test: flag a serial with mismatched in/out valuation

erpnext/stock/report/incorrect_serial_no_valuation/test_incorrect_serial_no_valuation.py

@@ -3,6 +3,7 @@
 
 import frappe
 
+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.incorrect_serial_no_valuation.incorrect_serial_no_valuation import execute
 from erpnext.tests.utils import ERPNextTestSuite
@@ -53,3 +54,28 @@ class TestIncorrectSerialNoValuation(ERPNextTestSuite):
 		self.assertEqual(len(data), 1)
 		self.assertEqual(data[-1].get("qty"), 0)
 		self.assertEqual(data[-1].get("valuation_rate"), 0)
+
+	def test_mismatched_in_out_valuation_is_flagged(self):
+		# fresh serial item so only this test's serial movements are considered
+		item = make_item(
+			properties={"is_stock_item": 1, "has_serial_no": 1, "serial_no_series": "ISV-BAD-.#####"}
+		).name
+
+		make_stock_entry(item_code=item, to_warehouse=WAREHOUSE, qty=1, rate=100, posting_date="2026-06-01")
+		serial_no = frappe.get_all("Serial No", filters={"item_code": item}, pluck="name")[0]
+		make_stock_entry(item_code=item, from_warehouse=WAREHOUSE, qty=1, posting_date="2026-06-02")
+
+		# corrupt the outgoing valuation so the serial's in (100) and out no longer cancel:
+		# net qty is 0 but a residual value remains, which the report must flag
+		frappe.db.set_value(
+			"Serial and Batch Entry",
+			{"serial_no": serial_no, "qty": ["<", 0]},
+			"incoming_rate",
+			60,
+			update_modified=False,
+		)
+
+		data = self.run_report(item_code=item)
+
+		flagged_serials = {row.get("serial_no") for row in data if isinstance(row, dict)}
+		self.assertIn(serial_no, flagged_serials)