Merge branch 'fix/registrations-renewal-start-date' into 'master'

Fix renewal since date calculation

See merge request !899

website/registrations/services.py

 """The services defined by the registrations package"""
 import string
 import unicodedata
-from datetime import timedelta
 
 from django.conf import settings
 from django.contrib.auth import get_user_model
@@ -265,7 +264,7 @@ def _create_membership_from_entry(entry, member=None):
                 if membership.until is None:
                     raise ValueError('This member already has a never ending '
                                      'membership')
-                since = membership.until + timedelta(days=1)
+                since = membership.until
         except Renewal.DoesNotExist:
             pass
         until = timezone.datetime(year=lecture_year + 1,

website/registrations/tests/test_services.py

@@ -403,7 +403,7 @@ class ServicesTest(TestCase):
             self.e3.length = Entry.MEMBERSHIP_YEAR
             membership3 = services._create_membership_from_entry(self.e3)
             self.assertEqual(membership3.since,
-                             existing_membership.until + timedelta(days=1))
+                             existing_membership.until)
             self.assertEqual(membership3.until, timezone.datetime(
                 year=2017, month=9, day=1).date())
             self.assertEqual(membership3.user, self.e3.member)