fix: improve thread safety in SQLite test sessions

Co-Authored-By: Chris Weaver <chris@onyx.app>

backend/tests/unit/onyx/db/test_users.py

@@ -5,7 +5,7 @@
 from sqlalchemy import func
 from sqlalchemy import select
 from sqlalchemy.orm import Session
-from sqlalchemy.orm import sessionmaker
+from sqlalchemy.orm.session import sessionmaker
 
 from onyx.auth.schemas import UserRole
 from onyx.db.models import User
@@ -14,10 +14,17 @@
 
 def _call_parallel(engine, email_list: List[str]) -> None:
     # Create a new session for each thread
-    SessionLocal = sessionmaker(bind=engine, expire_on_commit=False)
+    SessionLocal = sessionmaker(
+        bind=engine,
+        expire_on_commit=False,
+        autoflush=True,
+    )
     session = SessionLocal()
     try:
         batch_add_ext_perm_user_if_not_exists(session, email_list)
+    except Exception as e:
+        session.rollback()
+        raise
     finally:
         session.close()
 
@@ -49,20 +56,26 @@ def test_batch_add_ext_perm_user_if_not_exists_concurrent(
     for t in threads:
         t.join()
 
-    # Verify results - should have exactly one user per unique email (case insensitive)
-    stmt = select(User).filter(
-        func.lower(User.email).in_([email.lower() for email in emails])
-    )
-    created_users = db_session.scalars(stmt).unique().all()
+    # Create a new session for verification
+    SessionLocal = sessionmaker(bind=engine, expire_on_commit=False)
+    verify_session = SessionLocal()
+    try:
+        # Verify results - should have exactly one user per unique email (case insensitive)
+        stmt = select(User).filter(
+            func.lower(User.email).in_([email.lower() for email in emails])
+        )
+        created_users = verify_session.scalars(stmt).unique().all()
 
-    # Check total number of users (should be 2 since one email is a duplicate with different case)
-    assert len(created_users) == 2
+        # Check total number of users (should be 2 since one email is a duplicate with different case)
+        assert len(created_users) == 2
 
-    # Verify all users have the correct role
-    for user in created_users:
-        assert user.role == UserRole.EXT_PERM_USER
+        # Verify all users have the correct role
+        for user in created_users:
+            assert user.role == UserRole.EXT_PERM_USER
 
-    # Verify emails are present (case insensitive)
-    created_emails = [user.email.lower() for user in created_users]
-    assert "user1@example.com" in created_emails
-    assert "user2@example.com" in created_emails
+        # Verify emails are present (case insensitive)
+        created_emails = [user.email.lower() for user in created_users]
+        assert "user1@example.com" in created_emails
+        assert "user2@example.com" in created_emails
+    finally:
+        verify_session.close()