diff --git a/swh/scheduler/tests/conftest.py b/swh/scheduler/tests/conftest.py
--- a/swh/scheduler/tests/conftest.py
+++ b/swh/scheduler/tests/conftest.py
@@ -1,3 +1,9 @@
+# Copyright (C) 2016-2019  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 glob
@@ -7,16 +13,13 @@
 from swh.core.utils import numfile_sortkey as sortkey
 from swh.scheduler import get_scheduler
 from swh.scheduler.tests import SQL_DIR
+from swh.scheduler.tests.tasks import register_test_tasks
+
 
 # make sure we are not fooled by CELERY_ config environment vars
 for var in [x for x in os.environ.keys() if x.startswith('CELERY')]:
     os.environ.pop(var)
 
-import swh.scheduler.celery_backend.config  # noqa
-# this import is needed here to enforce creation of the celery current app
-# BEFORE the swh_app fixture is called, otherwise the Celery app instance from
-# celery_backend.config becomes the celery.current_app
-
 
 # test_cli tests depends on a en/C locale, so ensure it
 os.environ['LC_ALL'] = 'C.UTF-8'
@@ -61,11 +64,13 @@
 
 # override the celery_session_app fixture to monkeypatch the 'main'
 # swh.scheduler.celery_backend.config.app Celery application
-# with the test application.
+# with the test application (and also register test tasks)
 @pytest.fixture(scope='session')
 def swh_app(celery_session_app):
-    swh.scheduler.celery_backend.config.app = celery_session_app
-    yield celery_session_app
+    from swh.scheduler.celery_backend.config import app
+    register_test_tasks(celery_session_app)
+    app = celery_session_app  # noqa
+    yield app
 
 
 @pytest.fixture
diff --git a/swh/scheduler/tests/tasks.py b/swh/scheduler/tests/tasks.py
--- a/swh/scheduler/tests/tasks.py
+++ b/swh/scheduler/tests/tasks.py
@@ -1,31 +1,43 @@
-from celery import group, current_app as app
-
-
-@app.task(name='swh.scheduler.tests.tasks.ping', bind=True)
-def ping(self, **kw):
-    # check this is a SWHTask
-    assert hasattr(self, 'log')
-    assert not hasattr(self, 'run_task')
-    assert 'SWHTask' in [x.__name__ for x in self.__class__.__mro__]
-    self.log.debug(self.name)
-    if kw:
-        return 'OK (kw=%s)' % kw
-    return 'OK'
-
-
-@app.task(name='swh.scheduler.tests.tasks.multiping', bind=True)
-def multiping(self, n=10):
-    promise = group(ping.s(i=i) for i in range(n))()
-    self.log.debug('%s OK (spawned %s subtasks)' % (self.name, n))
-    promise.save()
-    return promise.id
-
-
-@app.task(name='swh.scheduler.tests.tasks.error')
-def not_implemented():
-    raise NotImplementedError('Nope')
-
-
-@app.task(name='swh.scheduler.tests.tasks.add')
-def add(x, y):
-    return x + y
+# Copyright (C) 2018-2019  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
+
+from celery import group
+
+
+def register_test_tasks(app):
+    """Register test tasks for the specific app passed as parameter.
+
+    In the test context, app is the swh_app and not the runtime one.
+
+    Args:
+        app: Celery app. Expects the tests application
+            (swh.scheduler.tests.conftest.swh_app)
+
+    """
+    @app.task(name='swh.scheduler.tests.tasks.ping', bind=True)
+    def ping(self, **kw):
+        # check this is a SWHTask
+        assert hasattr(self, 'log')
+        assert not hasattr(self, 'run_task')
+        assert 'SWHTask' in [x.__name__ for x in self.__class__.__mro__]
+        self.log.debug(self.name)
+        if kw:
+            return 'OK (kw=%s)' % kw
+        return 'OK'
+
+    @app.task(name='swh.scheduler.tests.tasks.multiping', bind=True)
+    def multiping(self, n=10):
+        promise = group(ping.s(i=i) for i in range(n))()
+        self.log.debug('%s OK (spawned %s subtasks)' % (self.name, n))
+        promise.save()
+        return promise.id
+
+    @app.task(name='swh.scheduler.tests.tasks.error')
+    def not_implemented():
+        raise NotImplementedError('Nope')
+
+    @app.task(name='swh.scheduler.tests.tasks.add')
+    def add(x, y):
+        return x + y