diff --git a/swh/lister/cli.py b/swh/lister/cli.py
--- a/swh/lister/cli.py
+++ b/swh/lister/cli.py
@@ -63,8 +63,9 @@
     if not config_file:
         config_file = os.environ.get('SWH_CONFIG_FILENAME')
     conf = config.read(config_file, override_conf)
+    if not conf:
+        conf = override_conf
     ctx.obj['config'] = conf
-    ctx.obj['override_conf'] = override_conf
 
 
 @lister.command(name='db-init', context_settings=CONTEXT_SETTINGS)
diff --git a/swh/lister/core/models.py b/swh/lister/core/models.py
--- a/swh/lister/core/models.py
+++ b/swh/lister/core/models.py
@@ -71,7 +71,6 @@
         drop_tables (bool): if True, tables will be dropped before
             (re)creating them.
     """
-
     if drop_tables:
         logger.info('Dropping tables')
         SQLBase.metadata.drop_all(db_engine, checkfirst=True)
diff --git a/swh/lister/debian/__init__.py b/swh/lister/debian/__init__.py
--- a/swh/lister/debian/__init__.py
+++ b/swh/lister/debian/__init__.py
@@ -6,7 +6,7 @@
 from typing import Any, List, Mapping
 
 
-def debian_init(db_engine, lister=None,
+def debian_init(db_engine,
                 override_conf: Mapping[str, Any] = {},
                 distributions: List[str] = ['stretch', 'buster'],
                 area_names: List[str] = ['main', 'contrib', 'non-free']):
@@ -14,7 +14,6 @@
 
     Args:
         db_engine: SQLAlchemy manipulation database object
-        lister: Debian lister instance. None by default.
         override_conf: Override conf to pass to instantiate a lister
         distributions: Default distribution to build
 
@@ -22,32 +21,29 @@
     """
     distribution_name = 'Debian'
     from swh.lister.debian.models import Distribution, Area
+    from sqlalchemy.orm import sessionmaker
+    db_session = sessionmaker(bind=db_engine)()
+
+    existing_distrib = db_session \
+        .query(Distribution) \
+        .filter(Distribution.name == distribution_name) \
+        .one_or_none()
+    if not existing_distrib:
+        distrib = Distribution(name=distribution_name,
+                               type='deb',
+                               mirror_uri='http://deb.debian.org/debian/')
+        db_session.add(distrib)
 
-    if lister is None:
-        from .lister import DebianLister
-        lister = DebianLister(distribution=distribution_name,
-                              override_config=override_conf)
-
-    if not lister.db_session\
-                 .query(Distribution)\
-                 .filter(Distribution.name == distribution_name)\
-                 .one_or_none():
-
-        d = Distribution(
-            name=distribution_name,
-            type='deb',
-            mirror_uri='http://deb.debian.org/debian/')
-        lister.db_session.add(d)
-
-        areas = []
         for distribution_name in distributions:
             for area_name in area_names:
-                areas.append(Area(
+                area = Area(
                     name='%s/%s' % (distribution_name, area_name),
-                    distribution=d,
-                ))
-        lister.db_session.add_all(areas)
-        lister.db_session.commit()
+                    distribution=distrib,
+                )
+                db_session.add(area)
+
+        db_session.commit()
+    db_session.close()
 
 
 def register() -> Mapping[str, Any]:
diff --git a/swh/lister/debian/tests/conftest.py b/swh/lister/debian/tests/conftest.py
--- a/swh/lister/debian/tests/conftest.py
+++ b/swh/lister/debian/tests/conftest.py
@@ -15,7 +15,7 @@
     lister = swh_listers['debian']
 
     # Initialize the debian data model
-    debian_init(lister.db_engine, lister=lister,
+    debian_init(lister.db_engine,
                 distributions=['stretch'],
                 area_names=['main', 'contrib'])
 
diff --git a/swh/lister/tests/test_cli.py b/swh/lister/tests/test_cli.py
--- a/swh/lister/tests/test_cli.py
+++ b/swh/lister/tests/test_cli.py
@@ -98,21 +98,22 @@
 
 
 def test_task_types(swh_scheduler_config, tmp_path):
-    db_url = init_db().url()
-
     configfile = tmp_path / 'config.yml'
-    configfile.write_text(yaml.dump({'scheduler': {
-        'cls': 'local',
-        'args': swh_scheduler_config}}))
+    config = {
+        'scheduler': {
+            'cls': 'local',
+            'args': swh_scheduler_config
+        }
+    }
+    configfile.write_text(yaml.dump(config))
     runner = CliRunner()
     result = runner.invoke(cli, [
-        '--db-url', db_url,
         '--config-file', configfile.as_posix(),
         'register-task-types'])
 
     assert result.exit_code == 0, traceback.print_exception(*result.exc_info)
 
-    scheduler = get_scheduler(cls='local', args=swh_scheduler_config)
+    scheduler = get_scheduler(**config['scheduler'])
     all_tasks = [
         'list-bitbucket-full', 'list-bitbucket-incremental',
         'list-cran',
@@ -125,7 +126,7 @@
         'list-phabricator-full',
         'list-packagist',
         'list-pypi',
-        ]
+    ]
     for task in all_tasks:
         task_type_desc = scheduler.get_task_type(task)
         assert task_type_desc