[REF] mrp_account: add an extra_cost notion on the manufacturing order

This is a preliminary work to handle the price of subcontracting. We put
this field in the generic `mrp_account` module because we also want to
support adding an extra cost on a finished move without having to work
with the wokorders, on a future task.

task 1831382

addons/mrp_account/models/mrp_production.py

@@ -14,6 +14,8 @@ class MrpProductionWorkcenterLineTime(models.Model):
 class MrpProduction(models.Model):
     _inherit = 'mrp.production'
 
+    extra_cost = fields.Float(copy=False, help='Extra cost per produced unit')
+
     def _cal_price(self, consumed_moves):
         """Set a price unit on the finished move according to `consumed_moves`.
         """
@@ -29,8 +31,9 @@ class MrpProduction(models.Model):
                 work_center_cost += (duration / 60.0) * work_order.workcenter_id.costs_hour
             if finished_move.product_id.cost_method in ('fifo', 'average'):
                 qty_done = finished_move.product_uom._compute_quantity(finished_move.quantity_done, finished_move.product_id.uom_id)
-                finished_move.price_unit = (sum([-m.value for m in consumed_moves]) + work_center_cost) / qty_done
-                finished_move.value = sum([-m.value for m in consumed_moves]) + work_center_cost
+                extra_cost = self.extra_cost * qty_done
+                finished_move.price_unit = (sum([-m.value for m in consumed_moves]) + work_center_cost + extra_cost) / qty_done
+                finished_move.value = sum([-m.value for m in consumed_moves]) + work_center_cost + extra_cost
         return True
 
     def _prepare_wc_analytic_line(self, wc_line):

addons/mrp_account/tests/test_mrp_account.py

@@ -73,6 +73,7 @@ class TestMrpAccount(common.TransactionCase):
         production_table_form.product_qty = 5.0
         production_table = production_table_form.save()
 
+        production_table.extra_cost = 20
         production_table.action_confirm()
 
         produce_form = Form(self.env['mrp.product.produce'].with_context({
@@ -85,8 +86,8 @@ class TestMrpAccount(common.TransactionCase):
         production_table.post_inventory()
         move_value = production_table.move_finished_ids.filtered(lambda x: x.state == "done").value
 
-        # 1 table head at 20 + 4 table leg at 15 + 4 bolt at 10 + 10 screw at 10
-        self.assertEqual(move_value, 121, 'Thing should have the correct price')
+        # 1 table head at 20 + 4 table leg at 15 + 4 bolt at 10 + 10 screw at 10 + 1*20 (extra cost)
+        self.assertEqual(move_value, 141, 'Thing should have the correct price')
 
 #        produce_wizard = self.env['mrp.product.produce'].with_context({
 #            'active_id': production_table.id,