[FIX] point_of_sale: correctly show discount on receipt

Current behavior:
When a fiscal position is applied on an order in the PoS, the change of
price was interpreted as a discount. This shouldn't be the case.

Steps to reproduce:
- Create a tax that is included in the price (e.g. 10%)
- Create a fiscal position that match this tax and change it to no tax
- Change the pricelist option to show discount
- Create a product with a price of 100€
- Open the PoS and add the product to the order
- Apply the fiscal position
- Pay the order, and go to the receipt screen
- There is a discount showed on the receipt

opw-3154499

closes odoo/odoo#119902

X-original-commit: c7e1e634f76ef01920f7bcc7ccb43b3f28736499
Signed-off-by: Heinz Robin (rhe) <rhe@odoo.com>
Signed-off-by: Engels Robin (roen) <roen@odoo.com>

addons/point_of_sale/static/src/js/models.js

@@ -2199,7 +2199,7 @@ export class Orderline extends PosModel {
             discount: this.get_discount(),
             product_name: this.get_product().display_name,
             product_name_wrapped: this.generate_wrapped_product_name(),
-            price_lst: this.get_lst_price(),
+            price_lst: this.get_taxed_lst_unit_price(),
             fixed_lst_price: this.get_fixed_lst_price(),
             price_manually_set: this.price_manually_set,
             price_automatically_set: this.price_automatically_set,
@@ -2311,7 +2311,8 @@ export class Orderline extends PosModel {
             return this.compute_all(product_taxes, lst_price, 1, this.pos.currency.rounding)
                 .total_included;
         }
-        return lst_price;
+        var digits = this.pos.dp['Product Price'];
+        return lst_price.toFixed(digits)
     }
     get_price_without_tax() {
         return this.get_all_prices().priceWithoutTax;
@@ -3387,6 +3388,13 @@ export class Order extends PosModel {
     _get_ignored_product_ids_total_discount() {
         return [];
     }
+    _reduce_total_discount_callback(sum, orderLine) {
+        sum += (orderLine.get_unit_price() * (orderLine.get_discount()/100) * orderLine.get_quantity());
+        if (orderLine.display_discount_policy() === 'without_discount'){
+            sum += ((orderLine.get_taxed_lst_unit_price() - orderLine.get_unit_price()) * orderLine.get_quantity());
+        }
+        return sum;
+    }
     get_total_discount() {
         const ignored_product_ids = this._get_ignored_product_ids_total_discount();
         return round_pr(

addons/point_of_sale/static/tests/tours/ProductScreen.tour.js

@@ -1,6 +1,8 @@
 /** @odoo-module */
 
+import { PaymentScreen } from "@point_of_sale/../tests/tours/helpers/PaymentScreenTourMethods";
 import { ProductScreen } from "@point_of_sale/../tests/tours/helpers/ProductScreenTourMethods";
+import { ReceiptScreen } from "@point_of_sale/../tests/tours/helpers/ReceiptScreenTourMethods";
 import { TextAreaPopup } from "@point_of_sale/../tests/tours/helpers/TextAreaPopupTourMethods";
 import { getSteps, startSteps } from "@point_of_sale/../tests/tours/helpers/utils";
 import { registry } from "@web/core/registry";
@@ -142,6 +144,12 @@ ProductScreen.check.totalAmountIs('100.00');
 ProductScreen.do.changeFiscalPosition('No Tax');
 ProductScreen.check.noDiscountApplied("100.00");
 ProductScreen.check.totalAmountIs('86.96');
+ProductScreen.do.clickPayButton();
+PaymentScreen.do.clickPaymentMethod('Bank');
+PaymentScreen.check.remainingIs('0.00');
+PaymentScreen.do.clickValidate();
+ReceiptScreen.check.isShown();
+ReceiptScreen.check.noOrderlineContainsDiscount();
 
 registry.category("web_tour.tours").add("FiscalPositionNoTax", { test: true, url: "/pos/ui", steps: getSteps() });
 

addons/point_of_sale/static/tests/tours/helpers/ReceiptScreenTourMethods.js

@@ -90,6 +90,15 @@ class Check {
             },
         ];
     }
+
+    noOrderlineContainsDiscount() {
+        return [
+            {
+                trigger: `.orderlines:not(:contains('->'))`,
+                run: () => { },
+            },
+        ];
+    }
 }
 
 class Execute {