Set shipment cost on lines

__init__.py

@@ -25,3 +25,7 @@ def register():
         module='web_shop_woocommerce', type_='wizard')
     Pool.register(
         module='web_shop_woocommerce', type_='report')
+    Pool.register(
+        web.Shop_SaleShipmentCost,
+        depends=['sale_shipment_cost'],
+        module='web_shop_woocommerce', type_='model')

tryton.cfg

@@ -7,6 +7,8 @@ depends:
     product_price_list
     sale
     web_shop
+extras_depend:
+    sale_shipment_cost
 xml:
     message.xml
     product.xml

web.py

@@ -529,3 +529,13 @@ class Sale(metaclass=PoolMeta):
         for sale in to_check:
             if sale.woocommerce_completed:
                 sale.web_shop.update_woocommerce_status([sale], 'completed')
+
+
+class Shop_SaleShipmentCost(metaclass=PoolMeta):
+    __name__ = 'web.shop'
+
+    def woocommerce_shipping_line(self, order, item, sale):
+        line = super().woocommerce_shipping_line(order, item, sale)
+        # TODO compute based on carrier, not total
+        line.shipment_cost = round_price(Decimal(str(item['total'])))
+        return line