Refs #99 -- Improve support for currencies with less than 2 decimal places (#783)

* Refs #99 -- Fix stripe support for zero-decimal currencies

* Add new money formatting method

* Force decimal places in many places

* Locale-aware currency rendering

* Fix currencies in more places

* More currency fixes

src/pretix/base/services/orders.py

@@ -17,7 +17,7 @@ from django.utils.timezone import make_aware, now
 from django.utils.translation import ugettext as _
 
 from pretix.base.i18n import (
-    LazyDate, LazyLocaleException, LazyNumber, language,
+    LazyCurrencyNumber, LazyDate, LazyLocaleException, LazyNumber, language,
 )
 from pretix.base.models import (
     CartPosition, Event, Item, ItemVariation, Order, OrderPosition, Quota,
@@ -504,6 +504,8 @@ def _create_order(event: Event, email: str, positions: List[CartPosition], now_d
         for fee in fees:
             fee.order = order
             fee._calculate_tax()
+            if not fee.tax_rule.pk:
+                fee.tax_rule = None  # TODO: deprecate
             fee.save()
 
         OrderPosition.transform_cart_positions(positions, order)
@@ -568,6 +570,7 @@ def _perform_order(event: str, payment_provider: str, position_ids: List[str],
         email_context = {
             'total': LazyNumber(order.total),
             'currency': event.currency,
+            'total_with_currency': LazyCurrencyNumber(order.total, event.currency),
             'date': LazyDate(order.expires),
             'event': event.name,
             'url': build_absolute_uri(event, 'presale:event.order', kwargs={

src/pretix/base/services/pricing.py

@@ -1,5 +1,6 @@
 from decimal import Decimal
 
+from pretix.base.decimal import round_decimal
 from pretix.base.models import (
     AbstractPosition, InvoiceAddress, Item, ItemAddOn, ItemVariation, Voucher,
 )
@@ -59,4 +60,8 @@ def get_price(item: Item, variation: ItemVariation = None,
         price.gross = price.net
         price.name = ''
 
+    price.gross = round_decimal(price.gross, item.event.currency)
+    price.net = round_decimal(price.net, item.event.currency)
+    price.tax = price.gross - price.net
+
     return price