diff --git a/tests/backtest/test_cta_engine.py b/tests/backtest/test_cta_engine.py
index 7ca012c..555be72 100644
--- a/tests/backtest/test_cta_engine.py
+++ b/tests/backtest/test_cta_engine.py
@@ -1,26 +1,30 @@
 """Tests for sanguo_backtest.cta_engine module."""
 # Mock vnpy and tzlocal modules before importing anything that depends on them
 import sys
+import importlib.util
 from unittest.mock import MagicMock
 
-# Mock vnpy/tzlocal/empyrical BEFORE importing cta_engine (which imports them at top).
-# Save originals so we can RESTORE after this module — otherwise the global sys.modules
-# pollution breaks every later test that imports real vnpy/empyrical (datareader/spike/factor/metrics).
-_MOCKED_KEYS = (
-    "tzlocal", "vnpy.trader.setting", "vnpy.trader.constant", "vnpy.trader.object",
-    "vnpy.trader.database", "vnpy_ctastrategy.backtesting", "empyrical",
-)
-_SAVED_MODULES = {k: sys.modules.get(k) for k in _MOCKED_KEYS}
-
+# Only mock these when the real module is NOT importable (e.g. local env missing empyrical).
+# In the container (authoritative test env) everything imports fine, so NO mock is installed
+# → zero sys.modules pollution leaking into other test modules at collection time.
+# (Previous unconditional sys.modules[...]=MagicMock() here broke datareader/spike/factor/metrics
+# tests because it ran at collection time and never restored.)
 mock_tzlocal = MagicMock()
 mock_tzlocal.get_localzone_name = MagicMock(return_value="UTC")
-sys.modules["tzlocal"] = mock_tzlocal
-sys.modules["vnpy.trader.setting"] = MagicMock()
-sys.modules["vnpy.trader.constant"] = MagicMock()
-sys.modules["vnpy.trader.object"] = MagicMock()
-sys.modules["vnpy.trader.database"] = MagicMock()
-sys.modules["vnpy_ctastrategy.backtesting"] = MagicMock()
-sys.modules["empyrical"] = MagicMock()
+_MOCK_FACTORIES = {
+    "tzlocal": lambda: mock_tzlocal,
+    "vnpy.trader.setting": MagicMock,
+    "vnpy.trader.constant": MagicMock,
+    "vnpy.trader.object": MagicMock,
+    "vnpy.trader.database": MagicMock,
+    "vnpy_ctastrategy.backtesting": MagicMock,
+    "empyrical": MagicMock,
+}
+_SAVED_MODULES = {}
+for _name, _factory in _MOCK_FACTORIES.items():
+    if importlib.util.find_spec(_name) is None:
+        _SAVED_MODULES[_name] = sys.modules.get(_name)
+        sys.modules[_name] = _factory()
 
 import pytest
 import json