test: test case to validate free item is ignored when qty is zero

(cherry picked from commit a2b41a0c16)

erpnext/accounts/doctype/pricing_rule/test_pricing_rule.py

@@ -981,6 +981,12 @@ class TestPricingRule(FrappeTestCase):
 		self.assertEqual(so.items[1].item_code, "_Test Item")
 		self.assertEqual(so.items[1].qty, 3)
 
+		so = make_sales_order(item_code="_Test Item", qty=5, do_not_submit=1)
+		so.items[0].qty = 1
+		del so.items[-1]
+		so.save()
+		self.assertEqual(len(so.items), 1)
+
 	def test_apply_multiple_pricing_rules_for_discount_percentage_and_amount(self):
 		frappe.delete_doc_if_exists("Pricing Rule", "_Test Pricing Rule 1")
 		frappe.delete_doc_if_exists("Pricing Rule", "_Test Pricing Rule 2")