tests: mark concurrency test as slow

tests/test_concurrency.py

@@ -14,19 +14,20 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import threading
+
+import pytest
+
 from django.db import connection
 
 from authentic2.models import Attribute, AttributeValue
 
-import threading
-
 
+@pytest.mark.slow
 def test_attribute_value_uniqueness(migrations, transactional_db, simple_user, concurrency):
-    #from django.db.transaction import set_autocommit
-    # disabled default attributes
+    # disable default attributes
     Attribute.objects.update(disabled=True)
 
-    #set_autocommit(True)
     acount = Attribute.objects.count()
 
     single_at = Attribute.objects.create(