diff --git a/erpnext/accounts/report/payment_period_based_on_invoice_date/test_payment_period_based_on_invoice_date.py b/erpnext/accounts/report/payment_period_based_on_invoice_date/test_payment_period_based_on_invoice_date.py
new file mode 100644
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+++ b/erpnext/accounts/report/payment_period_based_on_invoice_date/test_payment_period_based_on_invoice_date.py
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+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+from frappe.utils import add_days, getdate, nowdate
+
+from erpnext.accounts.doctype.payment_entry.payment_entry import get_payment_entry
+from erpnext.accounts.doctype.sales_invoice.test_sales_invoice import create_sales_invoice
+from erpnext.accounts.report.payment_period_based_on_invoice_date.payment_period_based_on_invoice_date import (
+	execute,
+)
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestPaymentPeriodBasedOnInvoiceDate(ERPNextTestSuite):
+	"""Depth tests for the Payment Period Based On Invoice Date report.
+
+	The report lists Payment Ledger Entries against invoices and buckets the paid
+	amount by the invoice's age into ranges: range1 (0-30), range2 (30-60),
+	range3 (60-90), range4 (90 Above). The age is measured from the invoice
+	posting date up to today, so invoice posting dates are placed relative to
+	``nowdate()`` to land deterministically in a given bucket.
+	"""
+
+	def run_report(self, **extra):
+		filters = frappe._dict(
+			{
+				"company": "_Test Company",
+				"payment_type": "Incoming",
+				"party_type": "Customer",
+				"from_date": add_days(nowdate(), -180),
+				"to_date": nowdate(),
+			}
+		)
+		filters.update(extra)
+		return execute(filters)
+
+	def find_payment_row(self, data, payment_name):
+		# Row shape (positional): payment_document, payment_entry(voucher_no),
+		# party_type, party, posting_date, invoice(against_voucher_no),
+		# invoice_posting_date, due_date, amount, remarks, age,
+		# range1, range2, range3, range4, [delay_in_payment]
+		for row in data:
+			if row[1] == payment_name:
+				return row
+		return None
+
+	def pay_invoice(self, invoice):
+		pe = get_payment_entry("Sales Invoice", invoice.name)
+		pe.posting_date = nowdate()
+		pe.reference_no = "1"
+		pe.reference_date = nowdate()
+		pe.submit()
+		return pe
+
+	def test_paid_amount_lands_in_0_30_bucket(self):
+		invoice = create_sales_invoice(
+			customer="_Test Customer",
+			rate=1000,
+			posting_date=add_days(nowdate(), -15),
+		)
+		payment = self.pay_invoice(invoice)
+
+		columns, data = self.run_report()
+
+		row = self.find_payment_row(data, payment.name)
+		self.assertIsNotNone(row, "Payment row not found in report output")
+
+		# Positional assertions on the row shape.
+		self.assertEqual(row[2], "Customer")
+		self.assertEqual(row[4], getdate(nowdate()))  # payment posting date
+		self.assertEqual(row[5], invoice.name)  # against invoice
+		self.assertEqual(row[6], getdate(add_days(nowdate(), -15)))  # invoice posting date
+		self.assertEqual(row[8], 1000)  # amount
+
+		# Buckets: 0-30 filled, others empty.
+		self.assertEqual(row[11], 1000)  # range1 (0-30)
+		self.assertEqual(row[12], 0)  # range2 (30-60)
+		self.assertEqual(row[13], 0)  # range3 (60-90)
+		self.assertEqual(row[14], 0)  # range4 (90 Above)
+
+	def test_paid_amount_lands_in_30_60_bucket(self):
+		invoice = create_sales_invoice(
+			customer="_Test Customer 1",
+			rate=1000,
+			posting_date=add_days(nowdate(), -45),
+		)
+		payment = self.pay_invoice(invoice)
+
+		columns, data = self.run_report()
+
+		row = self.find_payment_row(data, payment.name)
+		self.assertIsNotNone(row, "Payment row not found in report output")
+
+		self.assertEqual(row[8], 1000)  # amount
+		# Buckets: 30-60 filled, others empty.
+		self.assertEqual(row[11], 0)  # range1 (0-30)
+		self.assertEqual(row[12], 1000)  # range2 (30-60)
+		self.assertEqual(row[13], 0)  # range3 (60-90)
+		self.assertEqual(row[14], 0)  # range4 (90 Above)
+
+	def test_columns_expose_expected_age_buckets(self):
+		columns, _data = self.run_report()
+		labels_by_fieldname = {c["fieldname"]: c["label"] for c in columns}
+		self.assertEqual(labels_by_fieldname["range1"], "0-30")
+		self.assertEqual(labels_by_fieldname["range2"], "30-60")
+		self.assertEqual(labels_by_fieldname["range3"], "60-90")
+		self.assertEqual(labels_by_fieldname["range4"], "90 Above")
+		# Sales Invoice link for Incoming payments.
+		invoice_col = next(c for c in columns if c["fieldname"] == "invoice")
+		self.assertEqual(invoice_col["options"], "Sales Invoice")
+
+	def test_invalid_payment_type_party_type_combo_throws(self):
+		# Incoming + Supplier is invalid.
+		self.assertRaises(
+			frappe.ValidationError,
+			self.run_report,
+			payment_type="Incoming",
+			party_type="Supplier",
+		)
+		# Outgoing + Customer is invalid.
+		self.assertRaises(
+			frappe.ValidationError,
+			self.run_report,
+			payment_type="Outgoing",
+			party_type="Customer",
+		)