diff --git a/swh/lister/core/tests/conftest.py b/swh/lister/core/tests/conftest.py
index ce1039e..5d75455 100644
--- a/swh/lister/core/tests/conftest.py
+++ b/swh/lister/core/tests/conftest.py
@@ -1,26 +1,27 @@
 import pytest
 
 
 @pytest.fixture(scope='session')
 def celery_enable_logging():
     return True
 
 
 @pytest.fixture(scope='session')
 def celery_includes():
     return [
         'swh.lister.bitbucket.tasks',
         'swh.lister.debian.tasks',
         'swh.lister.github.tasks',
         'swh.lister.gitlab.tasks',
+        'swh.lister.npm.tasks',
     ]
 
 
 # override the celery_session_app fixture to monkeypatch the 'main'
 # swh.scheduler.celery_backend.config.app Celery application
 # with the test application.
 @pytest.fixture(scope='session')
 def swh_app(celery_session_app):
     import swh.scheduler.celery_backend.config
     swh.scheduler.celery_backend.config.app = celery_session_app
     yield celery_session_app
diff --git a/swh/lister/npm/tests/conftest.py b/swh/lister/npm/tests/conftest.py
new file mode 100644
index 0000000..507fef9
--- /dev/null
+++ b/swh/lister/npm/tests/conftest.py
@@ -0,0 +1 @@
+from swh.lister.core.tests.conftest import *  # noqa
diff --git a/swh/lister/npm/tests/test_tasks.py b/swh/lister/npm/tests/test_tasks.py
new file mode 100644
index 0000000..9e9deb6
--- /dev/null
+++ b/swh/lister/npm/tests/test_tasks.py
@@ -0,0 +1,55 @@
+from contextlib import contextmanager
+from unittest.mock import patch
+
+
+@contextmanager
+def mock_save(lister):
+    yield
+
+
+def test_ping(swh_app, celery_session_worker):
+    res = swh_app.send_task(
+        'swh.lister.npm.tasks.ping')
+    assert res
+    res.wait()
+    assert res.successful()
+    assert res.result == 'OK'
+
+
+@patch('swh.lister.npm.tasks.save_registry_state')
+@patch('swh.lister.npm.tasks.NpmLister')
+def test_lister(lister, save, swh_app, celery_session_worker):
+    # setup the mocked NpmLister
+    lister.return_value = lister
+    lister.run.return_value = None
+    save.side_effect = mock_save
+
+    res = swh_app.send_task('swh.lister.npm.tasks.NpmListerTask')
+    assert res
+    res.wait()
+    assert res.successful()
+
+    lister.assert_called_once_with()
+    lister.run.assert_called_once_with()
+
+
+@patch('swh.lister.npm.tasks.save_registry_state')
+@patch('swh.lister.npm.tasks.get_last_update_seq')
+@patch('swh.lister.npm.tasks.NpmIncrementalLister')
+def test_incremental(lister, seq, save, swh_app, celery_session_worker):
+    # setup the mocked NpmLister
+    lister.return_value = lister
+    lister.run.return_value = None
+    lister.request_headers.return_value = []
+    seq.return_value = 42
+    save.side_effect = mock_save
+
+    res = swh_app.send_task(
+        'swh.lister.npm.tasks.NpmIncrementalListerTask')
+    assert res
+    res.wait()
+    assert res.successful()
+
+    lister.assert_called_once_with()
+    seq.assert_called_once_with(lister)
+    lister.run.assert_called_once_with(min_bound=42)