diff --git a/swh/loader/package/tests/test_npm.py b/swh/loader/package/tests/test_npm.py
index 27994df..d06004c 100644
--- a/swh/loader/package/tests/test_npm.py
+++ b/swh/loader/package/tests/test_npm.py
@@ -1,474 +1,445 @@
 # 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 json
 import os
 import re
-import unittest
 
 from swh.model.hashutil import hash_to_bytes
 
 from swh.loader.package.npm import (
     parse_npm_package_author, extract_npm_package_author
 )
 from swh.loader.package.tests.common import (
     DATADIR, get_response_cb, check_snapshot
 )
 from swh.loader.package.npm import NpmLoader
 
 
-def package_metadata_file(package, visit=''):
-    json_filename = '%s_metadata' % package
-    if visit:
-        json_filename += '_visit%s' % visit
-    json_filename += '.json'
-    return json_filename
+def _parse_author_string_test(author_str, expected_result):
+    assert parse_npm_package_author(author_str) == expected_result
+    assert parse_npm_package_author(' %s' % author_str) == expected_result
+    assert parse_npm_package_author('%s ' % author_str) == expected_result
 
 
-class TestNpmClient(unittest.TestCase):
-
-    def _parse_author_string_test(self, author_str, expected_result):
-        self.assertEqual(
-            parse_npm_package_author(author_str),
-            expected_result
-        )
-        self.assertEqual(
-            parse_npm_package_author(' %s' % author_str),
-            expected_result
-        )
-        self.assertEqual(
-            parse_npm_package_author('%s ' % author_str),
-            expected_result
-        )
-
-    def test_parse_npm_package_author(self):
-
-        self._parse_author_string_test(
-            'John Doe',
-            {
-                'name': 'John Doe'
-            }
-        )
-
-        self._parse_author_string_test(
-            '<john.doe@foo.bar>',
-            {
-                'email': 'john.doe@foo.bar'
-            }
-        )
-
-        self._parse_author_string_test(
-            '(https://john.doe)',
-            {
-                'url': 'https://john.doe'
-            }
-        )
-
-        self._parse_author_string_test(
-            'John Doe <john.doe@foo.bar>',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar'
-            }
-        )
-
-        self._parse_author_string_test(
-            'John Doe<john.doe@foo.bar>',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar'
-            }
-        )
+def test_parse_npm_package_author():
+    _parse_author_string_test(
+        'John Doe',
+        {
+            'name': 'John Doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe (https://john.doe)',
-            {
-                'name': 'John Doe',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        '<john.doe@foo.bar>',
+        {
+            'email': 'john.doe@foo.bar'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe(https://john.doe)',
-            {
-                'name': 'John Doe',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        '(https://john.doe)',
+        {
+            'url': 'https://john.doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            '<john.doe@foo.bar> (https://john.doe)',
-            {
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe <john.doe@foo.bar>',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar'
+        }
+    )
 
-        self._parse_author_string_test(
-            '(https://john.doe) <john.doe@foo.bar>',
-            {
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe<john.doe@foo.bar>',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe <john.doe@foo.bar> (https://john.doe)',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe (https://john.doe)',
+        {
+            'name': 'John Doe',
+            'url': 'https://john.doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe (https://john.doe) <john.doe@foo.bar>',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe(https://john.doe)',
+        {
+            'name': 'John Doe',
+            'url': 'https://john.doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe<john.doe@foo.bar> (https://john.doe)',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
+    _parse_author_string_test(
+        '<john.doe@foo.bar> (https://john.doe)',
+        {
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe<john.doe@foo.bar>(https://john.doe)',
-            {
-                'name': 'John Doe',
-                'email': 'john.doe@foo.bar',
-                'url': 'https://john.doe'
-            }
-        )
-
-        self._parse_author_string_test('', {})
-        self._parse_author_string_test('<>', {})
-        self._parse_author_string_test(' <>', {})
-        self._parse_author_string_test('<>()', {})
-        self._parse_author_string_test('<> ()', {})
-        self._parse_author_string_test('()', {})
-        self._parse_author_string_test(' ()', {})
-
-        self._parse_author_string_test(
-            'John Doe <> ()',
-            {
-                'name': 'John Doe'
-            }
-        )
+    _parse_author_string_test(
+        '(https://john.doe) <john.doe@foo.bar>',
+        {
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe <>',
-            {
-                'name': 'John Doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe <john.doe@foo.bar> (https://john.doe)',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
+
+    _parse_author_string_test(
+        'John Doe (https://john.doe) <john.doe@foo.bar>',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
+
+    _parse_author_string_test(
+        'John Doe<john.doe@foo.bar> (https://john.doe)',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
+
+    _parse_author_string_test(
+        'John Doe<john.doe@foo.bar>(https://john.doe)',
+        {
+            'name': 'John Doe',
+            'email': 'john.doe@foo.bar',
+            'url': 'https://john.doe'
+        }
+    )
+
+    _parse_author_string_test('', {})
+    _parse_author_string_test('<>', {})
+    _parse_author_string_test(' <>', {})
+    _parse_author_string_test('<>()', {})
+    _parse_author_string_test('<> ()', {})
+    _parse_author_string_test('()', {})
+    _parse_author_string_test(' ()', {})
+
+    _parse_author_string_test(
+        'John Doe <> ()',
+        {
+            'name': 'John Doe'
+        }
+    )
 
-        self._parse_author_string_test(
-            'John Doe ()',
-            {
-                'name': 'John Doe'
-            }
-        )
+    _parse_author_string_test(
+        'John Doe <>',
+        {
+            'name': 'John Doe'
+        }
+    )
 
-    def test_extract_npm_package_author(self):
-        package_metadata_filepath = os.path.join(
-            DATADIR, 'replicate.npmjs.com', 'org_metadata_visit2.json')
+    _parse_author_string_test(
+        'John Doe ()',
+        {
+            'name': 'John Doe'
+        }
+    )
 
-        with open(package_metadata_filepath) as json_file:
-            package_metadata = json.load(json_file)
 
-        self.assertEqual(
-            extract_npm_package_author(package_metadata['versions']['0.0.2']),
-            {
-                'fullname': b'mooz <stillpedant@gmail.com>',
-                'name': b'mooz',
-                'email': b'stillpedant@gmail.com'
-            }
-        )
+def test_extract_npm_package_author():
+    package_metadata_filepath = os.path.join(
+        DATADIR, 'replicate.npmjs.com', 'org_metadata_visit2.json')
 
-        self.assertEqual(
-            extract_npm_package_author(package_metadata['versions']['0.0.3']),
-            {
-                'fullname': b'Masafumi Oyamada <stillpedant@gmail.com>',
-                'name': b'Masafumi Oyamada',
-                'email': b'stillpedant@gmail.com'
-            }
-        )
+    with open(package_metadata_filepath) as json_file:
+        package_metadata = json.load(json_file)
 
-        package_json = json.loads('''
+    extract_npm_package_author(package_metadata['versions']['0.0.2']) == \
         {
-            "name": "highlightjs-line-numbers.js",
-            "version": "2.7.0",
-            "description": "Highlight.js line numbers plugin.",
-            "main": "src/highlightjs-line-numbers.js",
-            "dependencies": {},
-            "devDependencies": {
-                "gulp": "^4.0.0",
-                "gulp-rename": "^1.4.0",
-                "gulp-replace": "^0.6.1",
-                "gulp-uglify": "^1.2.0"
-            },
-            "repository": {
-                "type": "git",
-                "url": "https://github.com/wcoder/highlightjs-line-numbers.js.git"
-            },
-            "author": "Yauheni Pakala <evgeniy.pakalo@gmail.com>",
-            "license": "MIT",
-            "bugs": {
-                "url": "https://github.com/wcoder/highlightjs-line-numbers.js/issues"
-            },
-            "homepage": "http://wcoder.github.io/highlightjs-line-numbers.js/"
-        }''') # noqa
-
-        self.assertEqual(
-            extract_npm_package_author(package_json),
-            {
-                'fullname': b'Yauheni Pakala <evgeniy.pakalo@gmail.com>',
-                'name': b'Yauheni Pakala',
-                'email': b'evgeniy.pakalo@gmail.com'
-            }
-        )
+            'fullname': b'mooz <stillpedant@gmail.com>',
+            'name': b'mooz',
+            'email': b'stillpedant@gmail.com'
+        }
 
-        package_json = json.loads('''
+    assert (
+        extract_npm_package_author(package_metadata['versions']['0.0.3']) ==
         {
-            "name": "3-way-diff",
-            "version": "0.0.1",
-            "description": "3-way diffing of JavaScript objects",
-            "main": "index.js",
-            "authors": [
-                {
-                    "name": "Shawn Walsh",
-                    "url": "https://github.com/shawnpwalsh"
-                },
-                {
-                    "name": "Markham F Rollins IV",
-                    "url": "https://github.com/mrollinsiv"
-                }
-            ],
-            "keywords": [
-                "3-way diff",
-                "3 way diff",
-                "three-way diff",
-                "three way diff"
-            ],
-            "devDependencies": {
-                "babel-core": "^6.20.0",
-                "babel-preset-es2015": "^6.18.0",
-                "mocha": "^3.0.2"
-            },
-            "dependencies": {
-                "lodash": "^4.15.0"
-            }
-        }''')
-
-        self.assertEqual(
-            extract_npm_package_author(package_json),
-            {
-                'fullname': b'Shawn Walsh',
-                'name': b'Shawn Walsh',
-                'email': None
-            }
-        )
-
-        package_json = json.loads('''
+            'fullname': b'Masafumi Oyamada <stillpedant@gmail.com>',
+            'name': b'Masafumi Oyamada',
+            'email': b'stillpedant@gmail.com'
+        }
+    )
+
+    package_json = json.loads('''
+    {
+        "name": "highlightjs-line-numbers.js",
+        "version": "2.7.0",
+        "description": "Highlight.js line numbers plugin.",
+        "main": "src/highlightjs-line-numbers.js",
+        "dependencies": {},
+        "devDependencies": {
+            "gulp": "^4.0.0",
+            "gulp-rename": "^1.4.0",
+            "gulp-replace": "^0.6.1",
+            "gulp-uglify": "^1.2.0"
+        },
+        "repository": {
+            "type": "git",
+            "url": "https://github.com/wcoder/highlightjs-line-numbers.js.git"
+        },
+        "author": "Yauheni Pakala <evgeniy.pakalo@gmail.com>",
+        "license": "MIT",
+        "bugs": {
+            "url": "https://github.com/wcoder/highlightjs-line-numbers.js/issues"
+        },
+        "homepage": "http://wcoder.github.io/highlightjs-line-numbers.js/"
+    }''') # noqa
+
+    assert extract_npm_package_author(package_json) == \
         {
-            "name": "yfe-ynpm",
-            "version": "1.0.0",
-            "homepage": "http://gitlab.ywwl.com/yfe/yfe-ynpm",
-            "repository": {
-                "type": "git",
-                "url": "git@gitlab.ywwl.com:yfe/yfe-ynpm.git"
-            },
-            "author": [
-                "fengmk2 <fengmk2@gmail.com> (https://fengmk2.com)",
-                "xufuzi <xufuzi@ywwl.com> (https://7993.org)"
-            ],
-            "license": "MIT"
-        }''')
-
-        self.assertEqual(
-            extract_npm_package_author(package_json),
+            'fullname': b'Yauheni Pakala <evgeniy.pakalo@gmail.com>',
+            'name': b'Yauheni Pakala',
+            'email': b'evgeniy.pakalo@gmail.com'
+        }
+
+    package_json = json.loads('''
+    {
+        "name": "3-way-diff",
+        "version": "0.0.1",
+        "description": "3-way diffing of JavaScript objects",
+        "main": "index.js",
+        "authors": [
             {
-                'fullname': b'fengmk2 <fengmk2@gmail.com>',
-                'name': b'fengmk2',
-                'email': b'fengmk2@gmail.com'
-            }
-        )
-
-        package_json = json.loads('''
-        {
-            "name": "umi-plugin-whale",
-            "version": "0.0.8",
-            "description": "Internal contract component",
-            "authors": {
-                "name": "xiaohuoni",
-                "email": "448627663@qq.com"
+                "name": "Shawn Walsh",
+                "url": "https://github.com/shawnpwalsh"
             },
-            "repository": "alitajs/whale",
-            "devDependencies": {
-                "np": "^3.0.4",
-                "umi-tools": "*"
-            },
-            "license": "MIT"
-        }''')
-
-        self.assertEqual(
-            extract_npm_package_author(package_json),
             {
-                'fullname': b'xiaohuoni <448627663@qq.com>',
-                'name': b'xiaohuoni',
-                'email': b'448627663@qq.com'
+                "name": "Markham F Rollins IV",
+                "url": "https://github.com/mrollinsiv"
             }
-        )
+        ],
+        "keywords": [
+            "3-way diff",
+            "3 way diff",
+            "three-way diff",
+            "three way diff"
+        ],
+        "devDependencies": {
+            "babel-core": "^6.20.0",
+            "babel-preset-es2015": "^6.18.0",
+            "mocha": "^3.0.2"
+        },
+        "dependencies": {
+            "lodash": "^4.15.0"
+        }
+    }''')
+
+    assert extract_npm_package_author(package_json) == \
+        {
+            'fullname': b'Shawn Walsh',
+            'name': b'Shawn Walsh',
+            'email': None
+        }
+
+    package_json = json.loads('''
+    {
+        "name": "yfe-ynpm",
+        "version": "1.0.0",
+        "homepage": "http://gitlab.ywwl.com/yfe/yfe-ynpm",
+        "repository": {
+            "type": "git",
+            "url": "git@gitlab.ywwl.com:yfe/yfe-ynpm.git"
+        },
+        "author": [
+            "fengmk2 <fengmk2@gmail.com> (https://fengmk2.com)",
+            "xufuzi <xufuzi@ywwl.com> (https://7993.org)"
+        ],
+        "license": "MIT"
+    }''')
+
+    assert extract_npm_package_author(package_json) == \
+        {
+            'fullname': b'fengmk2 <fengmk2@gmail.com>',
+            'name': b'fengmk2',
+            'email': b'fengmk2@gmail.com'
+        }
+
+    package_json = json.loads('''
+    {
+        "name": "umi-plugin-whale",
+        "version": "0.0.8",
+        "description": "Internal contract component",
+        "authors": {
+            "name": "xiaohuoni",
+            "email": "448627663@qq.com"
+        },
+        "repository": "alitajs/whale",
+        "devDependencies": {
+            "np": "^3.0.4",
+            "umi-tools": "*"
+        },
+        "license": "MIT"
+    }''')
+
+    assert extract_npm_package_author(package_json) == \
+        {
+            'fullname': b'xiaohuoni <448627663@qq.com>',
+            'name': b'xiaohuoni',
+            'email': b'448627663@qq.com'
+        }
 
 
 def normalize_hashes(hashes):
     if isinstance(hashes, str):
         return hash_to_bytes(hashes)
     if isinstance(hashes, list):
         return [hash_to_bytes(x) for x in hashes]
     return {hash_to_bytes(k): hash_to_bytes(v) for k, v in hashes.items()}
 
 
 _expected_new_contents_first_visit = normalize_hashes([
     '4ce3058e16ab3d7e077f65aabf855c34895bf17c',
     '858c3ceee84c8311adc808f8cdb30d233ddc9d18',
     '0fa33b4f5a4e0496da6843a38ff1af8b61541996',
     '85a410f8ef8eb8920f2c384a9555566ad4a2e21b',
     '9163ac8025923d5a45aaac482262893955c9b37b',
     '692cf623b8dd2c5df2c2998fd95ae4ec99882fb4',
     '18c03aac6d3e910efb20039c15d70ab5e0297101',
     '41265c42446aac17ca769e67d1704f99e5a1394d',
     '783ff33f5882813dca9239452c4a7cadd4dba778',
     'b029cfb85107aee4590c2434a3329bfcf36f8fa1',
     '112d1900b4c2e3e9351050d1b542c9744f9793f3',
     '5439bbc4bd9a996f1a38244e6892b71850bc98fd',
     'd83097a2f994b503185adf4e719d154123150159',
     'd0939b4898e83090ee55fd9d8a60e312cfadfbaf',
     'b3523a26f7147e4af40d9d462adaae6d49eda13e',
     'cd065fb435d6fb204a8871bcd623d0d0e673088c',
     '2854a40855ad839a54f4b08f5cff0cf52fca4399',
     'b8a53bbaac34ebb8c6169d11a4b9f13b05c583fe',
     '0f73d56e1cf480bded8a1ecf20ec6fc53c574713',
     '0d9882b2dfafdce31f4e77fe307d41a44a74cefe',
     '585fc5caab9ead178a327d3660d35851db713df1',
     'e8cd41a48d79101977e3036a87aeb1aac730686f',
     '5414efaef33cceb9f3c9eb5c4cc1682cd62d14f7',
     '9c3cc2763bf9e9e37067d3607302c4776502df98',
     '3649a68410e354c83cd4a38b66bd314de4c8f5c9',
     'e96ed0c091de1ebdf587104eaf63400d1974a1fe',
     '078ca03d2f99e4e6eab16f7b75fbb7afb699c86c',
     '38de737da99514de6559ff163c988198bc91367a',
 ])
 
 _expected_new_directories_first_visit = normalize_hashes([
     '3370d20d6f96dc1c9e50f083e2134881db110f4f',
     '42753c0c2ab00c4501b552ac4671c68f3cf5aece',
     'd7895533ef5edbcffdea3f057d9fef3a1ef845ce',
     '80579be563e2ef3e385226fe7a3f079b377f142c',
     '3b0ddc6a9e58b4b53c222da4e27b280b6cda591c',
     'bcad03ce58ac136f26f000990fc9064e559fe1c0',
     '5fc7e82a1bc72e074665c6078c6d3fad2f13d7ca',
     'e3cd26beba9b1e02f6762ef54bd9ac80cc5f25fd',
     '584b5b4b6cf7f038095e820b99386a9c232de931',
     '184c8d6d0d242f2b1792ef9d3bf396a5434b7f7a',
     'bb5f4ee143c970367eb409f2e4c1104898048b9d',
     '1b95491047add1103db0dfdfa84a9735dcb11e88',
     'a00c6de13471a2d66e64aca140ddb21ef5521e62',
     '5ce6c1cd5cda2d546db513aaad8c72a44c7771e2',
     'c337091e349b6ac10d38a49cdf8c2401ef9bb0f2',
     '202fafcd7c0f8230e89d5496ad7f44ab12b807bf',
     '775cc516543be86c15c1dc172f49c0d4e6e78235',
     'ff3d1ead85a14f891e8b3fa3a89de39db1b8de2e',
 ])
 
 _expected_new_revisions_first_visit = normalize_hashes({
     'd8a1c7474d2956ac598a19f0f27d52f7015f117e':
     '42753c0c2ab00c4501b552ac4671c68f3cf5aece',
     '5f9eb78af37ffd12949f235e86fac04898f9f72a':
     '3370d20d6f96dc1c9e50f083e2134881db110f4f',
     'ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a':
     'd7895533ef5edbcffdea3f057d9fef3a1ef845ce'}
 )
 
 _expected_new_snapshot_first_visit_id = normalize_hashes(
     'd0587e1195aed5a8800411a008f2f2d627f18e2d')
 
 _expected_branches_first_visit = {
     'HEAD': {
         'target': 'releases/0.0.4',
         'target_type': 'alias'
     },
     'releases/0.0.2': {
         'target': 'd8a1c7474d2956ac598a19f0f27d52f7015f117e',
         'target_type': 'revision'
     },
     'releases/0.0.3': {
         'target': '5f9eb78af37ffd12949f235e86fac04898f9f72a',
         'target_type': 'revision'
     },
     'releases/0.0.4': {
         'target': 'ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a',
         'target_type': 'revision'
     }
 }
 
 
 def package_url(package):
     return 'https://www.npmjs.com/package/%s' % package
 
 
 def package_metadata_url(package):
     return 'https://replicate.npmjs.com/%s/' % package
 
 
 def test_npm_loader_2_first_visit(swh_config, requests_mock):
 
     package = 'org'
     requests_mock.get(re.compile('https://'),
                       body=get_response_cb)
     loader = NpmLoader(package,
                        package_url(package),
                        package_metadata_url(package))
 
     actual_load_status = loader.load()
     assert actual_load_status == {'status': 'eventful'}
 
     stats = loader.storage.stat_counters()
 
     assert {
         'content': len(_expected_new_contents_first_visit),
         'directory': len(_expected_new_directories_first_visit),
         'origin': 1,
         'origin_visit': 1,
         'person': 2,
         'release': 0,
         'revision': len(_expected_new_revisions_first_visit),
         'skipped_content': 0,
         'snapshot': 1,
     } == stats
 
     assert len(list(loader.storage.content_get(
         _expected_new_contents_first_visit))) == len(
             _expected_new_contents_first_visit)
 
     assert list(loader.storage.directory_missing(
         _expected_new_directories_first_visit)) == []
 
     assert list(loader.storage.revision_missing(
         _expected_new_revisions_first_visit)) == []
 
     check_snapshot(
         _expected_new_snapshot_first_visit_id,
         _expected_branches_first_visit,
         storage=loader.storage)