[FIX] account: tax included

- Create a tax included of 21 %
- Create a product sold 7.00, set the 21 % tax
- Add the product in a SO

Amount w/o tax: 5.79
Amount tax: 1.22
Total: 7.01

We defer the base rounding to the end of the method so that the rounding
doesn't impact the tax computation of included taxes.

Complement of 6e46ba7b460b5f155735c91f957a4dca3dec8f96

opw-777221

2 files changed, 24 insertions, 3 deletions

diff --git a/addons/account/models/account.py b/addons/account/models/account.py
index 4630ece0eeb..02ff42a09f3 100644
--- a/addons/account/models/account.py
+++ b/addons/account/models/account.py
@@ -758,7 +758,7 @@ class AccountTax(models.Model):
             # (145 - 15) / (1.0 + ((10 + 20) / 100.0)) = 130 / 1.3 = 100
             if fixed_amount == 0.0 and percent_amount == 0.0:
                 return base_amount
-            return round((base_amount - fixed_amount) / (1.0 + percent_amount / 100.0), prec)
+            return (base_amount - fixed_amount) / (1.0 + percent_amount / 100.0)
 
         base = round(price_unit * quantity, prec)
 
@@ -822,7 +822,7 @@ class AccountTax(models.Model):
                 'id': tax.id,
                 'name': tax.with_context(**{'lang': partner.lang} if partner else {}).name,
                 'amount': sign * tax_amount,
-                'base': sign * tax_base,
+                'base': round(sign * tax_base, prec),
                 'sequence': tax.sequence,
                 'account_id': tax.account_id.id,
                 'refund_account_id': tax.refund_account_id.id,
@@ -833,7 +833,7 @@ class AccountTax(models.Model):
             'taxes': taxes_vals,
             'total_excluded': sign * (currency.round(total_excluded) if round_total else total_excluded),
             'total_included': sign * (currency.round(total_included) if round_total else total_included),
-            'base': sign * base,
+            'base': round(sign * base, prec),
         }
 
     @api.v7
diff --git a/addons/account/tests/test_tax.py b/addons/account/tests/test_tax.py
index 5b6361bf69c..df12bb1dd3a 100644
--- a/addons/account/tests/test_tax.py
+++ b/addons/account/tests/test_tax.py
@@ -28,6 +28,12 @@ class TestTax(AccountTestUsers):
             'amount': 10,
             'sequence': 3,
         })
+        self.percent_tax_bis = self.tax_model.create({
+            'name': "Percent tax bis",
+            'amount_type': 'percent',
+            'amount': 21,
+            'sequence': 3,
+        })
         self.division_tax = self.tax_model.create({
             'name': "Division tax",
             'amount_type': 'division',
@@ -172,6 +178,21 @@ class TestTax(AccountTestUsers):
             ],
             res_percent
         )
+        self.percent_tax_bis.price_include = True
+        self.percent_tax_bis.include_base_amount = True
+        res_percent = self.percent_tax_bis.compute_all(7.0)
+        self._check_compute_all_results(
+            7.0,   # 'base'
+            7.0,   # 'total_included'
+            5.79,  # 'total_excluded'
+            [
+                # base , amount     | seq | amount | incl | incl_base
+                # ---------------------------------------------------
+                (5.79, 1.21),  # |  3  |    21% |   t  |     t
+                # ---------------------------------------------------
+            ],
+            res_percent
+        )
 
     def test_tax_sequence_normalized_set(self):
         self.division_tax.sequence = 1