diff --git a/swh/indexer/tests/test_utils.py b/swh/indexer/tests/test_utils.py
index 0c519b9..826a909 100644
--- a/swh/indexer/tests/test_utils.py
+++ b/swh/indexer/tests/test_utils.py
@@ -1,409 +1,410 @@
 # Copyright (C) 2017  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 swh.objstorage.exc import ObjNotFoundError
 
 ORIGINS = [
         {
             'id': 52189575,
             'lister': None,
             'project': None,
             'type': 'git',
             'url': 'https://github.com/SoftwareHeritage/swh-storage'},
         {
             'id': 4423668,
             'lister': None,
             'project': None,
             'type': 'ftp',
             'url': 'rsync://ftp.gnu.org/gnu/3dldf'},
         {
             'id': 77775770,
             'lister': None,
             'project': None,
             'type': 'deposit',
             'url': 'https://forge.softwareheritage.org/source/jesuisgpl/'},
         {
             'id': 85072327,
             'lister': None,
             'project': None,
             'type': 'pypi',
             'url': 'https://pypi.org/project/limnoria/'},
         {
             'id': 49908349,
             'lister': None,
             'project': None,
             'type': 'svn',
             'url': 'http://0-512-md.googlecode.com/svn/'},
         {
             'id': 54974445,
             'lister': None,
             'project': None,
             'type': 'git',
             'url': 'https://github.com/librariesio/yarn-parser'},
         ]
 
 SNAPSHOTS = {
         52189575: {
             'branches': {
                 b'refs/heads/add-revision-origin-cache': {
                     'target': b'L[\xce\x1c\x88\x8eF\t\xf1"\x19\x1e\xfb\xc0'
                               b's\xe7/\xe9l\x1e',
                     'target_type': 'revision'},
                 b'HEAD': {
                     'target': b'8K\x12\x00d\x03\xcc\xe4]bS\xe3\x8f{\xd7}'
                               b'\xac\xefrm',
                     'target_type': 'revision'},
                 b'refs/tags/v0.0.103': {
                     'target': b'\xb6"Im{\xfdLb\xb0\x94N\xea\x96m\x13x\x88+'
                               b'\x0f\xdd',
                     'target_type': 'release'},
                 }},
         4423668: {
             'branches': {
                 b'3DLDF-1.1.4.tar.gz': {
                     'target': b'dJ\xfb\x1c\x91\xf4\x82B%]6\xa2\x90|\xd3\xfc'
                               b'"G\x99\x11',
                     'target_type': 'revision'},
                 b'3DLDF-2.0.2.tar.gz': {
                     'target': b'\xb6\x0e\xe7\x9e9\xac\xaa\x19\x9e='
                               b'\xd1\xc5\x00\\\xc6\xfc\xe0\xa6\xb4V',
                     'target_type': 'revision'},
                 b'3DLDF-2.0.3-examples.tar.gz': {
                     'target': b'!H\x19\xc0\xee\x82-\x12F1\xbd\x97'
                               b'\xfe\xadZ\x80\x80\xc1\x83\xff',
                     'target_type': 'revision'},
                 b'3DLDF-2.0.3.tar.gz': {
                     'target': b'\x8e\xa9\x8e/\xea}\x9feF\xf4\x9f\xfd\xee'
                               b'\xcc\x1a\xb4`\x8c\x8by',
                     'target_type': 'revision'},
                 b'3DLDF-2.0.tar.gz': {
                     'target': b'F6*\xff(?\x19a\xef\xb6\xc2\x1fv$S\xe3G'
                               b'\xd3\xd1m',
                     b'target_type': 'revision'}
                 }},
         77775770: {
             'branches': {
                 b'master': {
                     'target': b'\xe7n\xa4\x9c\x9f\xfb\xb7\xf76\x11\x08{'
                               b'\xa6\xe9\x99\xb1\x9e]q\xeb',
                     'target_type': 'revision'}
             },
             'id': b"h\xc0\xd2a\x04\xd4~'\x8d\xd6\xbe\x07\xeda\xfa\xfbV"
                   b"\x1d\r "},
         85072327: {
             'branches': {
                 b'HEAD': {
                     'target': b'releases/2018.09.09',
                     'target_type': 'alias'},
                 b'releases/2018.09.01': {
                     'target': b'<\xee1(\xe8\x8d_\xc1\xc9\xa6rT\xf1\x1d'
                               b'\xbb\xdfF\xfdw\xcf',
                     'target_type': 'revision'},
                 b'releases/2018.09.09': {
                     'target': b'\x83\xb9\xb6\xc7\x05\xb1%\xd0\xfem\xd8k'
                               b'A\x10\x9d\xc5\xfa2\xf8t',
                     'target_type': 'revision'}},
             'id': b'{\xda\x8e\x84\x7fX\xff\x92\x80^\x93V\x18\xa3\xfay'
                   b'\x12\x9e\xd6\xb3'},
         49908349: {
                 'branches': {
                     b'master': {
                         'target': b'\xe4?r\xe1,\x88\xab\xec\xe7\x9a\x87\xb8'
                                   b'\xc9\xad#.\x1bw=\x18',
                         'target_type': 'revision'}},
                 'id': b'\xa1\xa2\x8c\n\xb3\x87\xa8\xf9\xe0a\x8c\xb7'
                       b'\x05\xea\xb8\x1f\xc4H\xf4s'},
         54974445: {
                 'branches': {
                     b'HEAD': {
                         'target': b'8dbb6aeb036e7fd80664eb8bfd1507881af1ba9f',
                         'target_type': 'revision'}}}
         }
 
 
 class MockObjStorage:
     """Mock an swh-objstorage objstorage with predefined contents.
 
     """
     data = {}
 
     def __init__(self):
         self.data = {
             '01c9379dfc33803963d07c1ccc748d3fe4c96bb5': b'this is some text',
             '688a5ef812c53907562fe379d4b3851e69c7cb15': b'another text',
             '8986af901dd2043044ce8f0d8fc039153641cf17': b'yet another text',
             '02fb2c89e14f7fab46701478c83779c7beb7b069': b"""
             import unittest
             import logging
             from swh.indexer.mimetype import ContentMimetypeIndexer
             from swh.indexer.tests.test_utils import MockObjStorage
 
             class MockStorage():
                 def content_mimetype_add(self, mimetypes):
                     self.state = mimetypes
                     self.conflict_update = conflict_update
 
                 def indexer_configuration_add(self, tools):
                     return [{
                         'id': 10,
                     }]
             """,
             '103bc087db1d26afc3a0283f38663d081e9b01e6': b"""
                 #ifndef __AVL__
                 #define __AVL__
 
                 typedef struct _avl_tree avl_tree;
 
                 typedef struct _data_t {
                   int content;
                 } data_t;
             """,
             '93666f74f1cf635c8c8ac118879da6ec5623c410': b"""
             (should 'pygments (recognize 'lisp 'easily))
 
             """,
             '26a9f72a7c87cc9205725cfd879f514ff4f3d8d5': b"""
             {
                 "name": "test_metadata",
                 "version": "0.0.1",
                 "description": "Simple package.json test for indexer",
                 "repository": {
                   "type": "git",
                   "url": "https://github.com/moranegg/metadata_test"
               }
             }
             """,
             'd4c647f0fc257591cc9ba1722484229780d1c607': b"""
             {
               "version": "5.0.3",
               "name": "npm",
               "description": "a package manager for JavaScript",
               "keywords": [
                 "install",
                 "modules",
                 "package manager",
                 "package.json"
               ],
               "preferGlobal": true,
               "config": {
                 "publishtest": false
               },
               "homepage": "https://docs.npmjs.com/",
               "author": "Isaac Z. Schlueter <i@izs.me> (http://blog.izs.me)",
               "repository": {
                 "type": "git",
                 "url": "https://github.com/npm/npm"
               },
               "bugs": {
                 "url": "https://github.com/npm/npm/issues"
               },
               "dependencies": {
                 "JSONStream": "~1.3.1",
                 "abbrev": "~1.1.0",
                 "ansi-regex": "~2.1.1",
                 "ansicolors": "~0.3.2",
                 "ansistyles": "~0.1.3"
               },
               "devDependencies": {
                 "tacks": "~1.2.6",
                 "tap": "~10.3.2"
               },
               "license": "Artistic-2.0"
             }
 
             """,
             'a7ab314d8a11d2c93e3dcf528ca294e7b431c449': b"""
             """,
             'da39a3ee5e6b4b0d3255bfef95601890afd80709': b'',
         }
 
     def __iter__(self):
         yield from self.data.keys()
 
     def __contains__(self, sha1):
         return self.data.get(sha1) is not None
 
     def get(self, sha1):
         raw_content = self.data.get(sha1)
         if raw_content is None:
             raise ObjNotFoundError(sha1)
         return raw_content
 
 
 class MockIndexerStorage():
     """Mock an swh-indexer storage.
 
     """
     added_data = []
 
     def indexer_configuration_add(self, tools):
         tool = tools[0]
         if tool['tool_name'] == 'swh-metadata-translator':
             return [{
                 'id': 30,
                 'tool_name': 'swh-metadata-translator',
                 'tool_version': '0.0.1',
                 'tool_configuration': {
                     'type': 'local',
                     'context': 'NpmMapping'
                 },
             }]
         elif tool['tool_name'] == 'swh-metadata-detector':
             return [{
                 'id': 7,
                 'tool_name': 'swh-metadata-detector',
                 'tool_version': '0.0.1',
                 'tool_configuration': {
                     'type': 'local',
                     'context': 'NpmMapping'
                 },
             }]
         elif tool['tool_name'] == 'origin-metadata':
             return [{
                 'id': 8,
                 'tool_name': 'origin-metadata',
                 'tool_version': '0.0.1',
                 'tool_configuration': {},
             }]
         else:
             assert False, 'Unknown tool {tool_name}'.format(**tool)
 
     def content_metadata_missing(self, sha1s):
         yield from []
 
     def content_metadata_add(self, metadata, conflict_update=None):
         self.added_data.append(
                 ('content_metadata', conflict_update, metadata))
 
     def revision_metadata_add(self, metadata, conflict_update=None):
         self.added_data.append(
                 ('revision_metadata', conflict_update, metadata))
 
     def origin_intrinsic_metadata_add(self, metadata, conflict_update=None):
         self.added_data.append(
                 ('origin_intrinsic_metadata', conflict_update, metadata))
 
     def content_metadata_get(self, sha1s):
         return [{
             'tool': {
                 'configuration': {
                     'type': 'local',
                     'context': 'NpmMapping'
                     },
                 'version': '0.0.1',
                 'id': 6,
                 'name': 'swh-metadata-translator'
             },
             'id': b'cde',
             'translated_metadata': {
                 'issueTracker': {
                     'url': 'https://github.com/librariesio/yarn-parser/issues'
                 },
                 'version': '1.0.0',
                 'name': 'yarn-parser',
                 'author': 'Andrew Nesbitt',
                 'url': 'https://github.com/librariesio/yarn-parser#readme',
                 'processorRequirements': {'node': '7.5'},
                 'other': {
                     'scripts': {
                                     'start': 'node index.js'
                     },
                     'main': 'index.js'
                 },
                 'license': 'AGPL-3.0',
                 'keywords': ['yarn', 'parse', 'lock', 'dependencies'],
                 'codeRepository': {
                     'type': 'git',
                     'url': 'git+https://github.com/librariesio/yarn-parser.git'
                 },
                 'description': 'Tiny web service for parsing yarn.lock files',
                 'softwareRequirements': {
                     'yarn': '^0.21.0',
                     'express': '^4.14.0',
                     'body-parser': '^1.15.2'}
                 }
         }]
 
 
 class MockStorage():
     """Mock a real swh-storage storage to simplify reading indexers'
     outputs.
 
     """
     def origin_get(self, id_):
         for origin in ORIGINS:
             for (k, v) in id_.items():
                 if origin[k] != v:
                     break
             else:
-                # This block is run iff we didn't break, ie. if all supplied
-                # parts of the id are set to the expected value.
+                # This block is run if and only if we didn't break,
+                # ie. if all supplied parts of the id are set to the
+                # expected value.
                 return origin
         assert False, id_
 
     def snapshot_get_latest(self, origin_id):
         if origin_id in SNAPSHOTS:
             return SNAPSHOTS[origin_id]
         else:
             assert False, origin_id
 
     def revision_get(self, revisions):
         return [{
             'id': b'8dbb6aeb036e7fd80664eb8bfd1507881af1ba9f',
             'committer': {
                 'id': 26,
                 'name': b'Andrew Nesbitt',
                 'fullname': b'Andrew Nesbitt <andrewnez@gmail.com>',
                 'email': b'andrewnez@gmail.com'
             },
             'synthetic': False,
             'date': {
                 'negative_utc': False,
                 'timestamp': {
                     'seconds': 1487596456,
                     'microseconds': 0
                 },
                 'offset': 0
             },
             'directory': b'10'
         }]
 
     def directory_ls(self, directory, recursive=False, cur=None):
         # with directory: b'\x9d',
         return [{
                 'sha1_git': b'abc',
                 'name': b'index.js',
                 'target': b'abc',
                 'length': 897,
                 'status': 'visible',
                 'type': 'file',
                 'perms': 33188,
                 'dir_id': b'10',
                 'sha1': b'bcd'
                 },
                 {
                 'sha1_git': b'aab',
                 'name': b'package.json',
                 'target': b'aab',
                 'length': 712,
                 'status': 'visible',
                 'type': 'file',
                 'perms': 33188,
                 'dir_id': b'10',
                 'sha1': b'cde'
                 },
                 {
                 'dir_id': b'10',
                 'target': b'11',
                 'type': 'dir',
                 'length': None,
                 'name': b'.github',
                 'sha1': None,
                 'perms': 16384,
                 'sha1_git': None,
                 'status': None,
                 'sha256': None
                 }]