diff --git a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
index be20b18..623ab3f 100644
--- a/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/test_sales_invoice.py
@@ -25,6 +25,7 @@
 from erpnext.stock.doctype.purchase_receipt.test_purchase_receipt import make_purchase_receipt
 from erpnext.stock.doctype.delivery_note.delivery_note import make_sales_invoice
 from erpnext.stock.utils import get_incoming_rate
+from erpnext.accounts.utils import PaymentEntryUnlinkError
 
 class TestSalesInvoice(unittest.TestCase):
 	def make(self):
@@ -135,7 +136,7 @@
 		pe.paid_to_account_currency = si.currency
 		pe.source_exchange_rate = 1
 		pe.target_exchange_rate = 1
-		pe.paid_amount = si.grand_total
+		pe.paid_amount = si.outstanding_amount
 		pe.insert()
 		pe.submit()
 
@@ -144,6 +145,44 @@
 		self.assertRaises(frappe.LinkExistsError, si.cancel)
 		unlink_payment_on_cancel_of_invoice()
 
+	def test_payment_entry_unlink_against_standalone_credit_note(self):
+		from erpnext.accounts.doctype.payment_entry.test_payment_entry import get_payment_entry
+		si1 = create_sales_invoice(rate=1000)
+		si2 = create_sales_invoice(rate=300)
+		si3 = create_sales_invoice(qty=-1, rate=300, is_return=1)
+		
+
+		pe = get_payment_entry("Sales Invoice", si1.name, bank_account="_Test Bank - _TC")
+		pe.append('references', {
+			'reference_doctype': 'Sales Invoice',
+			'reference_name': si2.name,
+			'total_amount': si2.grand_total,
+			'outstanding_amount': si2.outstanding_amount,
+			'allocated_amount': si2.outstanding_amount
+		})
+
+		pe.append('references', {
+			'reference_doctype': 'Sales Invoice',
+			'reference_name': si3.name,
+			'total_amount': si3.grand_total,
+			'outstanding_amount': si3.outstanding_amount,
+			'allocated_amount': si3.outstanding_amount
+		})
+
+		pe.reference_no = 'Test001'
+		pe.reference_date = nowdate()
+		pe.save()
+		pe.submit()
+
+		unlink_payment_on_cancel_of_invoice()
+		si2.load_from_db()
+		si2.cancel()
+
+		si1.load_from_db()
+		self.assertRaises(PaymentEntryUnlinkError, si1.cancel)
+		unlink_payment_on_cancel_of_invoice(0)
+
+
 	def test_sales_invoice_calculation_export_currency(self):
 		si = frappe.copy_doc(test_records[2])
 		si.currency = "USD"