diff --git a/swh/vault/tests/conftest.py b/swh/vault/tests/conftest.py
index 27f4864..ca4aab8 100644
--- a/swh/vault/tests/conftest.py
+++ b/swh/vault/tests/conftest.py
@@ -1,80 +1,82 @@
 import pytest
 import glob
 import os
 import pkg_resources.extern.packaging.version
 
 from swh.core.utils import numfile_sortkey as sortkey
 from swh.vault import get_vault
 from swh.vault.tests import SQL_DIR
 from swh.storage.tests import SQL_DIR as STORAGE_SQL_DIR
 from pytest_postgresql import factories
 
 
+os.environ['LC_ALL'] = 'C.UTF-8'
+
 pytest_v = pkg_resources.get_distribution("pytest").parsed_version
 if pytest_v < pkg_resources.extern.packaging.version.parse('3.9'):
     @pytest.fixture
     def tmp_path(request):
         import tempfile
         import pathlib
         with tempfile.TemporaryDirectory() as tmpdir:
             yield pathlib.Path(tmpdir)
 
 
 def db_url(name, postgresql_proc):
     return 'postgresql://{user}@{host}:{port}/{dbname}'.format(
         host=postgresql_proc.host,
         port=postgresql_proc.port,
         user='postgres',
         dbname=name)
 
 
 postgresql2 = factories.postgresql('postgresql_proc', 'tests2')
 
 
 @pytest.fixture
 def swh_vault(request, postgresql_proc, postgresql, postgresql2, tmp_path):
 
     for sql_dir, pg in ((SQL_DIR, postgresql), (STORAGE_SQL_DIR, postgresql2)):
         dump_files = os.path.join(sql_dir, '*.sql')
         all_dump_files = sorted(glob.glob(dump_files), key=sortkey)
 
         cursor = pg.cursor()
         for fname in all_dump_files:
             with open(fname) as fobj:
                 # disable concurrent index creation since we run in a
                 # transaction
                 cursor.execute(fobj.read().replace('concurrently', ''))
         pg.commit()
 
     vault_config = {
         'db': db_url('tests', postgresql_proc),
         'storage': {
             'cls': 'local',
             'args': {
                 'db': db_url('tests2', postgresql_proc),
                 'objstorage': {
                     'cls': 'pathslicing',
                     'args': {
                         'root': str(tmp_path),
                         'slicing': '0:1/1:5',
                     },
                 },
             },
         },
         'cache': {
             'cls': 'pathslicing',
             'args': {
                 'root': str(tmp_path),
                 'slicing': '0:1/1:5',
                 'allow_delete': True,
             }
         },
         'scheduler': {
             'cls': 'remote',
             'args': {
                 'url': 'http://swh-scheduler:5008',
             },
         },
     }
 
     return get_vault('local', vault_config)