test: add coverage for Incorrect Serial No Valuation report

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

erpnext/stock/report/incorrect_serial_no_valuation/test_incorrect_serial_no_valuation.py

@@ -0,0 +1,66 @@
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+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
+
+
+class TestIncorrectSerialNoValuation(ERPNextTestSuite):
+	def run_report(self, **extra):
+		filters = frappe._dict({"company": "_Test Company"})
+		filters.update(extra)
+		return execute(filters)[1]
+
+	def make_serial_item(self):
+		return make_item(
+			properties={
+				"is_stock_item": 1,
+				"has_serial_no": 1,
+				"serial_no_series": "ISV-.#####",
+			}
+		).name
+
+	def test_healthy_serial_item_not_flagged(self):
+		item = self.make_serial_item()
+
+		make_stock_entry(
+			item_code=item,
+			to_warehouse="_Test Warehouse - _TC",
+			qty=3,
+			rate=100,
+			posting_date="2026-06-01",
+		)
+		make_stock_entry(
+			item_code=item,
+			from_warehouse="_Test Warehouse - _TC",
+			qty=1,
+			posting_date="2026-06-02",
+		)
+
+		data = self.run_report(item_code=item)
+
+		flagged_items = {row.get("item_code") for row in data if isinstance(row, dict)}
+		self.assertNotIn(item, flagged_items)
+
+	def test_only_balance_row_when_filtered_to_healthy_item(self):
+		item = self.make_serial_item()
+
+		make_stock_entry(
+			item_code=item,
+			to_warehouse="_Test Warehouse - _TC",
+			qty=3,
+			rate=100,
+			posting_date="2026-06-01",
+		)
+
+		data = self.run_report(item_code=item)
+
+		# The report always appends a single "Balance" summary row. A healthy
+		# serial item contributes no detail rows, so only that summary remains.
+		self.assertEqual(len(data), 1)
+		self.assertEqual(data[-1].get("qty"), 0)
+		self.assertEqual(data[-1].get("valuation_rate"), 0)