[FIX] stock_landed_costs: remaining_value and multiple lc

Steps to reproduce:
Create one product with FIFO and automatic inventory valuation.
Purchase product with 10 quantity and cost price 100 and mark shipment as done.
Add landed cost for done incoming shipment with 2 cost lines
E.g. 1. Freight Charges - 100
2. Duty and Charges - 50
So ideally after first outgoing shipment total cost should get updated in product is
(1000 + 100 + 50) / 10 which is 115

The issue is that we increment `remaining_value` on the wrong layer.

Fixes #41923

task-2167659

closes odoo/odoo#42871

X-original-commit: 8b89a5e4a85071055bc152b11cf150e62a5c5211
Signed-off-by: Simon Lejeune (sle) <sle@openerp.com>

addons/stock_landed_costs/models/stock_landed_cost.py

@@ -122,7 +122,7 @@ class LandedCost(models.Model):
             }
             for line in cost.valuation_adjustment_lines.filtered(lambda line: line.move_id):
                 remaining_qty = sum(line.move_id.stock_valuation_layer_ids.mapped('remaining_qty'))
-                linked_layer = line.move_id.stock_valuation_layer_ids[-1]  # Maybe the LC layer should be linked to multiple IN layer?
+                linked_layer = line.move_id.stock_valuation_layer_ids[0]
 
                 # Prorate the value at what's still in stock
                 cost_to_add = (remaining_qty / line.move_id.product_qty) * line.additional_landed_cost

addons/stock_landed_costs/tests/test_stock_landed_costs.py

@@ -34,6 +34,11 @@ class TestStockLandedCosts(TestStockLandedCostsCommon, StockAccountTestCommon):
         product_landed_cost_2.product_tmpl_id.categ_id.property_stock_account_input_categ_id = self.o_expense
         product_landed_cost_2.product_tmpl_id.categ_id.property_stock_account_output_categ_id = self.o_income
 
+        self.assertEqual(product_landed_cost_1.value_svl, 0)
+        self.assertEqual(product_landed_cost_1.quantity_svl, 0)
+        self.assertEqual(product_landed_cost_2.value_svl, 0)
+        self.assertEqual(product_landed_cost_2.quantity_svl, 0)
+
         picking_default_vals = self.env['stock.picking'].default_get(list(self.env['stock.picking'].fields_get()))
 
         # I create 2 picking moving those products
@@ -86,6 +91,11 @@ class TestStockLandedCosts(TestStockLandedCostsCommon, StockAccountTestCommon):
         picking_landed_cost_2.move_lines.quantity_done = 10
         picking_landed_cost_2.button_validate()
 
+        self.assertEqual(product_landed_cost_1.value_svl, 0)
+        self.assertEqual(product_landed_cost_1.quantity_svl, -5)
+        self.assertEqual(product_landed_cost_2.value_svl, 0)
+        self.assertEqual(product_landed_cost_2.quantity_svl, -10)
+
         # I create a landed cost for those 2 pickings
         default_vals = self.env['stock.landed.cost'].default_get(list(self.env['stock.landed.cost'].fields_get()))
         virtual_home_staging = self.env['product.product'].create({'name': 'Virtual Home Staging'})
@@ -142,3 +152,10 @@ class TestStockLandedCosts(TestStockLandedCostsCommon, StockAccountTestCommon):
         self.assertEqual(stock_landed_cost_1.state, "done")
         self.assertTrue(stock_landed_cost_1.account_move_id)
         self.assertEqual(len(stock_landed_cost_1.account_move_id.line_ids), 48)
+
+        lc_value = sum(stock_landed_cost_1.account_move_id.line_ids.filtered(lambda aml: aml.account_id.name.startswith('Expenses')).mapped('debit'))
+        product_value = abs(product_landed_cost_1.value_svl) + abs(product_landed_cost_2.value_svl)
+        self.assertEqual(lc_value, product_value)
+
+        self.assertEqual(len(picking_landed_cost_1.move_lines.stock_valuation_layer_ids), 5)
+        self.assertEqual(len(picking_landed_cost_2.move_lines.stock_valuation_layer_ids), 5)

addons/stock_landed_costs/tests/test_stockvaluationlayer.py

@@ -179,6 +179,18 @@ class TestStockValuationLCFIFO(TestStockValuationLCCommon):
         self.assertEqual(self.product1.value_svl, 0)
         self.assertEqual(self.product1.quantity_svl, 0)
 
+    def test_in_and_out_1(self):
+        move1 = self._make_in_move(self.product1, 10, unit_cost=100, create_picking=True)
+        self.assertEqual(move1.stock_valuation_layer_ids[0].remaining_value, 1000)
+        lc1 = self._make_lc(move1, 100)
+        self.assertEqual(move1.stock_valuation_layer_ids[0].remaining_value, 1100)
+        lc2 = self._make_lc(move1, 50)
+        self.assertEqual(move1.stock_valuation_layer_ids[0].remaining_value, 1150)
+        self.assertEqual(self.product1.value_svl, 1150)
+        self.assertEqual(self.product1.quantity_svl, 10)
+        move2 = self._make_out_move(self.product1, 1)
+        self.assertEqual(move2.stock_valuation_layer_ids.value, -115)
+
 
 class TestStockValuationLCAVCO(TestStockValuationLCCommon):
     def setUp(self):