fix(analytics): id-tiebreak snapshot ordering + rates/cn_day tests + breakdown ValueError

tests/test_analytics_health.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 
 from datetime import datetime, timezone
 
-from app.admin.repositories.analytics_health import diff_snapshots
+from app.admin.repositories.analytics_health import _cn_day, _rates, diff_snapshots
 
 
 def _row(device, epoch, event, ts, **cum) -> dict:
@@ -52,3 +52,37 @@ def test_diff_clamps_negative_on_reorder() -> None:
     ]
     out = sorted(diff_snapshots(rows), key=lambda r: r["created_at"])
     assert out[1]["d_attempted"] == 0
+
+
+def test_rates_computes_both_formulas() -> None:
+    out = _rates({"attempted": 150, "drop_capture": 0, "delivered": 140, "drop_undelivered": 10})
+    assert out["track_success_rate"] == 1.0
+    assert out["report_success_rate"] == 140 / 150
+
+
+def test_rates_zero_denominator_yields_none() -> None:
+    out = _rates({"attempted": 0, "drop_capture": 0, "delivered": 0, "drop_undelivered": 0})
+    assert out["track_success_rate"] is None
+    assert out["report_success_rate"] is None
+
+
+def test_cn_day_beijing_boundary() -> None:
+    # UTC 15:59 → 北京 23:59 同日;UTC 16:00 → 北京 次日 00:00
+    assert _cn_day(datetime(2026, 7, 1, 15, 59, tzinfo=timezone.utc)) == "2026-07-01"
+    assert _cn_day(datetime(2026, 7, 1, 16, 0, tzinfo=timezone.utc)) == "2026-07-02"
+
+
+def test_diff_same_timestamp_ordered_by_id() -> None:
+    ts = datetime(2026, 7, 1, 1, 0, tzinfo=timezone.utc)
+    # 相同 created_at,乱序传入(id=2 在前);应按 id 排序 → id=1(cum100) 在前
+    rows = [
+        {"id": 2, "device_id": "d", "epoch_id": "e", "event": "vp", "created_at": ts,
+         "app_ver": "v", "oem": "o", "os": "s",
+         "attempted": 150, "drop_capture": 0, "delivered": 0, "drop_undelivered": 0},
+        {"id": 1, "device_id": "d", "epoch_id": "e", "event": "vp", "created_at": ts,
+         "app_ver": "v", "oem": "o", "os": "s",
+         "attempted": 100, "drop_capture": 0, "delivered": 0, "drop_undelivered": 0},
+    ]
+    out = diff_snapshots(rows)
+    assert out[0]["d_attempted"] == 100  # id=1 sorts first → its cumulative
+    assert out[1]["d_attempted"] == 50   # id=2 second → 150-100