Impacted versions:
11.0

I don't know if it is an issue, but I think is strange.

`product_qty` is in unit of `product` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L240
`reserved_availability` is in unit of `stock.move` : https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L295

`move.product_qty - move.reserved_availability` seems to have no sens, no ?

https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L915
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L917
https://github.com/odoo/odoo/blob/11.0/addons/stock/models/stock_move.py#L924

thank for your answer

@jco-odoo 
@alnslang 


self.assertEqual(move_line_pack_cust.product_uom_id.id, self.uom_unit.id)
        
        backorder = self.env['stock.picking'].search([('backorder_id', '=', picking_stock_pack.id)])
        backorder.move_lines.write({'move_line_ids': [(0, 0, {
            'product_id': self.product1.id,
            'product_uom_id': self.uom_dozen.id,
            'qty_done': 1,
            'product_uom_qty': 0,
            'lot_id': False,
            'package_id': False,
            'result_package_id': False,
            'location_id': backorder.location_id.id,
            'location_dest_id': backorder.location_dest_id.id,
            'picking_id': backorder.id,
        })]})
        overprocessed_wizard_dict = backorder.button_validate()
        overprocessed_wizard = self.env[overprocessed_wizard_dict['res_model']].browse(overprocessed_wizard_dict['res_id'])
        overprocessed_wizard.action_confirm()
        backorder_move = backorder.move_lines
        self.assertEqual(backorder_move.state, 'done')
        self.assertEqual(backorder_move.quantity_done, 12.0)
        self.assertEqual(backorder_move.product_uom_qty, 12.0)
        self.assertEqual(backorder_move.product_uom, self.uom_unit)
        
        move_pack_cust._action_assign()
        self.assertEqual(move_pack_cust.state, 'assigned')
        self.assertEqual(move_line_pack_cust.product_uom_qty, 12)
        self.assertEqual(move_line_pack_cust.product_uom_id.id, self.uom_unit.id)
        self.assertEqual(self.env['stock.quant']._get_available_quantity(self.product1, move_stock_pack.location_dest_id), 6)
    def test_link_assign_8(self):