test: use fixture for payment entry test cases (#31390)

refactor: use fixture for payment entry test cases
diff --git a/erpnext/accounts/doctype/payment_entry/test_payment_entry.py b/erpnext/accounts/doctype/payment_entry/test_payment_entry.py
index a8211c8..9aa1a18 100644
--- a/erpnext/accounts/doctype/payment_entry/test_payment_entry.py
+++ b/erpnext/accounts/doctype/payment_entry/test_payment_entry.py
@@ -4,6 +4,7 @@
 import unittest
 
 import frappe
+from frappe.tests.utils import FrappeTestCase
 from frappe.utils import flt, nowdate
 
 from erpnext.accounts.doctype.payment_entry.payment_entry import (
@@ -24,7 +25,10 @@
 test_dependencies = ["Item"]
 
 
-class TestPaymentEntry(unittest.TestCase):
+class TestPaymentEntry(FrappeTestCase):
+	def tearDown(self):
+		frappe.db.rollback()
+
 	def test_payment_entry_against_order(self):
 		so = make_sales_order()
 		pe = get_payment_entry("Sales Order", so.name, bank_account="_Test Cash - _TC")