diff --git a/swh/journal/tests/conftest.py b/swh/journal/tests/conftest.py
index 9094faa..5b35e7e 100644
--- a/swh/journal/tests/conftest.py
+++ b/swh/journal/tests/conftest.py
@@ -1,199 +1,205 @@
 # Copyright (C) 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 logging
 
 from kafka import KafkaProducer
 from subprocess import Popen
 from typing import Tuple, Dict
 
 from pathlib import Path
 from pytest_kafka import (
     make_zookeeper_process, make_kafka_server, make_kafka_consumer
 )
 
 from swh.journal.publisher import JournalPublisher
 from swh.model.hashutil import hash_to_bytes
 
 from swh.journal.serializers import kafka_to_key, key_to_kafka, kafka_to_value
 
 
 TEST_CONFIG = {
     'brokers': ['something'],  # this will be overriden in publisher setup
     'temporary_prefix': 'swh.tmp_journal.new',
     'final_prefix': 'swh.journal.objects',
     'consumer_id': 'swh.journal.publisher',
     'publisher_id': 'swh.journal.publisher',
     'object_types': ['something'],  # this will be overriden in publisher setup
     'max_messages': 1,  # will read 1 message and stops
     'storage': {'cls': 'memory', 'args': {}}
 }
 
 CONTENTS = [
     {
         'length': 3,
         'sha1': hash_to_bytes(
             '34973274ccef6ab4dfaaf86599792fa9c3fe4689'),
         'sha1_git': b'foo',
         'blake2s256': b'bar',
         'sha256': b'baz',
         'status': 'visible',
     },
 ]
 
 COMMITTER = [
     {
         'id': 1,
         'fullname': 'foo',
     },
     {
         'id': 2,
         'fullname': 'bar',
     }
 ]
 
 REVISIONS = [
     {
         'id': hash_to_bytes('7026b7c1a2af56521e951c01ed20f255fa054238'),
         'message': b'hello',
         'date': {
             'timestamp': {
                 'seconds': 1234567891,
                 'microseconds': 0,
             },
             'offset': 120,
             'negative_utc': None,
         },
         'committer': COMMITTER[0],
         'author':  COMMITTER[0],
         'committer_date': None,
     },
     {
         'id': hash_to_bytes('368a48fe15b7db2383775f97c6b247011b3f14f4'),
         'message': b'hello again',
         'date': {
             'timestamp': {
                 'seconds': 1234567892,
                 'microseconds': 0,
             },
             'offset': 120,
             'negative_utc': None,
         },
         'committer': COMMITTER[1],
         'author':  COMMITTER[1],
         'committer_date': None,
     },
 ]
 
 RELEASES = [
     {
         'id': hash_to_bytes('d81cc0710eb6cf9efd5b920a8453e1e07157b6cd'),
         'name': b'v0.0.1',
         'date': {
             'timestamp': {
                 'seconds': 1234567890,
                 'microseconds': 0,
             },
             'offset': 120,
             'negative_utc': None,
         },
         'author': COMMITTER[0],
     },
 ]
 
 ORIGINS = [
     {
         'url': 'https://somewhere.org/den/fox',
         'type': 'git',
     },
     {
         'url': 'https://overtherainbow.org/fox/den',
         'type': 'svn',
     }
 ]
 
 ORIGIN_VISITS = [
     {
         'date': '2013-05-07T04:20:39.369271+00:00',
     },
     {
         'date': '2018-11-27T17:20:39.000000+00:00',
     }
 ]
 
 
 class JournalPublisherTest(JournalPublisher):
     """A journal publisher which override the default configuration
        parsing setup.
 
     """
     def _prepare_storage(self, config):
         super()._prepare_storage(config)
         self.storage.content_add({'data': b'42', **c} for c in CONTENTS)
         self.storage.revision_add(REVISIONS)
         self.storage.release_add(RELEASES)
         origins = self.storage.origin_add(ORIGINS)
         origin_visits = []
         for i, ov in enumerate(ORIGIN_VISITS):
             origin_id = origins[i]['id']
             ov = self.storage.origin_visit_add(origin_id, ov['date'])
             origin_visits.append(ov)
             self.origins = origins
             self.origin_visits = origin_visits
 
 
-KAFKA_ROOT = os.environ.get('SWH_KAFKA_ROOT', Path(__file__).parent)
-KAFKA_SCRIPTS = KAFKA_ROOT / 'kafka/bin/'
+KAFKA_ROOT = os.environ.get('SWH_KAFKA_ROOT')
+KAFKA_ROOT = KAFKA_ROOT if KAFKA_ROOT else os.path.dirname(__file__) + '/kafka'
+if not os.path.exists(KAFKA_ROOT):
+    msg = ('Development error: %s must exist and target an '
+           'existing kafka installation' % KAFKA_ROOT)
+    raise ValueError(msg)
+
+KAFKA_SCRIPTS = Path(KAFKA_ROOT) / 'bin'
 
 KAFKA_BIN = str(KAFKA_SCRIPTS / 'kafka-server-start.sh')
 ZOOKEEPER_BIN = str(KAFKA_SCRIPTS / 'zookeeper-server-start.sh')
 
 
 # Those defines fixtures
 zookeeper_proc = make_zookeeper_process(ZOOKEEPER_BIN)
 kafka_server = make_kafka_server(KAFKA_BIN, 'zookeeper_proc')
 
 logger = logging.getLogger('kafka')
 logger.setLevel(logging.WARN)
 
 
 @pytest.fixture
 def producer_to_publisher(
         request: 'SubRequest',  # noqa F821
         kafka_server: Tuple[Popen, int]) -> KafkaProducer:  # noqa
     """Producer to send message to the publisher's consumer.
 
     """
     _, port = kafka_server
     producer = KafkaProducer(
         bootstrap_servers='localhost:{}'.format(port),
         key_serializer=key_to_kafka,
         value_serializer=key_to_kafka,
         client_id=TEST_CONFIG['consumer_id'],
     )
     return producer
 
 
 # pytest fixture (no need for the annotation though or else it breaks)
 consumer_from_publisher = make_kafka_consumer(
     'kafka_server',
     seek_to_beginning=True,
     key_deserializer=kafka_to_key,
     value_deserializer=kafka_to_value,
     auto_offset_reset='earliest',
     enable_auto_commit=True,
     client_id=TEST_CONFIG['publisher_id'],
     kafka_topics=['dummy'])  # will be overriden during test setup
 
 
 def publisher(kafka_server: Tuple[Popen, int],
               config: Dict) -> JournalPublisher:
     # consumer and producer of the publisher needs to discuss with the
     # right instance
     _, port = kafka_server
     config['brokers'] = ['localhost:{}'.format(port)]
     return JournalPublisherTest(config)