Add a simple test for InvoiceUpdate

invoice.go

@@ -397,6 +397,10 @@ func (c *Client) InvoiceUpdate(ctx context.Context, request *UpdateInvoiceReques
 		return err
 	}
 
+	if request.ID == "" {
+		return errors.New("missing invoice id")
+	}
+
 	body, err := json.Marshal(request)
 	if err != nil {
 		return err

invoice_test.go

@@ -72,7 +72,8 @@ func TestInvoiceAdd(t *testing.T) {
 			t.Log("New invoice", invoice.Id)
 		}
 
-		cnote, err := c.InvoiceAdd(context.Background(), &NewInvoiceRequest{
+		ctx := context.Background()
+		cnote, err := c.InvoiceAdd(ctx, &NewInvoiceRequest{
 			Invoice: &Invoice{
 				Number:         "124",
 				RelatedInvoice: "123",
@@ -92,5 +93,16 @@ func TestInvoiceAdd(t *testing.T) {
 		} else {
 			t.Log("New CreditNote", cnote.Id)
 		}
+
+		if err := c.InvoiceUpdate(ctx, &UpdateInvoiceRequest{
+			ID:    cnote.Id,
+			Title: "Some updated title",
+		}); err != nil {
+			if err != nil {
+				t.Error(err)
+			} else {
+				t.Log("Updated invoice", cnote.Id)
+			}
+		}
 	})
 }