diff --git a/conftest.py b/conftest.py
index e9d27de..50822c3 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,73 +1,75 @@
 # Copyright (C) 2019-2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import os
 import pytest
 import yaml
 
 from typing import Any, Dict
 
 from swh.storage.tests.conftest import * # noqa
 from swh.scheduler.tests.conftest import *  # noqa
 
 
 @pytest.fixture
 def swh_loader_config(swh_storage_postgresql) -> Dict[str, Any]:
     return {
         'storage': {
             'cls': 'pipeline',
             'steps': [
                 {'cls': 'retry'},
+                {'cls': 'filter'},
+                {'cls': 'buffer'},
                 {
                     'cls': 'local',
                     'args': {
                         'db': swh_storage_postgresql.dsn,
                         'objstorage': {
                             'cls': 'memory',
                             'args': {}
                         },
                     }
                 }
             ]
         },
         'deposit': {
             'url': 'https://deposit.softwareheritage.org/1/private',
             'auth': {
                 'username': 'user',
                 'password': 'pass',
             }
         },
     }
 
 
 @pytest.fixture
 def swh_config(swh_loader_config, monkeypatch, tmp_path):
     conffile = os.path.join(str(tmp_path), 'loader.yml')
     with open(conffile, 'w') as f:
         f.write(yaml.dump(swh_loader_config))
     monkeypatch.setenv('SWH_CONFIG_FILENAME', conffile)
     return conffile
 
 
 @pytest.fixture(autouse=True, scope='session')
 def swh_proxy():
     """Automatically inject this fixture in all tests to ensure no outside
        connection takes place.
 
     """
     os.environ['http_proxy'] = 'http://localhost:999'
     os.environ['https_proxy'] = 'http://localhost:999'
 
 
 @pytest.fixture(scope='session')  # type: ignore  # expected redefinition
 def celery_includes():
     return [
         'swh.loader.package.archive.tasks',
         'swh.loader.package.cran.tasks',
         'swh.loader.package.debian.tasks',
         'swh.loader.package.deposit.tasks',
         'swh.loader.package.npm.tasks',
         'swh.loader.package.pypi.tasks',
     ]