[IMP] l10n_es_aeat: Add country ISO code mapper function

Fulfills the need (seen in l10n_es_aeat_mod369) to obtain the ISO code of a country based on the country code stored in Odoo. It is an inverse function of _map_aeat_country_code.

l10n_es_aeat/models/res_partner.py

@@ -50,6 +50,12 @@ def _map_aeat_country_code(self, country_code, extended=False):
             country_code_map.update({"RE": "FR", "GP": "FR", "MQ": "FR", "GF": "FR"})
         return country_code_map.get(country_code, country_code)
 
+    def _map_aeat_country_iso_code(self, country_id):
+        """Map country ISO code according to AEAT code"""
+        code = country_id.code
+        country_iso_code_map = {"GR": "EL"}
+        return country_iso_code_map.get(code, code)
+
     @ormcache("self.env")
     def _get_aeat_europe_codes(self):
         europe = self.env.ref("base.europe", raise_if_not_found=False)

l10n_es_aeat/tests/test_l10n_es_aeat.py

@@ -109,3 +109,17 @@ def test_unique_date_range(self):
             self.env["l10n.es.aeat.map.tax"].create(
                 {"date_to": "2021-01-01", "model": 303}
             )
+
+    def test_map_aeat_iso_code_greece(self):
+        res_partner_obj = self.env["res.partner"]
+        greece_country = self.env.ref("base.gr")
+        iso_code = "EL"
+        mapping_return = res_partner_obj._map_aeat_country_iso_code(greece_country)
+        self.assertEqual(iso_code, mapping_return)
+
+    def test_map_aeat_iso_code_no_mapping(self):
+        res_partner_obj = self.env["res.partner"]
+        spain_country = self.env.ref("base.es")
+        iso_code = "ES"
+        mapping_return = res_partner_obj._map_aeat_country_iso_code(spain_country)
+        self.assertEqual(iso_code, mapping_return)