[FIX] stock: use precision_rounding instead of digits with float_is_zero

Steps to reproduce the bug:
- Create a storable product “P1”
    - UoM: gram

- Create an internal picking with 0.01g of P1
- Validate the picking
- Create a return and try to validate it

Problem:
A UserError is triggered: “Please specify at least one non-zero quantity.”

When creating a return, we check if the quantity is not zero using the
“float_is_zero” function, but we mistakenly use rounding as
precision_digits.

opw-3862142"

closes odoo/odoo#162389

Signed-off-by: Quentin Wolfs (quwo) <quwo@odoo.com>

addons/stock/tests/test_stock_return_picking.py

@@ -178,8 +178,9 @@ class TestReturnPicking(TestStockCommon):
 
     def test_return_wizard_with_partial_delivery(self):
         """
-        Create a picking for 10 units, deliver 6, and do not backorder the remaining 4.
-        Then, attempt to return the quantity that was delivered. The return should be created with the correct quantity.
+        Create a picking for 10 grams, deliver 0.01, and do not backorder the remaining quantity.
+        Then, attempt to return the quantity that was delivered. The quantity should be properly verified
+        to not be equal to 0 and the return should be created.
         """
         delivery_picking = self.PickingObj.create({
             'picking_type_id': self.picking_type_out,
@@ -188,14 +189,14 @@ class TestReturnPicking(TestStockCommon):
         })
         out_move = self.MoveObj.create({
             'name': "OUT move",
-            'product_id':self.productA.id,
+            'product_id': self.gB.id,
             'product_uom_qty': 10,
             'picking_id': delivery_picking.id,
             'location_id': self.stock_location,
             'location_dest_id': self.customer_location,
         })
         delivery_picking.action_confirm()
-        out_move.quantity = 6
+        out_move.quantity = 0.01
         # No backorder
         res_dict = delivery_picking.with_context(picking_ids_not_to_backorder=delivery_picking.id).button_validate()
 
@@ -206,4 +207,4 @@ class TestReturnPicking(TestStockCommon):
             .with_context(active_ids=delivery_picking.ids, active_id=delivery_picking.ids[0],
             active_model='stock.picking'))
         stock_return_picking = stock_return_picking_form.save()
-        self.assertEqual(stock_return_picking.product_return_moves.quantity, 6)
+        self.assertEqual(stock_return_picking.product_return_moves.quantity, 0.01)

addons/stock/wizard/stock_picking_return.py

@@ -142,7 +142,7 @@ class ReturnPicking(models.TransientModel):
         for return_line in self.product_return_moves:
             if not return_line.move_id:
                 raise UserError(_("You have manually created product lines, please delete them to proceed."))
-            if not float_is_zero(return_line.quantity, return_line.uom_id.rounding):
+            if not float_is_zero(return_line.quantity, precision_rounding=return_line.uom_id.rounding):
                 returned_lines += 1
                 vals = self._prepare_move_default_values(return_line, new_picking)
                 r = return_line.move_id.copy(vals)