[FIX] l10n_es_aeat_sii_oca: Merge dicts when no breakdown

After not doing breakdown, a problem has been discovered if there are
2 taxes of the same percentage, like 21% services and 21% goods.

For solving it, we move the `_merge_tax_dict` auxiliar method to the
mixin, and using it for the out taxes dictionary generation.

It includes an extra JSON file for tests for exercizing the problem.

Author: pedrobaeza

l10n_es_aeat_sii_oca/models/account_move.py

@@ -220,16 +220,6 @@ def _get_tax_info(self):
         # Use the method at l10n_es_aeat that returns the needed info
         return self._get_aeat_tax_info()
 
-    @api.model
-    def _merge_tax_dict(self, vat_list, tax_dict, comp_key, merge_keys):
-        """Helper method for merging values in an existing tax dictionary."""
-        for existing_dict in vat_list:
-            if existing_dict.get(comp_key, "-99") == tax_dict.get(comp_key, "-99"):
-                for key in merge_keys:
-                    existing_dict[key] += tax_dict[key]
-                return True
-        return False
-
     def _get_sii_in_taxes(self):
         """Get the taxes for purchase invoices.
 

l10n_es_aeat_sii_oca/models/sii_mixin.py

@@ -474,6 +474,16 @@ def _get_no_taxable_cause(self):
             or "ImporteTAIReglasLocalizacion"
         )
 
+    @api.model
+    def _merge_tax_dict(self, vat_list, tax_dict, comp_key, merge_keys):
+        """Helper method for merging values in an existing tax dictionary."""
+        for existing_dict in vat_list:
+            if existing_dict.get(comp_key, "-99") == tax_dict.get(comp_key, "-99"):
+                for key in merge_keys:
+                    existing_dict[key] += tax_dict[key]
+                return True
+        return False
+
     def _is_sii_type_breakdown_required(self):
         """Calculates if the block 'DesgloseTipoOperacion' is required for
         the invoice communication."""
@@ -565,9 +575,15 @@ def _get_sii_out_taxes(self):  # noqa: C901
                         is_s3 = not_ex_type == "S2"
                     if is_s3:
                         sub_dict["NoExenta"]["TipoNoExenta"] = "S3"
-                    sub_dict["NoExenta"]["DesgloseIVA"]["DetalleIVA"].append(
-                        self._get_sii_tax_dict(tax_line, tax_lines),
-                    )
+                    sub = sub_dict["NoExenta"]["DesgloseIVA"]["DetalleIVA"]
+                    tax_dict = self._get_sii_tax_dict(tax_line, tax_lines)
+                    if not self._merge_tax_dict(
+                        sub,
+                        tax_dict,
+                        "TipoImpositivo",
+                        ["BaseImponible", "CuotaRepercutida"],
+                    ):
+                        sub.append(tax_dict)
             # No sujetas
             if tax in taxes_sfens:
                 # ImporteTAIReglasLocalizacion or ImportePorArticulos7_14_Otros
@@ -598,7 +614,14 @@ def _get_sii_out_taxes(self):  # noqa: C901
                         {"TipoNoExenta": "S1", "DesgloseIVA": {"DetalleIVA": []}},
                     )
                     sub = not_exempt["DesgloseIVA"]["DetalleIVA"]
-                    sub.append(self._get_sii_tax_dict(tax_line, tax_lines))
+                    tax_dict = self._get_sii_tax_dict(tax_line, tax_lines)
+                    if not self._merge_tax_dict(
+                        sub,
+                        tax_dict,
+                        "TipoImpositivo",
+                        ["BaseImponible", "CuotaRepercutida"],
+                    ):
+                        sub.append(tax_dict)
                 if tax in taxes_sfesns:
                     default_no_taxable_cause = self._get_no_taxable_cause()
                     nsub_dict = service_breakdown.setdefault(

l10n_es_aeat_sii_oca/tests/json/sii_out_invoice_s_iva21b_s_iva21s_dict.json

@@ -0,0 +1,33 @@
+{
+  "IDFactura": {
+    "IDEmisorFactura": {"NIF": "U2687761C"},
+    "NumSerieFacturaEmisor": "TEST001",
+    "FechaExpedicionFacturaEmisor": "01-01-2020"
+  },
+  "PeriodoLiquidacion": {"Ejercicio": 2020, "Periodo": "01"},
+  "FacturaExpedida": {
+    "TipoFactura": "F1",
+    "ClaveRegimenEspecialOTrascendencia": "01",
+    "DescripcionOperacion": "/",
+    "TipoDesglose": {
+      "DesgloseFactura": {
+        "Sujeta": {
+          "NoExenta": {
+            "TipoNoExenta": "S1",
+            "DesgloseIVA": {
+              "DetalleIVA": [
+                {
+                  "TipoImpositivo": "21.0",
+                  "BaseImponible": 300.0,
+                  "CuotaRepercutida": 63.0
+                }
+              ]
+            }
+          }
+        }
+      }
+    },
+    "ImporteTotal": 363.0,
+    "Contraparte": {"NombreRazon": "Test partner", "NIF": "F35999705"}
+  }
+}

l10n_es_aeat_sii_oca/tests/test_l10n_es_aeat_sii.py

@@ -247,6 +247,7 @@ def test_partner_sii_enabled(self):
 
     def test_get_invoice_data(self):
         mapping = [
+            ("out_invoice", [(100, ["s_iva21b"]), (200, ["s_iva21s"])], {}, False),
             ("out_invoice", [(100, ["s_iva10b"]), (200, ["s_iva21s"])], {}, False),
             ("out_invoice", [(100, ["s_iva10b"]), (200, ["s_iva0_ns"])], {}, False),
             (