[FIX] account: remove no longer applicable tax lines

Porting the tests from commit b501105d9d0b08395b993bcae1957ee5a1a1fb23
(the behavior was already correct on version 14.0)

Note:
- also added unit test for the use case of 226a1155124e890d00e33968feb43b9fd6b99fa5

opw-2371745

closes odoo/odoo#62688

X-original-commit: 902d2d9a91f9a1167fd1f51ad71c021cc1e6bfc1
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>
Signed-off-by: Nicolas Galler <ngaller@users.noreply.github.com>

addons/account/tests/test_invoice_taxes.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from odoo import fields
 from odoo.addons.account.tests.common import AccountTestInvoicingCommon
 from odoo.tests import tagged, Form
 
@@ -540,3 +541,54 @@ class TestInvoiceTaxes(AccountTestInvoicingCommon):
             (50, self.percent_tax_3_incl),
         ], currency_id=self.currency_data['currency'], invoice_payment_term_id=self.pay_terms_a)
         invoice.action_post()
+
+    def test_changing_tax_to_caba_after_create_invoice(self):
+        tax_waiting_account = self.env['account.account'].create({
+            'name': 'TAX_WAIT',
+            'code': 'TWAIT',
+            'user_type_id': self.env.ref('account.data_account_type_current_liabilities').id,
+            'reconcile': True,
+            'company_id': self.company_data['company'].id,
+        })
+        sale_tax = self.company_data['default_tax_sale']
+        invoice = self._create_invoice([
+            (100, sale_tax),
+        ])
+        # turn on cash basis on the same tax that was used
+        self.company_data['company'].tax_exigibility = True
+        sale_tax.write({
+            'tax_exigibility': 'on_payment',
+            'cash_basis_transition_account_id': tax_waiting_account.id,
+        })
+        invoice.action_post()
+
+        tax_lines = invoice.line_ids.filtered('tax_line_id')
+        self.assertEqual(len(tax_lines), 1, 'Should have only 1 tax line')
+        self.assertNotEqual(tax_lines.price_unit, 0.0)
+        self.assertEqual(tax_lines.tax_base_amount, 100.0)
+        self.assertEqual(tax_lines.account_id.name, 'TAX_WAIT')
+
+    def test_recompute_tax_when_change_currency(self):
+        """
+        - In a multi currency company, create an invoice with the domestic
+          currency ($);
+        - Add a product (100$) with taxes;
+        -  Change the currency to a foreign one (€);
+        - The product don't change of amount but only of currency (500€);
+        - Save the invoice, and print it.
+        """
+        invoice = self._create_invoice([
+            (100, self.percent_tax_1),
+        ])
+        tax_line = invoice.line_ids.filtered('tax_line_id')
+        self.env['res.currency.rate'].create({
+            'name': fields.Date.to_string(fields.Date.today()),
+            'rate': 4.0,
+            'currency_id': self.currency_data['currency'].id,
+            'company_id': self.env.company.id,
+        })
+        with Form(invoice) as invoice_form:
+            invoice_form.currency_id = self.currency_data['currency']
+
+        self.assertEqual(tax_line.tax_base_amount, 25, 'Should convert tax base amount to company currency')
+        self.assertEqual(tax_line.balance, -5.25, 'Should convert balance to company currency')