest.mark.asyncio
+async def test_cheater_gate_resume_skips_completed(tmp_path):
+    store = QuestionGenStore(str(tmp_path / "q.db"))
+    agent = _FakeAgent({"hard": "B"})
+    cfg = AdversarialFilterConfig()
+    await run_cheater_gate([_q("hard")], agent=agent, store=store,
+                           config=cfg, round_no=0, run_id="r0")
+    first = list(agent.calls)
+    await run_cheater_gate([_q("hard")], agent=agent, store=store,
+                           config=cfg, round_no=0, run_id="r1")
+    assert agent.calls == first  # 第二次不重跑（已有 cheat verdict）
+    store.close()
+
+
+@pytest.mark.asyncio
+async def test_cheater_gate_resume_mixed_keeps_all_survivors(tmp_path):
+    """混合续跑：部分题已有 cheat verdict、部分未判——已完成的存活者不得被丢。"""
+    store = QuestionGenStore(str(tmp_path / "q.db"))
+    cfg = AdversarialFilterConfig()
+    # 第一轮：先只判 done_hard（答错=存活），落表
+    agent1 = _FakeAgent({"done_hard": "B"})  # 答错(正解 A)
+    await run_cheater_gate([_q("done_hard")], agent=agent1, store=store,
+                           config=cfg, round_no=0, run_id="r0")
+    # 第二轮：done_hard 已判 + 新题 new_hard 未判混在一起
+    agent2 = _FakeAgent({"new_hard": "C"})  # 新题答错(正解 A)=存活
+    survivors = await run_cheater_gate(
+        [_q("done_hard"), _q("new_hard")], agent=agent2, store=store,
+        config=cfg, round_no=0, run_id="r1",
+    )
+    ids = {q.question_id for q in survivors}
+    assert ids == {"done_hard", "new_hard"}  # 已完成存活者 done_hard 未被丢
+    assert agent2.calls == ["new_hard"]  # 只对未判题跑 agent
+    store.close()