Simplify update code, update test improvement

saleor/graphql/order/mutations/orders.py

@@ -579,11 +579,8 @@ class Meta:
     @classmethod
     def perform_mutation(cls, _root, info, **data):
         invoice = cls.get_instance(info, **data)
-        update_fields = ("number", "url")
         with transaction.atomic():
-            invoice.update_invoice(
-                **{arg: data[arg] for arg in update_fields if data.get(arg) is not None}
-            )
+            invoice.update_invoice(number=data.get("number"), url=data.get("url"))
             invoice.status = InvoiceStatus.READY
             invoice.save()
             if not (invoice.number and invoice.url):

tests/api/test_order.py

@@ -2940,7 +2940,8 @@ def test_update_invoice(user_api_client, permission_manage_orders, orders):
 
 
 def test_update_invoice_single_value(user_api_client, permission_manage_orders, orders):
-    invoice = Invoice.objects.create(order=orders[0], number="01/12/2020/TEST")
+    number = "01/12/2020/TEST"
+    invoice = Invoice.objects.create(order=orders[0], number=number)
     url = "http://www.example.com"
     variables = {
         "id": graphene.Node.to_global_id("Invoice", invoice.pk),
@@ -2951,6 +2952,7 @@ def test_update_invoice_single_value(user_api_client, permission_manage_orders,
     content = get_graphql_content(response)
     invoice.refresh_from_db()
     assert invoice.status == InvoiceStatus.READY
+    assert invoice.number == number
     assert invoice.url == content["data"]["updateInvoice"]["invoice"]["url"]