feat(repair): 断点续跑 progress 文件管理

load_progress / save_progress(asyncio.Lock + os.replace 原子写入)
/ should_skip_video。支持并发安全的读改写和 --reaggregate-all 兜底。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/unit/test_repair_progress.py

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+"""修复管线断点续跑 progress 管理测试。"""
+from __future__ import annotations
+
+import asyncio
+import json
+
+import pytest
+
+
+def test_load_progress_missing_file(tmp_path):
+    """progress 文件不存在时返回空集合。"""
+    from tools.repair_trees import load_progress
+    result = load_progress(tmp_path / "nonexistent.json")
+    assert result == set()
+
+
+def test_load_progress_valid_file(tmp_path):
+    """正常读取已有 progress 文件。"""
+    from tools.repair_trees import load_progress
+    path = tmp_path / "progress.json"
+    path.write_text(json.dumps({"finished_video_ids": ["vid_a", "vid_b"]}))
+    result = load_progress(path)
+    assert result == {"vid_a", "vid_b"}
+
+
+def test_load_progress_corrupted_file(tmp_path):
+    """损坏的 JSON 文件返回空集合（不抛异常）。"""
+    from tools.repair_trees import load_progress
+    path = tmp_path / "progress.json"
+    path.write_text("{invalid json")
+    result = load_progress(path)
+    assert result == set()
+
+
+@pytest.mark.asyncio
+async def test_save_progress_atomic(tmp_path):
+    """save_progress 原子写入，并发调用不丢失更新。"""
+    from tools.repair_trees import save_progress
+    path = tmp_path / "progress.json"
+    lock = asyncio.Lock()
+    await save_progress(path, lock, "vid_a")
+    await save_progress(path, lock, "vid_b")
+    data = json.loads(path.read_text())
+    assert set(data["finished_video_ids"]) == {"vid_a", "vid_b"}
+
+
+@pytest.mark.asyncio
+async def test_save_progress_concurrent(tmp_path):
+    """16 路并发 save_progress 不丢失更新。"""
+    from tools.repair_trees import save_progress
+    path = tmp_path / "progress.json"
+    lock = asyncio.Lock()
+    tasks = [save_progress(path, lock, f"vid_{i}") for i in range(16)]
+    await asyncio.gather(*tasks)
+    data = json.loads(path.read_text())
+    assert len(data["finished_video_ids"]) == 16
+
+
+def test_should_skip_finished():
+    """已在 finished 集合中的视频应跳过。"""
+    from tools.repair_trees import should_skip_video
+    finished = {"vid_a", "vid_b"}
+    assert should_skip_video("vid_a", finished, reaggregate_all=False) is True
+    assert should_skip_video("vid_c", finished, reaggregate_all=False) is False
+
+
+def test_should_skip_reaggregate_all_forces_rerun():
+    """--reaggregate-all 标志强制不跳过。"""
+    from tools.repair_trees import should_skip_video
+    finished = {"vid_a"}
+    assert should_skip_video("vid_a", finished, reaggregate_all=True) is False