From 482904b591da6a43003b95c4404e1a123c2fddb2 Mon Sep 17 00:00:00 2001
From: im47cn <67424112+im47cn@users.noreply.github.com>
Date: Sun, 12 Jul 2026 13:52:49 +0800
Subject: [PATCH] =?UTF-8?q?test(panelcache):=20=E5=AD=90=E4=BB=A3=E7=90=86?=
 =?UTF-8?q?=E5=AE=A1=E6=9F=A5=E5=8A=A0=E5=9B=BA=20=E2=80=94=20=E5=8E=BB=20?=
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三处审查驱动的测试改进:
- 并发计数测试放宽 reuse_count==4 为 reuse+hit==4 (保留"只扫盘1次"核心不变量),
  消除慢调度下 leader 已写缓存致某线程走 hit 分支的 flaky。
- _FakeEngine 零值 dict 改从 PanelCache().stats() 取键 —— 字段重命名时桩自动跟随,
  杜绝 test 绿而生产 cache_stats KeyError 的契约漂移。
- 新增 test_walkforward_cache_telemetry_computes_deltas: 递增桩验证 scans/hits/
  reuses/秒数 = after-before, 覆盖此前 _FakeEngine 恒返 0 掩盖的差值/顺序逻辑。
---
 backend/tests/backtest/test_walkforward.py | 34 ++++++++++++++++++++--
 backend/tests/test_backtest_etf.py         |  5 +++-
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/backend/tests/backtest/test_walkforward.py b/backend/tests/backtest/test_walkforward.py
index 8fbc95f..df49071 100644
--- a/backend/tests/backtest/test_walkforward.py
+++ b/backend/tests/backtest/test_walkforward.py
@@ -136,11 +136,14 @@ class _FakeOptimizer:
         return {"best_params": {"p": cfg.start.month}, "best_score": 2.0, "results": [], "n_completed": 1}
 
 
-_ZERO_CACHE_STATS = {"compute_seconds": 0.0, "compute_count": 0, "hit_count": 0, "reuse_count": 0}
+# 从真实 PanelCache 取字段模板 —— 字段被重命名时本桩自动跟随, 避免 test 绿而生产 KeyError。
+from app.backtest.engine import PanelCache
+
+_ZERO_CACHE_STATS = {k: type(v)() for k, v in PanelCache().stats().items()}
 
 
 class _FakeEngine:
-    """最小引擎桩: 仅提供 WF 遥测所需的 cache_stats。"""
+    """最小引擎桩: 仅提供 WF 遥测所需的 cache_stats (字段同源自 PanelCache.stats)。"""
     def cache_stats(self):
         return dict(_ZERO_CACHE_STATS)
 
@@ -182,6 +185,33 @@ def test_walkforward_optimizes_train_applies_oos():
     assert svc.calls[0]["start"] >= opt.train_ranges[0][1]
 
 
+class _CountingEngine:
+    """首尾两次 cache_stats 返回不同值, 用于验证 WF 遥测差值/顺序计算 (非全零掩盖)。"""
+    def __init__(self):
+        self._n = 0
+
+    def cache_stats(self):
+        self._n += 1
+        if self._n == 1:  # run 开头快照 (before)
+            return {"compute_seconds": 1.0, "compute_count": 2, "hit_count": 0, "reuse_count": 0}
+        return {"compute_seconds": 3.5, "compute_count": 7, "hit_count": 4, "reuse_count": 3}  # after
+
+
+def test_walkforward_cache_telemetry_computes_deltas():
+    """cache_telemetry 用首尾快照差值: scans/hits/reuses/秒数 = after - before, 且方向正确。"""
+    opt, svc = _FakeOptimizer(), _FakeService()
+    svc.engine = _CountingEngine()
+    wf = WalkForwardService(opt, svc, strategy_engine=None)
+    out = wf.run(_wf_cfg())
+
+    tel = out["cache_telemetry"]
+    assert tel["scans"] == 5          # 7 - 2, 顺序写反会得 -5
+    assert tel["hits"] == 4           # 4 - 0
+    assert tel["single_flight_reuses"] == 3  # 3 - 0
+    assert abs(tel["load_panel_seconds"] - 2.5) < 1e-9  # 3.5 - 1.0
+    assert tel["load_panel_pct"] >= 0.0  # 扫盘耗时 / WF总耗时, 非负
+
+
 def test_walkforward_reports_degradation():
     opt, svc = _FakeOptimizer(), _FakeService()
     wf = WalkForwardService(opt, svc, strategy_engine=None)
diff --git a/backend/tests/test_backtest_etf.py b/backend/tests/test_backtest_etf.py
index f95e25e..3253e1a 100644
--- a/backend/tests/test_backtest_etf.py
+++ b/backend/tests/test_backtest_etf.py
@@ -187,8 +187,11 @@ def test_panel_cache_stats_counts_scans_hits_reuses():
         t.join()
 
     s = cache.stats()
+    # 核心不变量: 5 线程并发同 key 只扫盘 1 次 (args1 首次 + args2 一次 = 2)。
     assert s["compute_count"] == 2, "并发同 key 应只扫盘 1 次"
-    assert s["reuse_count"] == 4, "其余 4 个跟随者应计为复用"
+    # 其余 4 线程要么 single-flight 复用, 要么(慢调度下 leader 已写缓存)命中 ——
+    # 二者之和恒为 4。不锁定 reuse/hit 具体分配, 避免时序 flaky。
+    assert s["reuse_count"] + (s["hit_count"] - 1) == 4, "4 个非 leader 线程应复用或命中"
 
 
 def test_job_key_includes_asset_type_and_is_consistent():