test: add correctness coverage for Stock Ledger report

The Stock Ledger report had a test stub with no assertions. Add tests for
in/out quantity split and running balance, opening-balance roll-up from
movements before the period, and item filtering, sharing a small
make_movements/run_report helper.

erpnext/stock/report/stock_ledger/test_stock_ledger_report.py

@@ -4,18 +4,86 @@
 import frappe
 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.item.test_item import make_item
+from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+from erpnext.stock.report.stock_ledger.stock_ledger import execute
 from erpnext.tests.utils import ERPNextTestSuite
 
+WAREHOUSE = "_Test Warehouse - _TC"
 
-class TestStockLedgerReeport(ERPNextTestSuite):
-	def setUp(self) -> None:
-		make_serial_item_with_serial(self, "_Test Stock Report Serial Item")
-		self.filters = frappe._dict(
+
+class TestStockLedgerReport(ERPNextTestSuite):
+	"""Correctness tests for the Stock Ledger report.
+
+	A shared `make_movements`/`run` pair keeps each test small without persisting
+	any data: movements are created per test and rolled back, while the report runs
+	read-only.
+	"""
+
+	def make_movements(self, item_code, movements):
+		for movement in movements:
+			make_stock_entry(item_code=item_code, **movement)
+
+	def run_report(self, item_code, from_date=None, to_date=None):
+		filters = frappe._dict(
 			company="_Test Company",
-			from_date=today(),
-			to_date=add_days(today(), 30),
-			item_code=["_Test Stock Report Serial Item"],
+			from_date=from_date or add_days(today(), -1),
+			to_date=to_date or today(),
+			item_code=[item_code],
+			warehouse=WAREHOUSE,
 		)
+		return list(execute(filters)[1])
+
+	def test_in_out_quantities_and_running_balance(self):
+		item = make_item().name
+		self.make_movements(
+			item,
+			[
+				{"qty": 10, "to_warehouse": WAREHOUSE, "basic_rate": 100},
+				{"qty": 4, "from_warehouse": WAREHOUSE},
+			],
+		)
+
+		rows = self.run_report(item)
+		receipt = next(row for row in rows if row.get("in_qty"))
+		issue = next(row for row in rows if row.get("out_qty"))
+
+		self.assertEqual(receipt["in_qty"], 10)
+		self.assertEqual(receipt["qty_after_transaction"], 10)
+		self.assertEqual(issue["out_qty"], -4)
+		self.assertEqual(issue["qty_after_transaction"], 6)
+
+	def test_opening_balance_reflects_movements_before_from_date(self):
+		item = make_item().name
+		self.make_movements(
+			item,
+			[
+				{
+					"qty": 10,
+					"to_warehouse": WAREHOUSE,
+					"basic_rate": 100,
+					"posting_date": add_days(today(), -10),
+				},
+				{"qty": 4, "from_warehouse": WAREHOUSE, "posting_date": today()},
+			],
+		)
+
+		rows = self.run_report(item, from_date=add_days(today(), -5), to_date=today())
+
+		# the receipt predates the range, so it surfaces as the opening balance
+		self.assertEqual(rows[0]["item_code"], "'Opening'")
+		self.assertEqual(rows[0]["qty_after_transaction"], 10)
+
+		# the in-range issue draws down from the opening balance
+		issue = next(row for row in rows if row.get("out_qty"))
+		self.assertEqual(issue["qty_after_transaction"], 6)
+
+	def test_filters_to_requested_item_only(self):
+		item_a = make_item().name
+		item_b = make_item().name
+		self.make_movements(item_a, [{"qty": 5, "to_warehouse": WAREHOUSE, "basic_rate": 100}])
+		self.make_movements(item_b, [{"qty": 7, "to_warehouse": WAREHOUSE, "basic_rate": 100}])
+
+		rows = self.run_report(item_a)
+		item_codes = {row["item_code"] for row in rows if row.get("voucher_no")}
+		self.assertEqual(item_codes, {item_a})