diff --git a/app/testing/bootstrap.py b/app/testing/bootstrap.py
index 86238f9ac..344b74e56 100644
--- a/app/testing/bootstrap.py
+++ b/app/testing/bootstrap.py
@@ -124,9 +124,11 @@ def ensure_sites_stub() -> None:
     try:
         import app.infrastructure.sites  # noqa: F401  本地已拉取时用真实模块
     except (ModuleNotFoundError, ImportError):
+        from importlib.util import spec_from_loader
         from types import ModuleType
         stub = ModuleType("app.infrastructure.sites")
         stub.SitesHelper = _SitesHelperStub
+        stub.__spec__ = spec_from_loader("app.infrastructure.sites", None)
         sys.modules["app.infrastructure.sites"] = stub
 
 
diff --git a/tests/test_legacy_import_compat.py b/tests/test_legacy_import_compat.py
index 165f55df9..ea358019b 100644
--- a/tests/test_legacy_import_compat.py
+++ b/tests/test_legacy_import_compat.py
@@ -165,6 +165,9 @@ def test_manifest_aliases_reuse_real_canonical_modules():
     code = """
 import importlib
 from app.compat.manifest import MODULE_ALIASES
+# CI 无 app.infrastructure.sites 二进制模块，先补垫片再校验全部映射（与 conftest 同源）。
+from app.testing.bootstrap import ensure_sites_stub
+ensure_sites_stub()
 
 for legacy_name, alias in MODULE_ALIASES.items():
     try:
diff --git a/tests/test_main_direct_execution.py b/tests/test_main_direct_execution.py
index 6ce3c9b59..341a120b7 100644
--- a/tests/test_main_direct_execution.py
+++ b/tests/test_main_direct_execution.py
@@ -14,6 +14,10 @@ def test_main_script_does_not_shadow_stdlib_platform(tmp_path):
         (
             "import runpy",
             "import sys",
+            # CI 无 app.infrastructure.sites 二进制模块，先补垫片再执行 main.py（与 conftest 同源）；
+            # 必须在篡改 sys.path / 摘除 platform 之前调用，避免真实模块依赖链误引被遮蔽的 app/platform。
+            "from app.testing.bootstrap import ensure_sites_stub",
+            "ensure_sites_stub()",
             f"sys.path.insert(0, {str(MAIN_PATH.parent)!r})",
             "sys.modules.pop('platform', None)",
             f"runpy.run_path({str(MAIN_PATH)!r}, run_name='pycharm_main_probe')",