[FIX] sale: set a default qty_delivered on new sol

Steps to reproduce:

- Create an SO with an SOL and save the record.

** The `qty_delivered` of that SOL will be null in the DB. **

Cause of the issue:

Since the `qty_delivered` field is computed, the default value is set in
the DB comes from the `_compute_qty_delivered` method at record creation
However, no default value is set here when the `qty_delivered_method` is
not `'analytic'`.

Note:

In 15.0, a default value was set because of these lines:
https://github.com/odoo/odoo/blob/313418804ae5cb6a786488ffc174b8eebffb796e/addons/sale/models/sale_order_line.py#L350-L353
These were removed by this commit de4911a.

opw-3771589

closes odoo/odoo#163180

X-original-commit: 3e20e293771a252bbdcd395b5a12a2cef70f0218
Signed-off-by: William Henrotin (whe) <whe@odoo.com>

addons/sale/models/sale_order_line.py

@@ -207,6 +207,7 @@ class SaleOrderLine(models.Model):
     qty_delivered = fields.Float(
         string="Delivery Quantity",
         compute='_compute_qty_delivered',
+        default=0.0,
         digits='Product Unit of Measure',
         store=True, readonly=False, copy=False)
 

addons/sale/tests/test_sale_order.py

@@ -746,3 +746,16 @@ class TestSalesTeam(SaleCommon):
         self.assertEqual(sale_order.team_id, crm_team0, "Sales team should change to partner's")
         sale_order.with_user(self.user_not_in_team).write({'partner_id': partner_b.id})
         self.assertEqual(sale_order.team_id, crm_team1, "Sales team should change to partner's")
+
+    def test_qty_delivered_on_creation(self):
+        """Checks that the qty delivered of sol is automatically set to 0.0 when an so is created"""
+        sale_order = self.env['sale.order'].create({
+            'partner_id': self.partner.id,
+            'order_line': [
+                Command.create({
+                    'product_id': self.product.id,
+                })],
+        })
+        # As we want to determine if the value is set in the DB we need to perform a search
+        self.assertFalse(self.env['sale.order.line'].search(['&', ('order_id', '=', sale_order.id), ('qty_delivered', '=', False)]))
+        self.assertEqual(self.env['sale.order.line'].search(['&', ('order_id', '=', sale_order.id), ('qty_delivered', '=', 0.0)]), sale_order.order_line)