test: pilot core database stub helper (#3685)

tests/helpers/db_stubs.py

@@ -4,17 +4,30 @@ import types
 from unittest.mock import MagicMock
 
 
-def make_core_db_stub(monkeypatch, models=()):
+def make_core_db_stub(
+    monkeypatch,
+    models=(),
+    *,
+    attributes=None,
+    install_core_package=False,
+):
     """Create a core.database stub and inject it via monkeypatch.
 
     Always sets SessionLocal. Pass model class names via `models` to set
-    each as a MagicMock attribute on the stub.
+    each as a MagicMock attribute on the stub. Pass `attributes` to override
+    specific values, and `install_core_package` when the import also needs a
+    stub parent package.
 
     Returns the stub module for optional further configuration.
     """
+    if install_core_package:
+        monkeypatch.setitem(sys.modules, "core", types.ModuleType("core"))
+
     db = types.ModuleType("core.database")
     db.SessionLocal = MagicMock()
     for name in models:
         setattr(db, name, MagicMock())
+    for name, value in (attributes or {}).items():
+        setattr(db, name, value)
     monkeypatch.setitem(sys.modules, "core.database", db)
     return db