diff --git a/swh/loader/tar/tests/test_loader.py b/swh/loader/tar/tests/test_loader.py
index a82e130..5451370 100644
--- a/swh/loader/tar/tests/test_loader.py
+++ b/swh/loader/tar/tests/test_loader.py
@@ -1,150 +1,155 @@
 # Copyright (C) 2017-2018  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
 from unittest import TestCase
 
 from nose.plugins.attrib import attr
 from nose.tools import istest
 
 from swh.loader.tar.loader import TarLoader
 from swh.loader.core.tests import LoaderNoStorage, BaseLoaderTest
 
 
 class TarLoaderNoStorage(LoaderNoStorage, TarLoader):
     """A DirLoader with no persistence.
 
     Context:
         Load a tarball with a persistent-less tarball loader
 
     """
     def __init__(self, config={}):
         super().__init__(config=config)
         self.origin_id = 1
         self.visit = 1
 
 
 TEST_CONFIG = {
     'extraction_dir': '/tmp/tests/loader-tar/',  # where to extract the tarball
     'storage': {  # we instantiate it but we don't use it in test context
         'cls': 'remote',
         'args': {
             'url': 'http://127.0.0.1:9999',  # somewhere that does not exist
         }
     },
     'send_contents': False,
     'send_directories': False,
     'send_revisions': False,
     'send_releases': False,
     'send_snapshot': False,
     'content_packet_size': 100,
     'content_packet_block_size_bytes': 104857600,
     'content_packet_size_bytes': 1073741824,
     'directory_packet_size': 250,
     'revision_packet_size': 100,
     'release_packet_size': 100,
 }
 
 
 def parse_config_file(base_filename=None, config_filename=None,
                       additional_configs=None, global_config=True):
     return TEST_CONFIG
 
 
 # Inhibit side-effect loading configuration from disk
 TarLoader.parse_config_file = parse_config_file
 
 
-class TarLoaderTest1(TestCase):
+class TarLoaderTest(BaseLoaderTest):
+    """Prepare the archive to load
+
+    """
+    def setUp(self):
+        super().setUp('sample-folder.tgz',
+                      start_path=os.path.dirname(__file__),
+                      uncompress_archive=False)
+        self.tarpath = self.destination_path
+
+
+class TarLoaderTest1(TarLoaderTest):
     def setUp(self):
         super().setUp()
         self.loader = TarLoaderNoStorage()
 
     @attr('fs')
     @istest
     def load(self):
         """Process a new tarball should be ok
 
         """
         # given
-        start_path = os.path.dirname(__file__)
-        tarpath = os.path.join(start_path, 'resources', 'sample-folder.tgz')
-
         origin = {
             'url': 'file:///tmp/sample-folder',
             'type': 'dir'
         }
 
         visit_date = 'Tue, 3 May 2016 17:16:32 +0200'
 
         import datetime
         commit_time = int(datetime.datetime.now(
             tz=datetime.timezone.utc).timestamp()
         )
 
         swh_person = {
             'name': 'Software Heritage',
             'fullname': 'Software Heritage',
             'email': 'robot@softwareheritage.org'
         }
 
         revision_message = 'swh-loader-tar: synthetic revision message'
         revision_type = 'tar'
         revision = {
             'date': {
                 'timestamp': commit_time,
                 'offset': 0,
             },
             'committer_date': {
                 'timestamp': commit_time,
                 'offset': 0,
             },
             'author': swh_person,
             'committer': swh_person,
             'type': revision_type,
             'message': revision_message,
             'synthetic': True,
         }
 
-        branch_name = os.path.basename(tarpath)
+        branch_name = os.path.basename(self.tarpath)
 
         # when
-        self.loader.load(tar_path=tarpath, origin=origin,
+        self.loader.load(tar_path=self.tarpath, origin=origin,
                          visit_date=visit_date, revision=revision,
                          branch_name=branch_name)
 
         # then
-        self.assertEquals(len(self.loader.all_contents), 8,
-                          "8 contents: 3 files + 5 links")
-        self.assertEquals(len(self.loader.all_directories), 6,
-                          "6 directories: 4 subdirs + 1 empty + 1 main dir")
-        self.assertEquals(len(self.loader.all_revisions), 1,
-                          "synthetic revision")
-
-        actual_revision = self.loader.all_revisions[0]
+        self.assertCountContents(8, "3 files + 5 links")
+        self.assertCountDirectories(6, "4 subdirs + 1 empty + 1 main dir")
+        self.assertCountRevisions(1, "synthetic revision")
+
+        actual_revision = self.state('revision')[0]
         self.assertTrue(actual_revision['synthetic'])
         self.assertEquals(actual_revision['parents'],
                           [])
         self.assertEquals(actual_revision['type'],
                           'tar')
         self.assertEquals(actual_revision['message'],
                           b'swh-loader-tar: synthetic revision message')
         self.assertEquals(actual_revision['directory'],
                           b'\xa7A\xfcM\x96\x8c{\x8e<\x94\xff\x86\xe7\x04\x80\xc5\xc7\xe5r\xa9')  # noqa
 
         self.assertEquals(
             actual_revision['metadata']['original_artifact'][0],
             {
                 'sha1_git': 'cc848944a0d3e71d287027347e25467e61b07428',
                 'archive_type': 'tar',
                 'blake2s256': '5d70923443ad36377cd58e993aff0e3c1b9ef14f796c69569105d3a99c64f075',  # noqa
                 'name': 'sample-folder.tgz',
                 'sha1': '3ca0d0a5c6833113bd532dc5c99d9648d618f65a',
                 'length': 555,
                 'sha256': '307ebda0071ca5975f618e192c8417161e19b6c8bf581a26061b76dc8e85321d'  # noqa
             })
 
-        self.assertEquals(len(self.loader.all_releases), 0)
-        self.assertEquals(len(self.loader.all_snapshots), 1)
+        self.assertCountReleases(0)
+        self.assertCountSnapshots(1)