UPD: more/better tests.

dav_events/tests/generic.py

@@ -0,0 +1,22 @@
+from django.apps import apps
+from django.contrib.auth import get_user_model
+from django.contrib.auth.models import Group
+
+
+class RoleMixin(object):
+    def create_user_for_role(self, role_name, password, first_name, last_name):
+        group = Group(name=role_name)
+        group.save()
+
+        user_model = get_user_model()
+        email = '{}@localhost'.format(role_name)
+        user_name = email
+        user = user_model.objects.create_user(username=user_name, password=password, email=user_name,
+                                              first_name=first_name, last_name=last_name)
+        user.groups.add(group)
+
+        setting_name = 'groups_{}'.format(role_name)
+        app_config = apps.get_app_config('dav_events')
+        setattr(app_config.settings, setting_name, [role_name])
+
+        return user