diff --git a/erpnext/stock/report/delivery_note_trends/test_delivery_note_trends.py b/erpnext/stock/report/delivery_note_trends/test_delivery_note_trends.py
new file mode 100644
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+++ b/erpnext/stock/report/delivery_note_trends/test_delivery_note_trends.py
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+# 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.stock_entry.stock_entry_utils import make_stock_entry
+from erpnext.stock.report.delivery_note_trends.delivery_note_trends import execute
+from erpnext.tests.utils import ERPNextTestSuite
+
+ITEM = "_Test Item"
+WAREHOUSE = "Stores - _TC"
+CUSTOMER = "_Test Customer"
+
+
+class TestDeliveryNoteTrends(ERPNextTestSuite):
+	def run_report_full(self, **extra):
+		filters = frappe._dict(
+			{
+				"company": "_Test Company",
+				"fiscal_year": "_Test Fiscal Year 2026",
+				"period": "Yearly",
+				"based_on": "Item",
+				"group_by": "",
+			}
+		)
+		filters.update(extra)
+		columns, data = execute(filters)[:2]
+		return columns, data
+
+	# trend columns are "Label:fieldtype:width" strings; assert by label so the index
+	# stays correct across period / based_on / group_by combinations.
+	@staticmethod
+	def labels(columns):
+		return [c.split(":")[0] if isinstance(c, str) else c.get("label") for c in columns]
+
+	def find_row(self, columns, data, match):
+		labels = self.labels(columns)
+		for row in data:
+			if all(row[labels.index(label)] == value for label, value in match.items()):
+				return row
+		return None
+
+	def value(self, columns, row, label):
+		if not row:
+			return 0
+		return row[self.labels(columns).index(label)] or 0
+
+	def values(self, match, wanted_labels, **extra):
+		columns, data = self.run_report_full(**extra)
+		row = self.find_row(columns, data, match)
+		return {label: self.value(columns, row, label) for label in wanted_labels}
+
+	def deliver(self, qty=5, rate=200, customer=CUSTOMER, posting_date="2026-06-01"):
+		# stock the item first so the delivery note can ship, then deliver
+		make_stock_entry(
+			item_code=ITEM, to_warehouse=WAREHOUSE, qty=qty + 10, rate=100, posting_date=posting_date
+		)
+		create_delivery_note(
+			item_code=ITEM,
+			warehouse=WAREHOUSE,
+			qty=qty,
+			rate=rate,
+			customer=customer,
+			company="_Test Company",
+			posting_date=posting_date,
+		)
+
+	def test_delivery_qty_in_trend(self):
+		# A Delivery Note of qty 5 @ rate 200 sums to qty 5 / amount 1000 (base_net_amount)
+		# in the yearly bucket and the Total columns.
+		cols = ["_Test Fiscal Year 2026 (Qty)", "_Test Fiscal Year 2026 (Amt)", "Total(Qty)", "Total(Amt)"]
+		before = self.values({"Item": ITEM}, cols)
+		self.deliver()
+		after = self.values({"Item": ITEM}, cols)
+		self.assertEqual(after[cols[0]] - before[cols[0]], 5)
+		self.assertEqual(after[cols[1]] - before[cols[1]], 1000)
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+		self.assertEqual(after["Total(Amt)"] - before["Total(Amt)"], 1000)
+
+	def test_monthly_period_buckets(self):
+		cols = ["Jun (Qty)", "Jun (Amt)", "Total(Qty)", "Total(Amt)"]
+		before = self.values({"Item": ITEM}, cols, period="Monthly")
+		self.deliver(posting_date="2026-06-01")
+		after = self.values({"Item": ITEM}, cols, period="Monthly")
+		# the June delivery lands only in the June bucket, and rolls up into the Total columns
+		self.assertEqual(after["Jun (Qty)"] - before["Jun (Qty)"], 5)
+		self.assertEqual(after["Jun (Amt)"] - before["Jun (Amt)"], 1000)
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+		self.assertEqual(after["Total(Amt)"] - before["Total(Amt)"], 1000)
+
+	def test_quarterly_period_buckets(self):
+		# 2026-06-01 falls in the Apr-Jun quarter
+		cols = ["Apr-Jun (Qty)", "Apr-Jun (Amt)", "Total(Qty)"]
+		before = self.values({"Item": ITEM}, cols, period="Quarterly")
+		self.deliver(posting_date="2026-06-01")
+		after = self.values({"Item": ITEM}, cols, period="Quarterly")
+		self.assertEqual(after["Apr-Jun (Qty)"] - before["Apr-Jun (Qty)"], 5)
+		self.assertEqual(after["Apr-Jun (Amt)"] - before["Apr-Jun (Amt)"], 1000)
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+
+	def test_based_on_customer(self):
+		cols = ["Total(Qty)", "Total(Amt)"]
+		before = self.values({"Customer": CUSTOMER}, cols, based_on="Customer")
+		self.deliver(customer=CUSTOMER)
+		after = self.values({"Customer": CUSTOMER}, cols, based_on="Customer")
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+		self.assertEqual(after["Total(Amt)"] - before["Total(Amt)"], 1000)
+
+	def test_based_on_territory(self):
+		territory = frappe.db.get_value("Customer", CUSTOMER, "territory")
+		cols = ["Total(Qty)", "Total(Amt)"]
+		before = self.values({"Territory": territory}, cols, based_on="Territory")
+		self.deliver(customer=CUSTOMER)
+		after = self.values({"Territory": territory}, cols, based_on="Territory")
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+		self.assertEqual(after["Total(Amt)"] - before["Total(Amt)"], 1000)
+
+	def test_group_by_item_under_customer(self):
+		# based_on=Customer with group_by=Item produces an item-wise breakdown row
+		cols = ["Total(Qty)", "Total(Amt)"]
+		before = self.values({"Item": ITEM}, cols, based_on="Customer", group_by="Item")
+		self.deliver(customer=CUSTOMER)
+		after = self.values({"Item": ITEM}, cols, based_on="Customer", group_by="Item")
+		self.assertEqual(after["Total(Qty)"] - before["Total(Qty)"], 5)
+		self.assertEqual(after["Total(Amt)"] - before["Total(Amt)"], 1000)