diff --git a/tests/conftest.py b/tests/conftest.py
index 99b08b4c..69cbd836 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,11 +9,14 @@
 import ispyb
 import pytest
 from ispyb.sqlalchemy import BLSession, ExperimentType, Person, Proposal, url
-from sqlalchemy import Engine, RootTransaction, and_, create_engine, event, select
+from sqlalchemy import Engine, and_, create_engine, event, select as sa_select
 from sqlalchemy.exc import InterfaceError
-from sqlalchemy.ext.declarative import DeclarativeMeta
-from sqlalchemy.orm import Session as SQLAlchemySession, sessionmaker
-from sqlmodel import Session as SQLModelSession, SQLModel
+from sqlalchemy.orm import (
+    Session as SQLAlchemySession,
+    SessionTransaction,
+    sessionmaker,
+)
+from sqlmodel import Session as SQLModelSession, SQLModel, select as sm_select
 
 from murfey.util.db import Session as MurfeySession
 
@@ -121,21 +124,24 @@ class ISPyBTableValues:
     }
 
 
-SQLAlchemyTable = TypeVar("SQLAlchemyTable", bound=DeclarativeMeta)
+SQLTable = TypeVar("SQLTable")
 
 
 def get_or_create_db_entry(
     session: SQLAlchemySession | SQLModelSession,
-    table: Type[SQLAlchemyTable],
-    lookup_kwargs: dict[str, Any] = {},
-    insert_kwargs: dict[str, Any] = {},
-) -> SQLAlchemyTable:
+    table: Type[SQLTable],
+    lookup_kwargs: dict[str, Any] | None = None,
+    insert_kwargs: dict[str, Any] | None = None,
+) -> SQLTable:
     """
     Helper function to facilitate looking up or creating SQLAlchemy table entries.
     Returns the entry if a match based on the lookup criteria is found, otherwise
     creates and returns a new entry.
     """
 
+    lookup_kwargs = lookup_kwargs or {}
+    insert_kwargs = insert_kwargs or {}
+
     # if lookup kwargs are provided, check if entry exists
     if lookup_kwargs:
         conditions = [
@@ -143,11 +149,11 @@ def get_or_create_db_entry(
         ]
         # Use 'exec()' for SQLModel sessions
         if isinstance(session, SQLModelSession):
-            entry = session.exec(select(table).where(and_(*conditions))).first()
+            entry = session.exec(sm_select(table).where(and_(*conditions))).first()
         # Use 'execute()' for SQLAlchemy sessions
         elif isinstance(session, SQLAlchemySession):
             entry = (
-                session.execute(select(table).where(and_(*conditions)))
+                session.execute(sa_select(table).where(and_(*conditions)))
                 .scalars()
                 .first()
             )
@@ -166,13 +172,17 @@ def get_or_create_db_entry(
 
 
 def restart_savepoint(
-    session: SQLAlchemySession | SQLModelSession, transaction: RootTransaction
+    session: SQLAlchemySession | SQLModelSession, transaction: SessionTransaction
 ):
     """
     Re-establish a SAVEPOINT after a nested transaction is committed or rolled back.
     This helps to maintain isolation across different test cases.
     """
-    if transaction.nested and not transaction._parent.nested:
+    if (
+        transaction.nested
+        and transaction._parent is not None
+        and not transaction._parent.nested
+    ):
         session.begin_nested()
 
 
@@ -255,7 +265,7 @@ def seed_ispyb_db(ispyb_db_session_factory):
     except InterfaceError:
         # If this fails in the GitHub test environment, raise it as a genuine error
         if os.getenv("GITHUB_ACTIONS") == "true":
-            raise InterfaceError
+            raise
         pytest.skip("ISPyB database has not been set up; skipping test")