diff --git a/conftest.py b/conftest.py
index 3ea20c3..1759d04 100644
--- a/conftest.py
+++ b/conftest.py
@@ -1,10 +1,28 @@
 # Copyright (C) 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
+
 pytest_plugins = ["swh.scheduler.pytest_plugin"]
 
 os.environ["LC_ALL"] = "C.UTF-8"
+
+
+@pytest.fixture
+def mock_get_scheduler(monkeypatch, swh_scheduler):
+    """Override the get_scheduler function in swh.lister.core.lister_base, to
+    return the swh_scheduler fixture.
+    """
+    from swh.lister.core import lister_base
+
+    # Match the signature from swh.scheduler.get_scheduler
+    def get_scheduler(cls, args={}):
+        return swh_scheduler
+
+    monkeypatch.setattr(lister_base, "get_scheduler", get_scheduler)
+
+    yield monkeypatch
diff --git a/swh/lister/core/tests/conftest.py b/swh/lister/core/tests/conftest.py
index 21ce76f..647fd46 100644
--- a/swh/lister/core/tests/conftest.py
+++ b/swh/lister/core/tests/conftest.py
@@ -1,51 +1,49 @@
 # 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 logging
 import pytest
 
 from sqlalchemy import create_engine
 
 from swh.lister import get_lister, SUPPORTED_LISTERS
 from swh.lister.core.models import initialize
 
 logger = logging.getLogger(__name__)
 
 
 @pytest.fixture
 def lister_db_url(postgresql_proc, postgresql):
     db_url = "postgresql://{user}@{host}:{port}/{dbname}".format(
         host=postgresql_proc.host,
         port=postgresql_proc.port,
         user="postgres",
         dbname="tests",
     )
     logger.debug("lister db_url: %s", db_url)
     return db_url
 
 
 @pytest.fixture
-def swh_listers(request, lister_db_url, swh_scheduler):
-
+def swh_listers(mock_get_scheduler, lister_db_url, swh_scheduler):
     listers = {}
 
     # Prepare schema for all listers
     for lister_name in SUPPORTED_LISTERS:
         lister = get_lister(lister_name, db_url=lister_db_url)
-        lister.scheduler = swh_scheduler  # inject scheduler fixture
         listers[lister_name] = lister
     initialize(create_engine(lister_db_url), drop_tables=True)
 
     # Add the load-archive-files expected by some listers (gnu, cran, ...)
     swh_scheduler.create_task_type(
         {
             "type": "load-archive-files",
             "description": "Load archive files.",
             "backend_name": "swh.loader.package.tasks.LoadArchive",
             "default_interval": "1 day",
         }
     )
 
     return listers
diff --git a/swh/lister/tests/test_cli.py b/swh/lister/tests/test_cli.py
index a333804..b3be48f 100644
--- a/swh/lister/tests/test_cli.py
+++ b/swh/lister/tests/test_cli.py
@@ -1,66 +1,66 @@
 # 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 pytest
 
 
 from swh.lister.core.lister_base import ListerBase
 from swh.lister.cli import get_lister, SUPPORTED_LISTERS
 
 from .test_utils import init_db
 
 
 def test_get_lister_wrong_input():
     """Unsupported lister should raise"""
     with pytest.raises(ValueError) as e:
         get_lister("unknown", "db-url")
 
     assert "Invalid lister" in str(e.value)
 
 
-def test_get_lister():
+def test_get_lister(mock_get_scheduler):
     """Instantiating a supported lister should be ok
 
     """
     db_url = init_db().url()
     for lister_name in SUPPORTED_LISTERS:
         lst = get_lister(lister_name, db_url)
         assert isinstance(lst, ListerBase)
 
 
 def test_get_lister_override():
     """Overriding the lister configuration should populate its config
 
     """
     db_url = init_db().url()
 
     listers = {
         "gitlab": "https://other.gitlab.uni/api/v4/",
         "phabricator": "https://somewhere.org/api/diffusion.repository.search",
         "cgit": "https://some.where/cgit",
     }
 
     # check the override ends up defined in the lister
     for lister_name, url in listers.items():
         lst = get_lister(
             lister_name,
             db_url,
             **{"url": url, "priority": "high", "policy": "oneshot",},
         )
 
         assert lst.url == url
         assert lst.config["priority"] == "high"
         assert lst.config["policy"] == "oneshot"
 
     # check the default urls are used and not the override (since it's not
     # passed)
     for lister_name, url in listers.items():
         lst = get_lister(lister_name, db_url)
 
         # no override so this does not end up in lister's configuration
         assert "url" not in lst.config
         assert "priority" not in lst.config
         assert "oneshot" not in lst.config
         assert lst.url == lst.DEFAULT_URL