test: Gross Profit report output for Cr notes

2 New test cases added.
1. Standalone Cr notes will be reported as normal Invoices
2. Cr notes against an Invoice will not overallocate qty if there are
multiple instances of same item

(cherry picked from commit cc61daeec4)

erpnext/accounts/report/gross_profit/gross_profit.py

@@ -501,7 +501,14 @@ class GrossProfitGenerator(object):
 						):
 							returned_item_rows = self.returned_invoices[row.parent][row.item_code]
 							for returned_item_row in returned_item_rows:
-								row.qty += flt(returned_item_row.qty)
+								# returned_items 'qty' should be stateful
+								if returned_item_row.qty != 0:
+									if row.qty >= abs(returned_item_row.qty):
+										row.qty += returned_item_row.qty
+										returned_item_row.qty = 0
+									else:
+										row.qty = 0
+										returned_item_row.qty += row.qty
 								row.base_amount += flt(returned_item_row.base_amount, self.currency_precision)
 							row.buying_amount = flt(flt(row.qty) * flt(row.buying_rate), self.currency_precision)
 						if flt(row.qty) or row.base_amount:
@@ -734,6 +741,8 @@ class GrossProfitGenerator(object):
 		if self.filters.to_date:
 			conditions += " and posting_date <= %(to_date)s"
 
+		conditions += " and (is_return = 0 or (is_return=1 and return_against is null))"
+
 		if self.filters.item_group:
 			conditions += " and {0}".format(get_item_group_condition(self.filters.item_group))
 

erpnext/accounts/report/gross_profit/test_gross_profit.py

@@ -381,3 +381,82 @@ class TestGrossProfit(FrappeTestCase):
 		}
 		gp_entry = [x for x in data if x.parent_invoice == sinv.name]
 		self.assertDictContainsSubset(expected_entry, gp_entry[0])
+
+	def test_crnote_against_invoice_with_multiple_instances_of_same_item(self):
+		"""
+		Item Qty for Sales Invoices with multiple instances of same item go in the -ve. Ideally, the credit noteshould cancel out the invoice items.
+		"""
+		from erpnext.accounts.doctype.sales_invoice.sales_invoice import make_sales_return
+
+		# Invoice with an item added twice
+		sinv = self.create_sales_invoice(qty=1, rate=100, posting_date=nowdate(), do_not_submit=True)
+		sinv.append("items", frappe.copy_doc(sinv.items[0], ignore_no_copy=False))
+		sinv = sinv.save().submit()
+
+		# Create Credit Note for Invoice
+		cr_note = make_sales_return(sinv.name)
+		cr_note = cr_note.save().submit()
+
+		filters = frappe._dict(
+			company=self.company, from_date=nowdate(), to_date=nowdate(), group_by="Invoice"
+		)
+
+		columns, data = execute(filters=filters)
+		expected_entry = {
+			"parent_invoice": sinv.name,
+			"currency": "INR",
+			"sales_invoice": self.item,
+			"customer": self.customer,
+			"posting_date": frappe.utils.datetime.date.fromisoformat(nowdate()),
+			"item_code": self.item,
+			"item_name": self.item,
+			"warehouse": "Stores - _GP",
+			"qty": 0.0,
+			"avg._selling_rate": 0.0,
+			"valuation_rate": 0.0,
+			"selling_amount": -100.0,
+			"buying_amount": 0.0,
+			"gross_profit": -100.0,
+			"gross_profit_%": 100.0,
+		}
+		gp_entry = [x for x in data if x.parent_invoice == sinv.name]
+		# Both items of Invoice should have '0' qty
+		self.assertEqual(len(gp_entry), 2)
+		self.assertDictContainsSubset(expected_entry, gp_entry[0])
+		self.assertDictContainsSubset(expected_entry, gp_entry[1])
+
+	def test_standalone_cr_notes(self):
+		"""
+		Standalone cr notes will be reported as usual
+		"""
+		# Make Cr Note
+		sinv = self.create_sales_invoice(
+			qty=-1, rate=100, posting_date=nowdate(), do_not_save=True, do_not_submit=True
+		)
+		sinv.is_return = 1
+		sinv = sinv.save().submit()
+
+		filters = frappe._dict(
+			company=self.company, from_date=nowdate(), to_date=nowdate(), group_by="Invoice"
+		)
+
+		columns, data = execute(filters=filters)
+		expected_entry = {
+			"parent_invoice": sinv.name,
+			"currency": "INR",
+			"sales_invoice": self.item,
+			"customer": self.customer,
+			"posting_date": frappe.utils.datetime.date.fromisoformat(nowdate()),
+			"item_code": self.item,
+			"item_name": self.item,
+			"warehouse": "Stores - _GP",
+			"qty": -1.0,
+			"avg._selling_rate": 100.0,
+			"valuation_rate": 0.0,
+			"selling_amount": -100.0,
+			"buying_amount": 0.0,
+			"gross_profit": -100.0,
+			"gross_profit_%": 100.0,
+		}
+		gp_entry = [x for x in data if x.parent_invoice == sinv.name]
+		self.assertDictContainsSubset(expected_entry, gp_entry[0])