diff --git a/tests/test_cache_manager.py b/tests/test_cache_manager.py
new file mode 100644
index 0000000..5cbdefe
--- /dev/null
+++ b/tests/test_cache_manager.py
@@ -0,0 +1,100 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def test_cache_service_reexports_cache_manager_state():
+    from services import cache_manager, cache_service
+
+    assert cache_service._SALES_DF_CACHE is cache_manager._SALES_DF_CACHE
+    assert cache_service._SALES_PROCESSED_CACHE is cache_manager._SALES_PROCESSED_CACHE
+    assert cache_service._SALES_OPTIONS_CACHE is cache_manager._SALES_OPTIONS_CACHE
+    assert cache_service._SALES_ANALYSIS_RESULT_CACHE is cache_manager._SALES_ANALYSIS_RESULT_CACHE
+    assert cache_service._DASHBOARD_DATA_CACHE is cache_manager._DASHBOARD_DATA_CACHE
+
+
+def test_routes_share_sales_cache_manager_state():
+    from services import cache_manager
+    from routes import export_routes, import_routes, sales_routes
+
+    sales_df_cache, sales_processed_cache, clear_for_table = import_routes._get_cache_refs()
+
+    assert sales_routes._SALES_PROCESSED_CACHE is cache_manager._SALES_PROCESSED_CACHE
+    assert export_routes._get_sales_cache() is cache_manager._SALES_PROCESSED_CACHE
+    assert sales_df_cache is cache_manager._SALES_DF_CACHE
+    assert sales_processed_cache is cache_manager._SALES_PROCESSED_CACHE
+    assert clear_for_table is cache_manager.clear_sales_cache_for_table
+
+
+def test_clear_sales_cache_for_table_removes_table_and_range_aliases():
+    from services import cache_manager
+
+    cache_manager.clear_sales_cache()
+    cache_manager._SALES_DF_CACHE["realtime_sales_monthly"] = object()
+    cache_manager._SALES_DF_CACHE["other_table"] = object()
+    cache_manager._SALES_PROCESSED_CACHE.update({
+        "realtime_sales_monthly": {"df": "base"},
+        "realtime_sales_monthly_1m": {"df": "range"},
+        "realtime_sales_monthly_custom_2026-01-01_2026-01-31": {"df": "custom"},
+        "other_table": {"df": "other"},
+    })
+
+    cache_manager.clear_sales_cache_for_table("realtime_sales_monthly")
+
+    assert "realtime_sales_monthly" not in cache_manager._SALES_DF_CACHE
+    assert "other_table" in cache_manager._SALES_DF_CACHE
+    assert "realtime_sales_monthly" not in cache_manager._SALES_PROCESSED_CACHE
+    assert "realtime_sales_monthly_1m" not in cache_manager._SALES_PROCESSED_CACHE
+    assert "realtime_sales_monthly_custom_2026-01-01_2026-01-31" not in cache_manager._SALES_PROCESSED_CACHE
+    assert "other_table" in cache_manager._SALES_PROCESSED_CACHE
+
+
+def test_set_sales_processed_cache_adds_timestamp_and_aliases():
+    from services import cache_manager
+
+    cache_manager.clear_sales_cache()
+    entry = {"df": "data", "cols": {"date": "日期"}}
+
+    cache_manager.set_sales_processed_cache(
+        "realtime_sales_monthly_3m",
+        entry,
+        aliases=("realtime_sales_monthly",),
+    )
+
+    cached = cache_manager._SALES_PROCESSED_CACHE["realtime_sales_monthly_3m"]
+    assert cached is entry
+    assert cached["time"] > 0
+    assert cache_manager._SALES_PROCESSED_CACHE["realtime_sales_monthly"] is entry
+
+
+def test_dashboard_cache_clear_restores_expected_shape():
+    from services import cache_manager
+
+    cache_manager._DASHBOARD_DATA_CACHE["consolidated_data"] = ["stale"]
+    cache_manager._DASHBOARD_DATA_CACHE["full_data"] = ["stale"]
+
+    cache_manager.clear_dashboard_cache()
+
+    assert cache_manager._DASHBOARD_DATA_CACHE == {
+        "consolidated_data": None,
+        "consolidated_timestamp": None,
+        "today_start": None,
+        "full_data": None,
+        "full_timestamp": None,
+    }
+
+
+def test_cache_dicts_are_only_defined_in_cache_manager():
+    assignments = []
+    for path in [ROOT / "app.py", *ROOT.glob("routes/*.py"), *ROOT.glob("services/*.py")]:
+        text = path.read_text(encoding="utf-8")
+        for marker in ("_SALES_DF_CACHE = {}", "_SALES_PROCESSED_CACHE = {}", "_DASHBOARD_DATA_CACHE = {"):
+            if marker in text:
+                assignments.append((path.relative_to(ROOT).as_posix(), marker))
+
+    assert assignments == [
+        ("services/cache_manager.py", "_SALES_DF_CACHE = {}"),
+        ("services/cache_manager.py", "_SALES_PROCESSED_CACHE = {}"),
+        ("services/cache_manager.py", "_DASHBOARD_DATA_CACHE = {"),
+    ]