test: add test cases for SO
diff --git a/erpnext/selling/doctype/sales_order/test_sales_order.py b/erpnext/selling/doctype/sales_order/test_sales_order.py
index 627914f..03b5c4d 100644
--- a/erpnext/selling/doctype/sales_order/test_sales_order.py
+++ b/erpnext/selling/doctype/sales_order/test_sales_order.py
@@ -1878,6 +1878,140 @@
 		self.assertEqual(pe.references[1].reference_name, so.name)
 		self.assertEqual(pe.references[1].allocated_amount, 300)
 
+	def test_stock_reservation_against_sales_order(self) -> None:
+		from random import randint, uniform
+
+		from erpnext.controllers.status_updater import OverAllowanceError
+		from erpnext.stock.doctype.stock_reservation_entry.stock_reservation_entry import (
+			cancel_stock_reservation_entries,
+			get_sre_reserved_qty_details_for_voucher,
+			get_stock_reservation_entries_for_voucher,
+			has_reserved_stock,
+		)
+		from erpnext.stock.doctype.stock_reservation_entry.test_stock_reservation_entry import (
+			create_items,
+			create_material_receipts,
+			update_stock_settings,
+		)
+
+		items_details, warehouse = create_items(), "_Test Warehouse - _TC"
+		create_material_receipts(items_details, warehouse, qty=10)
+
+		item_list = []
+		for item_code, properties in items_details.items():
+			stock_uom = properties.stock_uom
+			item_list.append(
+				{
+					"item_code": item_code,
+					"warehouse": warehouse,
+					"qty": flt(uniform(11, 100), 0 if stock_uom == "Nos" else 3),
+					"uom": stock_uom,
+					"rate": randint(10, 200),
+				}
+			)
+
+		so = make_sales_order(
+			item_list=item_list,
+			warehouse="_Test Warehouse - _TC",
+		)
+
+		# Test - 1: `ValidationError` should be thrown, if Stock Reservation is disabled in Stock Settings.
+		update_stock_settings("enable_stock_reservation", 0)
+		self.assertRaises(frappe.ValidationError, so.create_stock_reservation_entries)
+
+		# Enable Stock Reservation.
+		update_stock_settings("enable_stock_reservation", 1)
+
+		# Test - 2: Stock should not be reserved if the Available Qty to Reserve is less than the Ordered Qty and Partial Reservation is disabled in Stock Settings.
+		update_stock_settings("allow_partial_reservation", 0)
+		so.create_stock_reservation_entries()
+		self.assertFalse(has_reserved_stock("Sales Order", so.name))
+
+		# Test - 3: Stock should be Partially Reserved if the Partial Reservation is enabled in Stock Settings.
+		update_stock_settings("allow_partial_reservation", 1)
+		so.create_stock_reservation_entries()
+		so.load_from_db()
+		self.assertTrue(has_reserved_stock("Sales Order", so.name))
+
+		for item in so.items:
+			sre_details = get_stock_reservation_entries_for_voucher(
+				"Sales Order", so.name, item.name, fields=["reserved_qty", "status"]
+			)
+			self.assertEqual(item.stock_reserved_qty, sre_details[0].reserved_qty)
+			self.assertEqual(sre_details[0].status, "Partially Reserved")
+
+		# Test - 4: Stock should be fully Reserved if the Available Qty to Reserve is greater than the Un-reserved Qty.
+		create_material_receipts(items_details, warehouse, qty=100)
+		so.create_stock_reservation_entries()
+		so.load_from_db()
+
+		reserved_qty_details = get_sre_reserved_qty_details_for_voucher("Sales Order", so.name)
+		for item in so.items:
+			reserved_qty = reserved_qty_details[(item.name, item.warehouse)]
+			self.assertEqual(item.stock_reserved_qty, reserved_qty)
+			self.assertEqual(item.stock_qty, item.stock_reserved_qty)
+
+		# Test - 5: Stock should get unreserved on cancellation of Stock Reservation Entries.
+		cancel_stock_reservation_entries("Sales Order", so.name)
+		so.load_from_db()
+		self.assertFalse(has_reserved_stock("Sales Order", so.name))
+
+		for item in so.items:
+			self.assertEqual(item.stock_reserved_qty, 0)
+
+		# Test - 6: Re-reserve the stock.
+		so.create_stock_reservation_entries()
+		self.assertTrue(has_reserved_stock("Sales Order", so.name))
+
+		# Test - 7: Stock should get unreserved on cancellation of Sales Order.
+		so.cancel()
+		so.load_from_db()
+		self.assertFalse(has_reserved_stock("Sales Order", so.name))
+
+		for item in so.items:
+			self.assertEqual(item.stock_reserved_qty, 0)
+
+		# Create Sales Order and Reserve Stock.
+		so = make_sales_order(
+			item_list=item_list,
+			warehouse="_Test Warehouse - _TC",
+		)
+		so.create_stock_reservation_entries()
+
+		# Test - 8: Partial Delivery against Sales Order.
+		dn1 = make_delivery_note(so.name)
+
+		for item in dn1.items:
+			item.qty = flt(uniform(1, 10), 0 if item.stock_uom == "Nos" else 3)
+
+		dn1.save()
+		dn1.submit()
+
+		for item in so.items:
+			sre_details = get_stock_reservation_entries_for_voucher(
+				"Sales Order", so.name, item.name, fields=["delivered_qty", "status"]
+			)
+			self.assertGreater(sre_details[0].delivered_qty, 0)
+			self.assertEqual(sre_details[0].status, "Partially Delivered")
+
+		# Test - 9: Over Delivery against Sales Order, should throw `OverAllowanceError` if Over Allowance is not set.
+		update_stock_settings("over_delivery_receipt_allowance", 0)
+		dn2 = make_delivery_note(so.name)
+
+		for item in dn2.items:
+			item.qty += flt(uniform(1, 10), 0 if item.stock_uom == "Nos" else 3)
+
+		dn2.save()
+		self.assertRaises(OverAllowanceError, dn2.submit)
+
+		# Test - 10: Over Delivery against Sales Order when Over Allowance is set.
+		update_stock_settings("over_delivery_receipt_allowance", 100)
+		dn2.submit()
+		update_stock_settings("over_delivery_receipt_allowance", 0)
+
+		# Test - 11: SRE Delivered Qty should be equal to the SRE Reserved Qty.
+		so.load_from_db()
+
 
 def automatically_fetch_payment_terms(enable=1):
 	accounts_settings = frappe.get_doc("Accounts Settings")