Add unit tests for when CAS_FEDERATE is True

Also fix some unicode related bugs

cas_server/management/commands/cas_clean_federate.py

@@ -1,11 +1,7 @@
 from django.core.management.base import BaseCommand
 from django.utils.translation import ugettext_lazy as _
-from django.utils import timezone
-
-from datetime import timedelta
 
 from ... import models
-from ...default_settings import settings
 
 
 class Command(BaseCommand):
@@ -13,11 +9,5 @@ class Command(BaseCommand):
     help = _(u"Clean old federated users")
 
     def handle(self, *args, **options):
-        federated_users = models.FederatedUser.objects.filter(
-            last_update__lt=(timezone.now() - timedelta(seconds=settings.CAS_TICKET_TIMEOUT))
-        )
-        known_users = {user.username for user in models.User.objects.all()}
-        for user in federated_users:
-            if not ('%s@%s' % (user.username, user.provider)) in known_users:
-                user.delete()
+        models.FederatedUser.clean_old_entries()
         models.FederateSLO.clean_deleted_sessions()