test: checking balance serial nos in stock ledger report
diff --git a/erpnext/stock/report/stock_ledger/test_stock_ledger_report.py b/erpnext/stock/report/stock_ledger/test_stock_ledger_report.py
new file mode 100644
index 0000000..163b205
--- /dev/null
+++ b/erpnext/stock/report/stock_ledger/test_stock_ledger_report.py
@@ -0,0 +1,41 @@
+# Copyright (c) 2022, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+from frappe.tests.utils import FrappeTestCase
+from frappe.utils import add_days, today
+
+from erpnext.maintenance.doctype.maintenance_schedule.test_maintenance_schedule import (
+	make_serial_item_with_serial,
+)
+from erpnext.stock.doctype.delivery_note.test_delivery_note import create_delivery_note
+from erpnext.stock.doctype.serial_no.serial_no import get_serial_nos
+from erpnext.stock.report.stock_ledger.stock_ledger import execute
+
+
+class TestStockLedgerReeport(FrappeTestCase):
+	def setUp(self) -> None:
+		make_serial_item_with_serial("_Test Stock Report Serial Item")
+		self.filters = frappe._dict(
+			company="_Test Company", from_date=today(), to_date=add_days(today(), 30),
+			item_code="_Test Stock Report Serial Item"
+		)
+
+	def tearDown(self) -> None:
+		frappe.db.rollback()
+
+	def test_serial_balance(self):
+		item_code = "_Test Stock Report Serial Item"
+		# Checks serials which were added through stock in entry.
+		columns, data = execute(self.filters)
+		self.assertEqual(data[0].in_qty, 2)
+		serials_added = get_serial_nos(data[0].serial_no)
+		self.assertEqual(len(serials_added), 2)
+		# Stock out entry for one of the serials.
+		dn = create_delivery_note(item=item_code, serial_no=serials_added[1])
+		self.filters.voucher_no = dn.name
+		columns, data = execute(self.filters)
+		self.assertEqual(data[0].out_qty, -1)
+		self.assertEqual(data[0].serial_no, serials_added[1])
+		self.assertEqual(data[0].balance_serial_no, serials_added[0])
+