diff --git a/swh/core/tests/test_config.py b/swh/core/tests/test_config.py
index c2fb5bd..c8bf3bc 100644
--- a/swh/core/tests/test_config.py
+++ b/swh/core/tests/test_config.py
@@ -1,84 +1,88 @@
 # Copyright (C) 2015  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 tempfile
 import unittest
 import os
 import shutil
 
 from nose.tools import istest
 
 from swh.core import config
 
 
 class ConfReaderTest(unittest.TestCase):
 
     @classmethod
-    def setUp(self):
+    def setUp(cls):
         # create a temporary folder
-        self.tmpdir = tempfile.mkdtemp(prefix='test-swh-core.')
-        self.conffile = os.path.join(self.tmpdir, 'config.ini')
-        with open(self.conffile, 'w') as conf:
+        cls.tmpdir = tempfile.mkdtemp(prefix='test-swh-core.')
+        cls.conffile = os.path.join(cls.tmpdir, 'config.ini')
+        with open(cls.conffile, 'w') as conf:
             conf.write("""[main]
 a = 1
 b = this is a string
 c = true
 """)
 
     @classmethod
-    def tearDown(self):
-        shutil.rmtree(self.tmpdir)
+    def tearDown(cls):
+        shutil.rmtree(cls.tmpdir)
 
     @istest
     def read(self):
         # given
-        default_conf = {'a': ('int', 2),
-                        'b': ('string', 'default-string'),
-                        'c': ('bool', True),
-                        'd': ('int', 10),
-                        'e': ('int', None),
-                        'f': ('bool', None),
-                        'g': ('string', None),}
+        default_conf = {
+            'a': ('int', 2),
+            'b': ('string', 'default-string'),
+            'c': ('bool', True),
+            'd': ('int', 10),
+            'e': ('int', None),
+            'f': ('bool', None),
+            'g': ('string', None),
+        }
 
         # when
         res = config.read(self.conffile, default_conf)
 
         # then
-        self.assertEquals(res, {'a': 1,
-                                'b': 'this is a string',
-                                'c': True,
-                                'd': 10,
-                                'e': None,
-                                'f': None,
-                                'g': None})
+        self.assertEquals(res, {
+            'a': 1,
+            'b': 'this is a string',
+            'c': True,
+            'd': 10,
+            'e': None,
+            'f': None,
+            'g': None,
+        })
 
     @istest
     def prepare_folder(self):
         # given
         conf = {'path1': os.path.join(self.tmpdir, 'path1'),
                 'path2': os.path.join(self.tmpdir, 'path2', 'depth1')}
 
         # the folders does not exists
         self.assertFalse(os.path.exists(conf['path1']),
                          "path1 should not exist.")
         self.assertFalse(os.path.exists(conf['path2']),
                          "path2 should not exist.")
 
         # when
         config.prepare_folders(conf, 'path1')
 
         # path1 exists but not path2
         self.assertTrue(os.path.exists(conf['path1']),
                         "path1 should now exist!")
         self.assertFalse(os.path.exists(conf['path2']),
                          "path2 should not exist.")
 
         # path1 already exists, skips it but creates path2
         config.prepare_folders(conf, 'path1', 'path2')
 
         self.assertTrue(os.path.exists(conf['path1']),
                         "path1 should still exist!")
         self.assertTrue(os.path.exists(conf['path2']),
                         "path2 should now exist.")