Order creation API: Add support for reverse charge

doc/api/resources/orders.rst

@@ -747,8 +747,6 @@ Creating orders
        * does not allow to pass data to plugins and will therefore cause issues with some plugins like the shipping
          module
 
-       * does not support reverse charge taxation
-
        * does not support file upload questions
 
    You can supply the following fields of the resource:
@@ -789,6 +787,9 @@ Creating orders
       * ``state``
       * ``internal_reference``
       * ``vat_id``
+      * ``vat_id_validated`` (optional) – If you need support for reverse charge (rarely the case), you need to check
+       yourself if the passed VAT ID is a valid EU VAT ID. In that case, set this to ``true``. Only valid VAT IDs will
+       trigger reverse charge taxation. Don't forget to set ``is_business`` as well!
 
    * ``positions``
 
@@ -881,7 +882,7 @@ Creating orders
             ],
             "subevent": null
           }
-        ],
+        ]
       }
 
    **Example response**:

src/pretix/api/serializers/order.py

@@ -49,7 +49,7 @@ class InvoiceAddressSerializer(I18nAwareModelSerializer):
         model = InvoiceAddress
         fields = ('last_modified', 'is_business', 'company', 'name', 'name_parts', 'street', 'zipcode', 'city', 'country',
                   'state', 'vat_id', 'vat_id_validated', 'internal_reference')
-        read_only_fields = ('last_modified', 'vat_id_validated')
+        read_only_fields = ('last_modified',)
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -377,7 +377,7 @@ class OrderSerializer(I18nAwareModelSerializer):
                     }
                 try:
                     ia = instance.invoice_address
-                    if iadata.get('vat_id') != ia.vat_id:
+                    if iadata.get('vat_id') != ia.vat_id and 'vat_id_validated' not in iadata:
                         ia.vat_id_validated = False
                     self.fields['invoice_address'].update(ia, iadata)
                 except InvoiceAddress.DoesNotExist:

src/tests/api/test_orders.py

@@ -2889,6 +2889,64 @@ def test_order_create_auto_pricing(token_client, organizer, event, item, quota,
     assert o.total == item.default_price + Decimal('0.25')
 
 
+@pytest.mark.django_db
+def test_order_create_auto_pricing_reverse_charge(token_client, organizer, event, item, quota, question, taxrule):
+    taxrule.eu_reverse_charge = True
+    taxrule.home_country = Country('DE')
+    taxrule.save()
+    item.tax_rule = taxrule
+    item.save()
+    res = copy.deepcopy(ORDER_CREATE_PAYLOAD)
+    res['positions'][0]['item'] = item.pk
+    res['positions'][0]['answers'][0]['question'] = question.pk
+    res['invoice_address']['country'] = 'FR'
+    res['invoice_address']['is_business'] = True
+    res['invoice_address']['vat_id'] = 'FR12345'
+    res['invoice_address']['vat_id_validated'] = True
+    del res['positions'][0]['price']
+    resp = token_client.post(
+        '/api/v1/organizers/{}/events/{}/orders/'.format(
+            organizer.slug, event.slug
+        ), format='json', data=res
+    )
+    assert resp.status_code == 201
+    with scopes_disabled():
+        o = Order.objects.get(code=resp.data['code'])
+        p = o.positions.first()
+    assert p.price == Decimal('19.33')
+    assert p.tax_rate == Decimal('0.00')
+    assert p.tax_value == Decimal('0.00')
+    assert o.total == Decimal('19.58')
+
+
+@pytest.mark.django_db
+def test_order_create_auto_pricing_reverse_charge_require_valid_vatid(token_client, organizer, event, item, quota,
+                                                                      question, taxrule):
+    taxrule.eu_reverse_charge = True
+    taxrule.home_country = Country('DE')
+    taxrule.save()
+    item.tax_rule = taxrule
+    item.save()
+    res = copy.deepcopy(ORDER_CREATE_PAYLOAD)
+    res['positions'][0]['item'] = item.pk
+    res['positions'][0]['answers'][0]['question'] = question.pk
+    res['invoice_address']['country'] = 'FR'
+    res['invoice_address']['is_business'] = True
+    res['invoice_address']['vat_id'] = 'FR12345'
+    del res['positions'][0]['price']
+    resp = token_client.post(
+        '/api/v1/organizers/{}/events/{}/orders/'.format(
+            organizer.slug, event.slug
+        ), format='json', data=res
+    )
+    assert resp.status_code == 201
+    with scopes_disabled():
+        o = Order.objects.get(code=resp.data['code'])
+        p = o.positions.first()
+    assert p.price == Decimal('23.00')
+    assert p.tax_rate == Decimal('19.00')
+
+
 @pytest.mark.django_db
 def test_order_create_voucher_price(token_client, organizer, event, item, quota, question):
     res = copy.deepcopy(ORDER_CREATE_PAYLOAD)
@@ -3391,6 +3449,34 @@ def test_order_update_allowed_fields(token_client, organizer, event, order):
         assert order.all_logentries().get(action_type='pretix.event.order.modified')
 
 
+@pytest.mark.django_db
+def test_order_update_validated_vat_id(token_client, organizer, event, order):
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/orders/{}/'.format(
+            organizer.slug, event.slug, order.code
+        ), format='json', data={
+            'invoice_address': {
+                "is_business": False,
+                "company": "This is my company name",
+                "name": "John Doe",
+                "name_parts": {},
+                "street": "",
+                "state": "",
+                "zipcode": "",
+                "city": "Paris",
+                "country": "FR",
+                "internal_reference": "",
+                "vat_id": "FR123",
+                "vat_id_validated": True
+            }
+        }
+    )
+    assert resp.status_code == 200
+    order.refresh_from_db()
+    assert order.invoice_address.vat_id == "FR123"
+    assert order.invoice_address.vat_id_validated
+
+
 @pytest.mark.django_db
 def test_order_update_invoiceaddress_delete_create(token_client, organizer, event, order):
     event.settings.locales = ['de', 'en']