[FIX] account: tax in right refund account

Have a tax that has a different account for refunds
make an invoice and its refund

Before this commit, the refund's tax is still in the old account

After this commit, the refund's tax is in the account for refund defined on the tax

OPW 1907950

closes odoo/odoo#30325

addons/account/models/account_invoice.py

@@ -998,6 +998,21 @@ class AccountInvoice(models.Model):
             result.append((0, 0, values))
         return result
 
+    @api.model
+    def _refund_tax_lines_account_change(self, lines, taxes_to_change):
+        # Let's change the account on tax lines when
+        # @param {list} lines: a list of orm commands
+        # @param {dict} taxes_to_change
+        #   key: tax ID, value: refund account
+
+        if not taxes_to_change:
+            return lines
+
+        for line in lines:
+            if isinstance(line[2], dict) and line[2]['tax_id'] in taxes_to_change:
+                line[2]['account_id'] = taxes_to_change[line[2]['tax_id']]
+        return lines
+
     def _get_refund_common_fields(self):
         return ['partner_id', 'payment_term_id', 'account_id', 'currency_id', 'journal_id']
 
@@ -1039,7 +1054,12 @@ class AccountInvoice(models.Model):
         values['invoice_line_ids'] = self._refund_cleanup_lines(invoice.invoice_line_ids)
 
         tax_lines = invoice.tax_line_ids
-        values['tax_line_ids'] = self._refund_cleanup_lines(tax_lines)
+        taxes_to_change = {
+            line.tax_id.id: line.tax_id.refund_account_id.id
+            for line in tax_lines.filtered(lambda l: l.tax_id.refund_account_id != l.tax_id.account_id)
+        }
+        cleaned_tax_lines = self._refund_cleanup_lines(tax_lines)
+        values['tax_line_ids'] = self._refund_tax_lines_account_change(cleaned_tax_lines, taxes_to_change)
 
         if journal_id:
             journal = self.env['account.journal'].browse(journal_id)

addons/account/tests/test_account_customer_invoice.py

@@ -170,3 +170,59 @@ class TestAccountCustomerInvoice(AccountTestUsers):
         ))
 
         self.assertEquals(invoice.amount_untaxed, sum([x.base for x in invoice.tax_line_ids]))
+
+    def test_customer_invoice_tax_refund(self):
+        company = self.env.user.company_id
+        tax_account = self.env['account.account'].create({
+            'name': 'TAX',
+            'code': 'TAX',
+            'user_type_id': self.env.ref('account.data_account_type_current_assets').id,
+            'company_id': company.id,
+        })
+
+        tax_refund_account = self.env['account.account'].create({
+            'name': 'TAX_REFUND',
+            'code': 'TAX_R',
+            'user_type_id': self.env.ref('account.data_account_type_current_assets').id,
+            'company_id': company.id,
+        })
+
+        journalrec = self.env['account.journal'].search([('type', '=', 'sale')])[0]
+        partner3 = self.env.ref('base.res_partner_3')
+        account_id = self.env['account.account'].search([('user_type_id', '=', self.env.ref('account.data_account_type_revenue').id)], limit=1).id
+
+        tax = self.env['account.tax'].create({
+            'name': 'Tax 15.0',
+            'amount': 15.0,
+            'amount_type': 'percent',
+            'type_tax_use': 'sale',
+            'account_id': tax_account.id,
+            'refund_account_id': tax_refund_account.id
+        })
+
+        invoice_line_data = [
+            (0, 0,
+                {
+                    'product_id': self.env.ref('product.product_product_1').id,
+                    'quantity': 40.0,
+                    'account_id': account_id,
+                    'name': 'product test 1',
+                    'discount': 10.00,
+                    'price_unit': 2.27,
+                    'invoice_line_tax_ids': [(6, 0, [tax.id])],
+                }
+             )]
+
+        invoice = self.env['account.invoice'].create(dict(
+            name="Test Customer Invoice",
+            reference_type="none",
+            journal_id=journalrec.id,
+            partner_id=partner3.id,
+            invoice_line_ids=invoice_line_data
+        ))
+
+        invoice.action_invoice_open()
+
+        refund = invoice.refund()
+        self.assertEqual(invoice.tax_line_ids.mapped('account_id'), tax_account)
+        self.assertEqual(refund.tax_line_ids.mapped('account_id'), tax_refund_account)