[V10.329] 延長成長分析穩定快取

tests/test_cache_manager.py

@@ -147,6 +147,34 @@ def test_growth_cache_shared_file_roundtrip(tmp_path, monkeypatch):
     assert shared_cache.exists()
 
 
+def test_growth_cache_reuses_expired_ttl_when_source_fingerprint_matches(tmp_path, monkeypatch):
+    import pickle
+    from datetime import timedelta
+    from services import cache_service
+
+    shared_cache = tmp_path / "growth_analysis_cache.pkl"
+    monkeypatch.setattr(cache_service, "_GROWTH_SHARED_CACHE_FILE", shared_cache)
+    cache_service.clear_growth_cache()
+    cache_service.set_growth_cache(
+        {"labels": ["2026-05"], "revenue": [1000]},
+        {"ytd_revenue": 1000},
+        source_fingerprint=("2026-05-17", 10),
+    )
+
+    stale_timestamp = (
+        cache_service.datetime.now(cache_service.TAIPEI_TZ)
+        - timedelta(seconds=cache_service._GROWTH_CACHE_TTL + 60)
+    )
+    cache_service._GROWTH_ANALYSIS_CACHE["timestamp"] = stale_timestamp
+    payload = pickle.loads(shared_cache.read_bytes())
+    payload["timestamp"] = stale_timestamp
+    shared_cache.write_bytes(pickle.dumps(payload, protocol=pickle.HIGHEST_PROTOCOL))
+
+    assert cache_service.is_growth_cache_valid(("2026-05-17", 10))
+    assert not cache_service.is_growth_cache_valid(("2026-05-18", 10))
+    assert not cache_service.is_growth_cache_valid()
+
+
 def test_clear_growth_cache_removes_shared_file(tmp_path, monkeypatch):
     from services import cache_service