test: add coverage for Serial No and Batch Traceability report

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

erpnext/stock/report/serial_no_and_batch_traceability/test_serial_no_and_batch_traceability.py

@@ -0,0 +1,99 @@
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+
+from erpnext.stock.doctype.delivery_note.test_delivery_note import create_delivery_note
+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.serial_no_and_batch_traceability.serial_no_and_batch_traceability import (
+	execute,
+)
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestSerialNoAndBatchTraceability(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": "SNT-.#####",
+			}
+		).name
+
+	def test_serial_movements_traced(self):
+		"""Backward trace should surface the receipt voucher the serial came in through."""
+		item = self.make_serial_item()
+		receipt = make_stock_entry(
+			item_code=item,
+			to_warehouse="_Test Warehouse - _TC",
+			qty=2,
+			rate=100,
+			posting_date="2026-06-01",
+			company="_Test Company",
+		)
+		serial_no = frappe.get_all("Serial No", {"item_code": item}, pluck="name")[0]
+
+		rows = self.run_report(
+			item_code=item,
+			serial_nos=[serial_no],
+			traceability_direction="Backward",
+		)
+
+		traced = {row["reference_name"]: row for row in rows if row.get("reference_name")}
+		self.assertIn(receipt.name, traced)
+
+		receipt_row = traced[receipt.name]
+		self.assertEqual(receipt_row["serial_no"], serial_no)
+		self.assertEqual(receipt_row["item_code"], item)
+		self.assertEqual(receipt_row["reference_doctype"], "Stock Entry")
+		self.assertEqual(receipt_row["warehouse"], "_Test Warehouse - _TC")
+		self.assertEqual(receipt_row["direction"], "Backward")
+		self.assertGreater(receipt_row["qty"], 0)
+
+	def test_forward_and_backward_directions(self):
+		"""'Both' should trace backward to the receipt and forward to the outward delivery."""
+		item = self.make_serial_item()
+		receipt = make_stock_entry(
+			item_code=item,
+			to_warehouse="_Test Warehouse - _TC",
+			qty=2,
+			rate=100,
+			posting_date="2026-06-01",
+			company="_Test Company",
+		)
+		serial_no = frappe.get_all("Serial No", {"item_code": item}, pluck="name")[0]
+
+		delivery_note = create_delivery_note(
+			item_code=item,
+			qty=1,
+			serial_no=[serial_no],
+			warehouse="_Test Warehouse - _TC",
+			posting_date="2026-06-03",
+			company="_Test Company",
+		)
+
+		rows = self.run_report(
+			item_code=item,
+			serial_nos=[serial_no],
+			traceability_direction="Both",
+		)
+
+		traced = {row["reference_name"]: row for row in rows if row.get("reference_name")}
+
+		self.assertIn(receipt.name, traced)
+		self.assertEqual(traced[receipt.name]["direction"], "Backward")
+
+		self.assertIn(delivery_note.name, traced)
+		forward_row = traced[delivery_note.name]
+		self.assertEqual(forward_row["reference_doctype"], "Delivery Note")
+		self.assertEqual(forward_row["serial_no"], serial_no)
+		self.assertEqual(forward_row["direction"], "Forward")
+		self.assertEqual(forward_row["customer"], delivery_note.customer)
+		self.assertLess(forward_row["qty"], 0)