✨ [feat][backend] support for_update param on read txn crud func

Author: tomy0000000

backend/kayman/crud/transaction.py

@@ -34,6 +34,7 @@ def read_transactions(
     event_id: int | Literal["empty"] | None = None,
     order_by: TransactionOrderBy | None = None,
     descending: bool = False,
+    for_update: bool = False,
 ) -> Sequence[Transaction]:
     scalar = select(Transaction)
     if transaction_id is not None:
@@ -51,5 +52,7 @@ def read_transactions(
     if order_by is not None:
         column = getattr(Transaction, order_by)
         scalar = scalar.order_by(column.desc() if descending else column.asc())
+    if for_update:
+        scalar = scalar.with_for_update()
     txns = session.exec(scalar).all()
     return txns

backend/kayman/tests/crud/test_transaction.py

@@ -1,5 +1,6 @@
 from datetime import UTC, datetime
 from decimal import Decimal
+from unittest.mock import patch
 
 from sqlmodel import Session
 
@@ -253,3 +254,13 @@ def test_read_transactions_descending_without_order_by_is_unsorted(session: Sess
     results = read_transactions(session, account_id=account.id, descending=True)
 
     assert len(results) == 3
+
+
+def test_read_transactions_for_update(session: Session):
+    TransactionFactory()
+
+    with patch.object(session, "exec", wraps=session.exec) as mock_exec:
+        read_transactions(session, for_update=True)
+        args = mock_exec.call_args[0]
+        statement = str(args[0])
+        assert "FOR UPDATE" in statement