Correct english typos (#662)

* Check that vouchers selected via API are for the correct event

* Choose different subject for reminder mails if auto-expiry is off

* correct english typos

As with PR #660, it should be checked whether the changes to the
.po-files are respected in the corresponding src-files.

src/tests/api/test_vouchers.py

@@ -4,8 +4,9 @@ from decimal import Decimal
 import pytest
 from django.utils import timezone
 from django.utils.timezone import now
+from pytz import UTC
 
-from pretix.base.models import Voucher
+from pretix.base.models import Event, Voucher
 
 
 @pytest.fixture
@@ -541,6 +542,28 @@ def change_voucher(token_client, organizer, event, voucher, data, expected_failu
     voucher.refresh_from_db()
 
 
+@pytest.mark.django_db
+def test_change_to_item_of_other_event(token_client, organizer, event, item):
+    e2 = Event.objects.create(
+        organizer=organizer,
+        name='Dummy2',
+        slug='dummy2',
+        date_from=datetime.datetime(2017, 12, 27, 10, 0, 0, tzinfo=UTC),
+        plugins='pretix.plugins.banktransfer,pretix.plugins.ticketoutputpdf'
+    )
+    ticket2 = e2.items.create(name='Late-bird ticket', default_price=23)
+    v = event.vouchers.create(item=item)
+    change_voucher(
+        token_client, organizer, event, v,
+        data={
+            'item': ticket2.pk
+        },
+        expected_failure=True
+    )
+    v.refresh_from_db()
+    assert v.item == item
+
+
 @pytest.mark.django_db
 def test_change_non_blocking_voucher(token_client, organizer, event, item, quota):
     v = event.vouchers.create(item=item)