TaxID: Expand API to allow retrieving or deleting a single TaxID

Creating and listing TaxID have been supported for a long time, but retrieving
or deleting a single TaxID wasn't implemented, so let's change that.

Stripe doc:
- https://stripe.com/docs/api/customer_tax_ids/retrieve
- https://stripe.com/docs/api/customer_tax_ids/delete

localstripe/resources.py

@@ -947,6 +947,29 @@ def _api_list_tax_ids(cls, id, **kwargs):
         obj = cls._api_retrieve(id)
         return obj.tax_ids
 
+    @classmethod
+    def _api_retrieve_tax_id(cls, id, tax_id, **kwargs):
+        if kwargs:
+            raise UserError(400, 'Unexpected ' + ', '.join(kwargs.keys()))
+
+        obj = cls._api_retrieve(id)
+        for txi in obj.tax_ids._list:
+            if txi.id == tax_id:
+                return txi
+        raise UserError(404, 'Customer ' + id + ' does not have a tax ID with '
+                             'ID ' + tax_id)
+
+    @classmethod
+    def _api_delete_tax_id(cls, id, tax_id, **kwargs):
+        if kwargs:
+            raise UserError(400, 'Unexpected ' + ', '.join(kwargs.keys()))
+
+        obj = cls._api_retrieve(id)
+        tax_id_obj = cls._api_retrieve_tax_id(id, tax_id)
+        obj.tax_ids._list.remove(tax_id_obj)
+
+        return DeletedObject(tax_id_obj.id, tax_id_obj.object)
+
     @classmethod
     def _api_list_subscriptions(cls, id, **kwargs):
         if kwargs:
@@ -1042,8 +1065,12 @@ def _api_update_subscription(cls, id, subscription_id, **data):
      Customer._api_update_subscription),
     # This is the old API route:
     ('POST', '/v1/customers/{id}/cards', Customer._api_add_source),
+    ('GET', '/v1/customers/{id}/tax_ids', Customer._api_list_tax_ids),
+    ('GET', '/v1/customers/{id}/tax_ids/{tax_id}',
+     Customer._api_retrieve_tax_id),
     ('POST', '/v1/customers/{id}/tax_ids', Customer._api_add_tax_id),
-    ('GET', '/v1/customers/{id}/tax_ids', Customer._api_list_tax_ids)))
+    ('DELETE', '/v1/customers/{id}/tax_ids/{tax_id}',
+     Customer._api_delete_tax_id)))
 
 
 class Event(StripeObject):

localstripe/server.py

@@ -261,6 +261,8 @@ async def f(request):
             data['source_id'] = request.match_info['source_id']
         if 'subscription_id' in request.match_info:
             data['subscription_id'] = request.match_info['subscription_id']
+        if 'tax_id' in request.match_info:
+            data['tax_id'] = request.match_info['tax_id']
         expand = data.pop('expand', None)
         return json_response(func(**data)._export(expand=expand))
     return f

test.sh

@@ -37,9 +37,15 @@ cus=$(curl -sSfg -u $SK: $HOST/v1/customers \
       | grep -oE 'cus_\w+' | head -n 1)
 
 curl -sSfg -u $SK: $HOST/v1/customers/$cus/tax_ids \
-     -d type=eu_vat -d value=DE123456789 \
+     -d type=eu_vat \
+     -d value=DE123456789 \
      -d expand[]=customer
 
+tax_id=$(curl -sSfg -u $SK: $HOST/v1/customers/$cus/tax_ids \
+              -d type=eu_vat \
+              -d value=BE00111222333 \
+         | grep -oE 'txi_\w+' | head -n 1)
+
 curl -sSfg -u $SK: $HOST/v1/customers/$cus?expand[]=tax_ids.data.customer
 
 curl -sSfg -u $SK: $HOST/v1/customers/$cus?expand[]=subscriptions.data.items.data
@@ -48,6 +54,14 @@ code=$(curl -sg -o /dev/null -w '%{http_code}' -u $SK: \
        $HOST/v1/customers/$cus?expand[]=subscriptions.data.items.data.tax_ids)
 [ "$code" -eq 400 ]
 
+curl -sSfg -u $SK: $HOST/v1/customers/$cus/tax_ids/$tax_id
+
+curl -sSfg -u $SK: -X DELETE $HOST/v1/customers/$cus/tax_ids/$tax_id
+
+code=$(curl -sg -o /dev/null -w '%{http_code}' -u $SK: \
+       $HOST/v1/customers/$cus/tax_ids/$tax_id)
+[ "$code" -eq 404 ]
+
 txr1=$(curl -sSfg -u $SK: $HOST/v1/tax_rates \
             -d display_name=VAT \
             -d description='TVA France taux normal' \