[FIX] stock_account: partial reception with avg cost

- Create a product where the associated product category has Costing
  Method "Average Cost (AVCO)"
- Create a PO. Order 1 unit at $1000.
- Receive that unit. (System now has 1 unit at $1000).
- Create another PO. Order 3 units at $500 each.
- Receive only 1 unit and don’t create any back order.

System has 2 units @ $625, instead of $750.

The quantity computed should take into account the quantity actually
done.

opw-1843998

2 files changed, 38 insertions, 3 deletions

diff --git a/addons/stock_account/models/stock.py b/addons/stock_account/models/stock.py
index 113ff99b87a..2a7cb101c4e 100644
--- a/addons/stock_account/models/stock.py
+++ b/addons/stock_account/models/stock.py
@@ -372,6 +372,7 @@ class StockMove(models.Model):
             product_tot_qty_available = move.product_id.qty_available + tmpl_dict[move.product_id.id]
             rounding = move.product_id.uom_id.rounding
 
+            qty_done = 0.0
             if float_is_zero(product_tot_qty_available, precision_rounding=rounding):
                 new_std_price = move._get_price_unit()
             elif float_is_zero(product_tot_qty_available + move.product_qty, precision_rounding=rounding):
@@ -379,10 +380,11 @@ class StockMove(models.Model):
             else:
                 # Get the standard price
                 amount_unit = std_price_update.get((move.company_id.id, move.product_id.id)) or move.product_id.standard_price
-                qty = forced_qty or move.product_qty
-                new_std_price = ((amount_unit * product_tot_qty_available) + (move._get_price_unit() * qty)) / (product_tot_qty_available + move.product_qty)
+                qty_done = move.product_uom._compute_quantity(move.quantity_done, move.product_id.uom_id)
+                qty = forced_qty or qty_done
+                new_std_price = ((amount_unit * product_tot_qty_available) + (move._get_price_unit() * qty)) / (product_tot_qty_available + qty_done)
 
-            tmpl_dict[move.product_id.id] += move.product_qty
+            tmpl_dict[move.product_id.id] += qty_done
             # Write the standard price, as SUPERUSER_ID because a warehouse manager may not have the right to write on products
             move.product_id.with_context(force_company=move.company_id.id).sudo().write({'standard_price': new_std_price})
             std_price_update[move.company_id.id, move.product_id.id] = new_std_price
diff --git a/addons/stock_account/tests/test_stockvaluation.py b/addons/stock_account/tests/test_stockvaluation.py
index 50cc57885bb..0450d66e9a1 100644
--- a/addons/stock_account/tests/test_stockvaluation.py
+++ b/addons/stock_account/tests/test_stockvaluation.py
@@ -2489,6 +2489,39 @@ class TestStockValuation(TransactionCase):
         move2.move_line_ids.qty_done = 0
         self.assertEqual(self.product1.stock_value, -187.5)
 
+    def test_average_perpetual_4(self):
+        self.product1.product_tmpl_id.cost_method = 'average'
+
+        move1 = self.env['stock.move'].create({
+            'name': 'Receive 1 unit at 10',
+            'location_id': self.supplier_location.id,
+            'location_dest_id': self.stock_location.id,
+            'product_id': self.product1.id,
+            'product_uom': self.uom_unit.id,
+            'product_uom_qty': 1.0,
+            'price_unit': 10,
+        })
+        move1._action_confirm()
+        move1._action_assign()
+        move1.move_line_ids.qty_done = 1.0
+        move1._action_done()
+
+        move2 = self.env['stock.move'].create({
+            'name': 'Receive 3 units at 5',
+            'location_id': self.supplier_location.id,
+            'location_dest_id': self.stock_location.id,
+            'product_id': self.product1.id,
+            'product_uom': self.uom_unit.id,
+            'product_uom_qty': 3.0,
+            'price_unit': 5,
+        })
+        move2._action_confirm()
+        move2._action_assign()
+        move2.move_line_ids.qty_done = 1.0
+        move2._action_done()
+
+        self.assertAlmostEqual(self.product1.standard_price, 7.5)
+
     def test_average_negative_1(self):
         """ Test edit in the past. Receive 10, send 20, edit the second move to only send 10.
         """