test: 隔离单测中的站点原生资源 (#6452)

* test: isolate native site resources

* refactor(test): retain sites stub helper contract

* fix(test): preserve sites stub probe imports

---------

Co-authored-by: jxxghp <jxxghp@gmail.com>

tests/test_testing_bootstrap.py

@@ -9,28 +9,30 @@ from pathlib import Path
 from app.testing import bootstrap
 
 
-def test_install_sites_stub_replaces_loaded_dynamic_resource(monkeypatch):
+def test_ensure_sites_stub_replaces_loaded_dynamic_resource(monkeypatch):
     """隔离探针必须覆盖本机资源模块，保证 source-only CI 与开发机前提一致。"""
     real_module = types.ModuleType("app.application.site.sites")
     real_module.SitesHelper = object
     monkeypatch.setitem(sys.modules, "app.application.site.sites", real_module)
 
-    bootstrap.install_sites_stub()
-
-    installed = sys.modules["app.application.site.sites"]
-    assert installed is not real_module
-    assert installed.SitesHelper is bootstrap._SitesHelperStub
-
-
-def test_ensure_sites_stub_preserves_loaded_dynamic_resource(monkeypatch):
-    """常规测试引导仍应优先复用已经加载的真实站点资源。"""
-    real_module = types.ModuleType("app.application.site.sites")
-    real_module.SitesHelper = object
-    monkeypatch.setitem(sys.modules, "app.application.site.sites", real_module)
-
     bootstrap.ensure_sites_stub()
 
-    assert sys.modules["app.application.site.sites"] is real_module
+    installed = sys.modules["app.application.site.sites"]
+    assert installed is not real_module
+    assert installed.SitesHelper is bootstrap._SitesHelperStub
+
+
+def test_prepare_backend_replaces_loaded_dynamic_resource(monkeypatch):
+    """普通测试引导必须隔离源码目录中已存在的站点原生制品。"""
+    real_module = types.ModuleType("app.application.site.sites")
+    real_module.SitesHelper = object
+    monkeypatch.setitem(sys.modules, "app.application.site.sites", real_module)
+
+    bootstrap.prepare_backend()
+
+    installed = sys.modules["app.application.site.sites"]
+    assert installed is not real_module
+    assert installed.SitesHelper is bootstrap._SitesHelperStub
 
 
 def test_isolate_config_cleanup_uses_loaded_db_module_without_late_import(monkeypatch):