[FIX] sale: _get_tax_amount_by_group

When computing the amount tax by group, the taxes which affect base of
subsequent taxes must be taken into account and added to the base amount for
only one product.

opw:703524

addons/sale/models/sale.py

@@ -505,7 +505,7 @@ class SaleOrder(models.Model):
                 amount = tax.compute_all(line.price_reduce + base_tax, quantity=line.product_uom_qty)['taxes'][0]['amount']
                 res[group] += amount
                 if tax.include_base_amount:
-                    base_tax += amount
+                    base_tax += tax.compute_all(line.price_reduce + base_tax, quantity=1)['taxes'][0]['amount']
         res = sorted(res.items(), key=lambda l: l[0].sequence)
         res = map(lambda l: (l[0].name, l[1]), res)
         return res