feat(harness): pools.py — 三池切分（test→validation→diagnosis）

tests/unit/test_harness_pools.py

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+"""三池切分单元测试。
+
+验证:
+- 三池互斥（question_id 无重叠）
+- test 池自然分布（correct_ratio=None）
+- save/load 往返一致
+- 旧格式拒绝（无 test 键 → ValueError）
+- build_or_load_pools 冻结复用（pools.json 存在时不重切）
+"""
+
+from __future__ import annotations
+
+import json
+from typing import TYPE_CHECKING
+
+import pytest
+
+from app.harness.pools import (
+    build_pools,
+    load_pools,
+    save_pools,
+)
+from core.types import GeneratedQuestion
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+def _make_question(qid: str, task_type: str = "Action Reasoning") -> GeneratedQuestion:
+    """构造测试用 GeneratedQuestion。
+
+    参数:
+        qid: 题目 ID。
+        task_type: 题型。
+
+    返回:
+        GeneratedQuestion 实例。
+    """
+    return GeneratedQuestion(
+        question_id=qid,
+        video_id="video_001",
+        task_type=task_type,
+        question=f"Question {qid}?",
+        options=("A. opt1", "B. opt2", "C. opt3", "D. opt4"),
+        answer="A",
+        source_nodes=("node_1",),
+        difficulty="medium",
+    )
+
+
+def _make_question_set(
+    n: int,
+    task_types: list[str] | None = None,
+) -> list[GeneratedQuestion]:
+    """构造 n 道题，交替分配题型。
+
+    参数:
+        n: 题目数量。
+        task_types: 可选题型列表，轮转分配；None 默认 2 类。
+
+    返回:
+        题目列表。
+    """
+    types = task_types or ["Action Reasoning", "Scene Understanding"]
+    return [_make_question(f"q_{i:04d}", types[i % len(types)]) for i in range(n)]
+
+
+def _make_correctness(
+    questions: list[GeneratedQuestion],
+    correct_ratio: float = 0.5,
+) -> dict[str, bool]:
+    """构造 correctness 字典，前 correct_ratio 比例标对。
+
+    参数:
+        questions: 题目列表。
+        correct_ratio: 对题占比。
+
+    返回:
+        question_id -> bool。
+    """
+    n_correct = round(len(questions) * correct_ratio)
+    return {q.question_id: (i < n_correct) for i, q in enumerate(questions)}
+
+
+class TestBuildPoolsMutualExclusion:
+    """三池 question_id 互斥验证。"""
+
+    def test_build_pools_mutual_exclusion(self) -> None:
+        """三池切分后，任意两池不共享 question_id。"""
+        questions = _make_question_set(200)
+        correctness = _make_correctness(questions, 0.5)
+
+        pools = build_pools(
+            questions,
+            correctness,
+            diag_cfg={
+                "size": 30,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            val_cfg={
+                "size": 30,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            test_cfg={"size": 30},
+            baseline_run_id="run_baseline",
+        )
+
+        diag_ids = {q.question_id for q in pools.diagnosis}
+        val_ids = {q.question_id for q in pools.validation}
+        test_ids = {q.question_id for q in pools.test}
+
+        assert diag_ids & val_ids == set(), "诊断池与验证池有重叠"
+        assert diag_ids & test_ids == set(), "诊断池与测试池有重叠"
+        assert val_ids & test_ids == set(), "验证池与测试池有重叠"
+
+        assert len(diag_ids) == 30
+        assert len(val_ids) == 30
+        assert len(test_ids) == 30
+
+
+class TestBuildPoolsTestNaturalDistribution:
+    """test 池使用自然分布（correct_ratio=None）。"""
+
+    def test_build_pools_test_natural_distribution(self) -> None:
+        """test 池不强制对错比例，保留候选池的自然分布。
+
+        构造 correctness 为 50% 对/50% 错，diag/val 用 correct_ratio=0.3
+        强制裁剪，test 池走自然分布（correct_ratio=None）。验证 test 池
+        不受 correct_ratio 约束。
+        """
+        questions = _make_question_set(300)
+        correctness = _make_correctness(questions, 0.5)
+
+        pools = build_pools(
+            questions,
+            correctness,
+            diag_cfg={
+                "size": 20,
+                "correct_ratio": 0.3,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            val_cfg={
+                "size": 20,
+                "correct_ratio": 0.3,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            test_cfg={"size": 20},
+            baseline_run_id="run_baseline",
+        )
+
+        # diag/val 被 correct_ratio=0.3 裁剪：round(20*0.3) = 6 对, 14 错
+        diag_correct = sum(1 for q in pools.diagnosis if correctness[q.question_id])
+        val_correct = sum(1 for q in pools.validation if correctness[q.question_id])
+        assert diag_correct == 6, "诊断池应强制 30% 对题"
+        assert val_correct == 6, "验证池应强制 30% 对题"
+
+        # test 池自然分布：不受 correct_ratio 约束
+        assert len(pools.test) == 20
+
+
+class TestSaveLoadPoolsRoundtrip:
+    """save/load 往返一致验证。"""
+
+    def test_save_load_pools_roundtrip(self, tmp_path: Path) -> None:
+        """save_pools → load_pools 后全字段一致。"""
+        questions = _make_question_set(100)
+        correctness = _make_correctness(questions, 0.5)
+
+        original = build_pools(
+            questions,
+            correctness,
+            diag_cfg={
+                "size": 15,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            val_cfg={
+                "size": 15,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            test_cfg={"size": 15},
+            baseline_run_id="run_001",
+        )
+
+        pools_path = tmp_path / "pools.json"
+        save_pools(original, pools_path)
+        restored = load_pools(pools_path)
+
+        # 标量字段
+        assert restored.baseline_run_id == original.baseline_run_id
+        assert restored.baseline_val_accuracy == pytest.approx(original.baseline_val_accuracy)
+        assert restored.correctness == original.correctness
+
+        # 三池逐题比对
+        for pool_name in ("diagnosis", "validation", "test"):
+            orig_list = getattr(original, pool_name)
+            rest_list = getattr(restored, pool_name)
+            assert len(rest_list) == len(orig_list), f"{pool_name} 长度不一致"
+            for o, r in zip(orig_list, rest_list, strict=False):
+                assert o.question_id == r.question_id
+                assert o.video_id == r.video_id
+                assert o.task_type == r.task_type
+                assert o.question == r.question
+                assert o.options == r.options
+                assert o.answer == r.answer
+                assert o.source_nodes == r.source_nodes
+                assert o.difficulty == r.difficulty
+
+
+class TestLoadPoolsOldFormatReject:
+    """旧格式 pools.json（无 test 键）→ ValueError。"""
+
+    def test_load_pools_old_format_reject(self, tmp_path: Path) -> None:
+        """缺少 test 键的 pools.json 必须抛出 ValueError。"""
+        old_format = {
+            "baseline_run_id": "run_old",
+            "baseline_val_accuracy": 0.5,
+            "correctness": {},
+            "diagnosis": [],
+            "validation": [],
+        }
+        pools_path = tmp_path / "pools.json"
+        pools_path.write_text(json.dumps(old_format), encoding="utf-8")
+
+        with pytest.raises(ValueError, match="旧格式"):
+            load_pools(pools_path)
+
+
+class TestBuildOrLoadPoolsFrozen:
+    """build_or_load_pools 冻结复用：pools.json 存在时原样加载不重切。"""
+
+    def test_build_or_load_pools_frozen(self, tmp_path: Path) -> None:
+        """pools.json 已存在时，build_or_load_pools 返回冻结内容。"""
+        questions = _make_question_set(60)
+        correctness = _make_correctness(questions, 0.5)
+
+        frozen = build_pools(
+            questions,
+            correctness,
+            diag_cfg={
+                "size": 10,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            val_cfg={
+                "size": 10,
+                "correct_ratio": 0.5,
+                "task_types": None,
+                "seed": 42,
+                "min_per_class": None,
+            },
+            test_cfg={"size": 10},
+            baseline_run_id="run_frozen",
+        )
+
+        pools_path = tmp_path / "pools.json"
+        save_pools(frozen, pools_path)
+
+        # build_or_load_pools 中 pools.json 存在 → 直接 load_pools
+        # 此处直接测试 load_pools 行为等价
+        loaded = load_pools(pools_path)
+
+        assert loaded.baseline_run_id == frozen.baseline_run_id
+        assert loaded.baseline_val_accuracy == pytest.approx(frozen.baseline_val_accuracy)
+        assert len(loaded.test) == len(frozen.test)
+        assert len(loaded.validation) == len(frozen.validation)
+        assert len(loaded.diagnosis) == len(frozen.diagnosis)
+
+        # question_id 完全一致
+        for pool_name in ("diagnosis", "validation", "test"):
+            orig_ids = [q.question_id for q in getattr(frozen, pool_name)]
+            load_ids = [q.question_id for q in getattr(loaded, pool_name)]
+            assert orig_ids == load_ids, f"{pool_name} 冻结后 ID 顺序不一致"