diff --git a/swh/loader/package/archive/tests/test_archive.py b/swh/loader/package/archive/tests/test_archive.py
index 410961d..b917f8b 100644
--- a/swh/loader/package/archive/tests/test_archive.py
+++ b/swh/loader/package/archive/tests/test_archive.py
@@ -1,344 +1,344 @@
 # Copyright (C) 2019-2020 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.model.hashutil import hash_to_bytes
 
 from swh.loader.package.archive.loader import ArchiveLoader
 from swh.loader.package.tests.common import check_metadata_paths
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 
 URL = "https://ftp.gnu.org/gnu/8sync/"
 GNU_ARTIFACTS = [
     {
         "time": 944729610,
         "url": "https://ftp.gnu.org/gnu/8sync/8sync-0.1.0.tar.gz",
         "length": 221837,
         "filename": "8sync-0.1.0.tar.gz",
         "version": "0.1.0",
     }
 ]
 
 _expected_new_contents_first_visit = [
     "e9258d81faf5881a2f96a77ba609396f82cb97ad",
     "1170cf105b04b7e2822a0e09d2acf71da7b9a130",
     "fbd27c3f41f2668624ffc80b7ba5db9b92ff27ac",
     "0057bec9b5422aff9256af240b177ac0e3ac2608",
     "2b8d0d0b43a1078fc708930c8ddc2956a86c566e",
     "27de3b3bc6545d2a797aeeb4657c0e215a0c2e55",
     "2e6db43f5cd764e677f416ff0d0c78c7a82ef19b",
     "ae9be03bd2a06ed8f4f118d3fe76330bb1d77f62",
     "edeb33282b2bffa0e608e9d2fd960fd08093c0ea",
     "d64e64d4c73679323f8d4cde2643331ba6c20af9",
     "7a756602914be889c0a2d3952c710144b3e64cb0",
     "84fb589b554fcb7f32b806951dcf19518d67b08f",
     "8624bcdae55baeef00cd11d5dfcfa60f68710a02",
     "e08441aeab02704cfbd435d6445f7c072f8f524e",
     "f67935bc3a83a67259cda4b2d43373bd56703844",
     "809788434b433eb2e3cfabd5d591c9a659d5e3d8",
     "7d7c6c8c5ebaeff879f61f37083a3854184f6c41",
     "b99fec102eb24bffd53ab61fc30d59e810f116a2",
     "7d149b28eaa228b3871c91f0d5a95a2fa7cb0c68",
     "f0c97052e567948adf03e641301e9983c478ccff",
     "7fb724242e2b62b85ca64190c31dcae5303e19b3",
     "4f9709e64a9134fe8aefb36fd827b84d8b617ab5",
     "7350628ccf194c2c3afba4ac588c33e3f3ac778d",
     "0bb892d9391aa706dc2c3b1906567df43cbe06a2",
     "49d4c0ce1a16601f1e265d446b6c5ea6b512f27c",
     "6b5cc594ac466351450f7f64a0b79fdaf4435ad3",
     "3046e5d1f70297e2a507b98224b6222c9688d610",
     "1572607d456d7f633bc6065a2b3048496d679a31",
 ]
 
 _expected_new_directories_first_visit = [
     "daabc65ec75d487b1335ffc101c0ac11c803f8fc",
     "263be23b4a8101d3ad0d9831319a3e0f2b065f36",
     "7f6e63ba6eb3e2236f65892cd822041f1a01dd5c",
     "4db0a3ecbc976083e2dac01a62f93729698429a3",
     "dfef1c80e1098dd5deda664bb44a9ab1f738af13",
     "eca971d346ea54d95a6e19d5051f900237fafdaa",
     "3aebc29ed1fccc4a6f2f2010fb8e57882406b528",
 ]
 
 _expected_new_revisions_first_visit = {
     "44183488c0774ce3c957fa19ba695cf18a4a42b3": (
         "3aebc29ed1fccc4a6f2f2010fb8e57882406b528"
     )
 }
 
 _expected_branches_first_visit = {
-    "HEAD": {"target_type": "alias", "target": "releases/0.1.0",},
-    "releases/0.1.0": {
+    b"HEAD": {"target_type": "alias", "target": b"releases/0.1.0",},
+    b"releases/0.1.0": {
         "target_type": "revision",
-        "target": "44183488c0774ce3c957fa19ba695cf18a4a42b3",
+        "target": hash_to_bytes("44183488c0774ce3c957fa19ba695cf18a4a42b3"),
     },
 }
 
 # hash is different then before as we changed the snapshot
 # gnu used to use `release/` (singular) instead of plural
 _expected_new_snapshot_first_visit_id = (
     "c419397fd912039825ebdbea378bc6283f006bf5"  # noqa
 )
 
 
 def visit_with_no_artifact_found(swh_config, requests_mock_datadir):
     url = URL
     unknown_artifact_url = "https://ftp.g.o/unknown/8sync-0.1.0.tar.gz"
     loader = ArchiveLoader(
         url,
         artifacts=[
             {
                 "time": 944729610,
                 "url": unknown_artifact_url,  # unknown artifact
                 "length": 221837,
                 "filename": "8sync-0.1.0.tar.gz",
                 "version": "0.1.0",
             }
         ],
     )
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
     assert actual_load_status["snapshot_id"] is not None
     stats = get_stats(loader.storage)
 
     assert {
         "content": 0,
         "directory": 0,
         "origin": 1,
         "origin_visit": 1,
         "person": 0,
         "release": 0,
         "revision": 0,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="tar")
 
 
 def test_check_revision_metadata_structure(swh_config, requests_mock_datadir):
     loader = ArchiveLoader(url=URL, artifacts=GNU_ARTIFACTS)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     assert_last_visit_matches(loader.storage, URL, status="full", type="tar")
 
     expected_revision_id = hash_to_bytes("44183488c0774ce3c957fa19ba695cf18a4a42b3")
     revision = list(loader.storage.revision_get([expected_revision_id]))[0]
 
     assert revision is not None
 
     check_metadata_paths(
         revision["metadata"],
         paths=[
             ("intrinsic", dict),
             ("extrinsic.provider", str),
             ("extrinsic.when", str),
             ("extrinsic.raw", dict),
             ("original_artifact", list),
         ],
     )
 
     for original_artifact in revision["metadata"]["original_artifact"]:
         check_metadata_paths(
             original_artifact,
             paths=[("filename", str), ("length", int), ("checksums", dict),],
         )
 
 
 def test_visit_with_release_artifact_no_prior_visit(swh_config, requests_mock_datadir):
     """With no prior visit, load a gnu project ends up with 1 snapshot
 
     """
     loader = ArchiveLoader(url=URL, artifacts=GNU_ARTIFACTS)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert (
         actual_load_status["snapshot_id"] == _expected_new_snapshot_first_visit_id
     )  # noqa
 
     assert_last_visit_matches(loader.storage, URL, status="full", type="tar")
 
     stats = get_stats(loader.storage)
     assert {
         "content": len(_expected_new_contents_first_visit),
         "directory": len(_expected_new_directories_first_visit),
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit),
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_contents = map(hash_to_bytes, _expected_new_contents_first_visit)
     assert list(loader.storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(hash_to_bytes, _expected_new_directories_first_visit)
     assert list(loader.storage.directory_missing(expected_dirs)) == []
 
     expected_revs = map(hash_to_bytes, _expected_new_revisions_first_visit)
     assert list(loader.storage.revision_missing(expected_revs)) == []
 
     expected_snapshot = {
         "id": _expected_new_snapshot_first_visit_id,
         "branches": _expected_branches_first_visit,
     }
 
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_2_visits_without_change(swh_config, requests_mock_datadir):
     """With no prior visit, load a gnu project ends up with 1 snapshot
 
     """
     url = URL
     loader = ArchiveLoader(url, artifacts=GNU_ARTIFACTS)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "uneventful"
     assert actual_load_status2["snapshot_id"] is not None
     assert actual_load_status["snapshot_id"] == actual_load_status2["snapshot_id"]
 
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith("https://ftp.gnu.org")
     ]
     assert len(urls) == 1
 
 
 def test_2_visits_with_new_artifact(swh_config, requests_mock_datadir):
     """With no prior visit, load a gnu project ends up with 1 snapshot
 
     """
     url = URL
     artifact1 = GNU_ARTIFACTS[0]
     loader = ArchiveLoader(url, [artifact1])
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     stats = get_stats(loader.storage)
     assert {
         "content": len(_expected_new_contents_first_visit),
         "directory": len(_expected_new_directories_first_visit),
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit),
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith("https://ftp.gnu.org")
     ]
     assert len(urls) == 1
 
     artifact2 = {
         "time": 1480991830,
         "url": "https://ftp.gnu.org/gnu/8sync/8sync-0.2.0.tar.gz",
         "length": 238466,
         "filename": "8sync-0.2.0.tar.gz",
         "version": "0.2.0",
     }
 
     loader2 = ArchiveLoader(url, [artifact1, artifact2])
     # implementation detail: share the storage in between visits
     loader2.storage = loader.storage
     stats2 = get_stats(loader2.storage)
     assert stats == stats2  # ensure we share the storage
 
     actual_load_status2 = loader2.load()
     assert actual_load_status2["status"] == "eventful"
     assert actual_load_status2["snapshot_id"] is not None
 
     stats2 = get_stats(loader.storage)
     assert {
         "content": len(_expected_new_contents_first_visit) + 14,
         "directory": len(_expected_new_directories_first_visit) + 8,
         "origin": 1,
         "origin_visit": 1 + 1,
         "person": 1,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit) + 1,
         "skipped_content": 0,
         "snapshot": 1 + 1,
     } == stats2
 
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith("https://ftp.gnu.org")
     ]
     # 1 artifact (2nd time no modification) + 1 new artifact
     assert len(urls) == 2
 
 
 def test_2_visits_without_change_not_gnu(swh_config, requests_mock_datadir):
     """Load a project archive (not gnu) ends up with 1 snapshot
 
     """
     url = "https://something.else.org/8sync/"
     artifacts = [  # this is not a gnu artifact
         {
             "time": "1999-12-09T09:53:30+00:00",  # it's also not a timestamp
             "sha256": "d5d1051e59b2be6f065a9fc6aedd3a391e44d0274b78b9bb4e2b57a09134dbe4",  # noqa
             # keep a gnu artifact reference to avoid adding other test files
             "url": "https://ftp.gnu.org/gnu/8sync/8sync-0.2.0.tar.gz",
             "length": 238466,
             "filename": "8sync-0.2.0.tar.gz",
             "version": "0.2.0",
         }
     ]
 
     # Here the loader defines the id_keys to use for existence in the snapshot
     # It's not the default archive loader which
     loader = ArchiveLoader(
         url, artifacts=artifacts, identity_artifact_keys=["sha256", "length", "url"]
     )
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "uneventful"
     assert actual_load_status2["snapshot_id"] == actual_load_status["snapshot_id"]
     assert_last_visit_matches(loader.storage, url, status="full", type="tar")
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith("https://ftp.gnu.org")
     ]
     assert len(urls) == 1
diff --git a/swh/loader/package/cran/tests/test_cran.py b/swh/loader/package/cran/tests/test_cran.py
index 6f56c49..b200663 100644
--- a/swh/loader/package/cran/tests/test_cran.py
+++ b/swh/loader/package/cran/tests/test_cran.py
@@ -1,326 +1,327 @@
 # Copyright (C) 2019-2020 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
 
 from datetime import datetime, timezone
 from dateutil.tz import tzlocal
 
 from os import path
 
 from swh.loader.package.cran.loader import (
     extract_intrinsic_metadata,
     CRANLoader,
     parse_date,
     parse_debian_control,
 )
 from swh.core.tarball import uncompress
+from swh.model.hashutil import hash_to_bytes
 from swh.model.model import TimestampWithTimezone
 
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 
 def test_cran_parse_date():
     data = [
         # parsable, some have debatable results though
         ("2001-June-08", datetime(2001, 6, 8, 0, 0, tzinfo=timezone.utc)),
         (
             "Tue Dec 27 15:06:08 PST 2011",
             datetime(2011, 12, 27, 15, 6, 8, tzinfo=timezone.utc),
         ),
         ("8-14-2013", datetime(2013, 8, 14, 0, 0, tzinfo=timezone.utc)),
         ("2011-01", datetime(2011, 1, 1, 0, 0, tzinfo=timezone.utc)),
         ("201109", datetime(2009, 11, 20, 0, 0, tzinfo=timezone.utc)),
         ("04-12-2014", datetime(2014, 4, 12, 0, 0, tzinfo=timezone.utc)),
         (
             "2018-08-24, 10:40:10",
             datetime(2018, 8, 24, 10, 40, 10, tzinfo=timezone.utc),
         ),
         ("2013-October-16", datetime(2013, 10, 16, 0, 0, tzinfo=timezone.utc)),
         ("Aug 23, 2013", datetime(2013, 8, 23, 0, 0, tzinfo=timezone.utc)),
         ("27-11-2014", datetime(2014, 11, 27, 0, 0, tzinfo=timezone.utc)),
         ("2019-09-26,", datetime(2019, 9, 26, 0, 0, tzinfo=timezone.utc)),
         ("9/25/2014", datetime(2014, 9, 25, 0, 0, tzinfo=timezone.utc)),
         (
             "Fri Jun 27 17:23:53 2014",
             datetime(2014, 6, 27, 17, 23, 53, tzinfo=timezone.utc),
         ),
         ("28-04-2014", datetime(2014, 4, 28, 0, 0, tzinfo=timezone.utc)),
         ("04-14-2014", datetime(2014, 4, 14, 0, 0, tzinfo=timezone.utc)),
         (
             "2019-05-08 14:17:31 UTC",
             datetime(2019, 5, 8, 14, 17, 31, tzinfo=timezone.utc),
         ),
         (
             "Wed May 21 13:50:39 CEST 2014",
             datetime(2014, 5, 21, 13, 50, 39, tzinfo=tzlocal()),
         ),
         (
             "2018-04-10 00:01:04 KST",
             datetime(2018, 4, 10, 0, 1, 4, tzinfo=timezone.utc),
         ),
         ("2019-08-25 10:45", datetime(2019, 8, 25, 10, 45, tzinfo=timezone.utc)),
         ("March 9, 2015", datetime(2015, 3, 9, 0, 0, tzinfo=timezone.utc)),
         ("Aug. 18, 2012", datetime(2012, 8, 18, 0, 0, tzinfo=timezone.utc)),
         ("2014-Dec-17", datetime(2014, 12, 17, 0, 0, tzinfo=timezone.utc)),
         ("March 01, 2013", datetime(2013, 3, 1, 0, 0, tzinfo=timezone.utc)),
         ("2017-04-08.", datetime(2017, 4, 8, 0, 0, tzinfo=timezone.utc)),
         ("2014-Apr-22", datetime(2014, 4, 22, 0, 0, tzinfo=timezone.utc)),
         (
             "Mon Jan 12 19:54:04 2015",
             datetime(2015, 1, 12, 19, 54, 4, tzinfo=timezone.utc),
         ),
         ("May 22, 2014", datetime(2014, 5, 22, 0, 0, tzinfo=timezone.utc)),
         (
             "2014-08-12 09:55:10 EDT",
             datetime(2014, 8, 12, 9, 55, 10, tzinfo=timezone.utc),
         ),
         # unparsable
         ("Fabruary 21, 2012", None),
         ('2019-05-28"', None),
         ("2017-03-01 today", None),
         ("2016-11-0110.1093/icesjms/fsw182", None),
         ("2019-07-010", None),
         ("2015-02.23", None),
         ("20013-12-30", None),
         ("2016-08-017", None),
         ("2019-02-07l", None),
         ("2018-05-010", None),
         ("2019-09-27 KST", None),
         ("$Date$", None),
         ("2019-09-27 KST", None),
         ("2019-06-22 $Date$", None),
         ("$Date: 2013-01-18 12:49:03 -0600 (Fri, 18 Jan 2013) $", None),
         ("2015-7-013", None),
         ("2018-05-023", None),
         ("Check NEWS file for changes: news(package='simSummary')", None),
     ]
     for date, expected_date in data:
         actual_tstz = parse_date(date)
         if expected_date is None:
             assert actual_tstz is None, date
         else:
             expected_tstz = TimestampWithTimezone.from_datetime(expected_date)
             assert actual_tstz == expected_tstz, date
 
 
 @pytest.mark.fs
 def test_extract_intrinsic_metadata(tmp_path, datadir):
     """Parsing existing archive's PKG-INFO should yield results"""
     uncompressed_archive_path = str(tmp_path)
     # sample url
     # https://cran.r-project.org/src_contrib_1.4.0_Recommended_KernSmooth_2.22-6.tar.gz  # noqa
     archive_path = path.join(
         datadir,
         "https_cran.r-project.org",
         "src_contrib_1.4.0_Recommended_KernSmooth_2.22-6.tar.gz",
     )
     uncompress(archive_path, dest=uncompressed_archive_path)
 
     actual_metadata = extract_intrinsic_metadata(uncompressed_archive_path)
 
     expected_metadata = {
         "Package": "KernSmooth",
         "Priority": "recommended",
         "Version": "2.22-6",
         "Date": "2001-June-08",
         "Title": "Functions for kernel smoothing for Wand & Jones (1995)",
         "Author": "S original by Matt Wand.\n\tR port by  Brian Ripley <ripley@stats.ox.ac.uk>.",  # noqa
         "Maintainer": "Brian Ripley <ripley@stats.ox.ac.uk>",
         "Description": 'functions for kernel smoothing (and density estimation)\n  corresponding to the book: \n  Wand, M.P. and Jones, M.C. (1995) "Kernel Smoothing".',  # noqa
         "License": "Unlimited use and distribution (see LICENCE).",
         "URL": "http://www.biostat.harvard.edu/~mwand",
     }
 
     assert actual_metadata == expected_metadata
 
 
 @pytest.mark.fs
 def test_extract_intrinsic_metadata_failures(tmp_path):
     """Parsing inexistent path/archive/PKG-INFO yield None"""
     # inexistent first level path
     assert extract_intrinsic_metadata("/something-inexistent") == {}
     # inexistent second level path (as expected by pypi archives)
     assert extract_intrinsic_metadata(tmp_path) == {}
     # inexistent PKG-INFO within second level path
     existing_path_no_pkginfo = str(tmp_path / "something")
     os.mkdir(existing_path_no_pkginfo)
     assert extract_intrinsic_metadata(tmp_path) == {}
 
 
 def test_cran_one_visit(swh_config, requests_mock_datadir):
     version = "2.22-6"
     base_url = "https://cran.r-project.org"
     origin_url = f"{base_url}/Packages/Recommended_KernSmooth/index.html"
     artifact_url = (
         f"{base_url}/src_contrib_1.4.0_Recommended_KernSmooth_{version}.tar.gz"  # noqa
     )
     loader = CRANLoader(
         origin_url, artifacts=[{"url": artifact_url, "version": version,}]
     )
 
     actual_load_status = loader.load()
 
     expected_snapshot_id = "920adcccc78aaeedd3cfa4459dd900d8c3431a21"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "HEAD": {"target": f"releases/{version}", "target_type": "alias"},
-            f"releases/{version}": {
-                "target": "42bdb16facd5140424359c8ce89a28ecfa1ce603",
+            b"HEAD": {"target": b"releases/2.22-6", "target_type": "alias"},
+            b"releases/2.22-6": {
+                "target": hash_to_bytes("42bdb16facd5140424359c8ce89a28ecfa1ce603"),
                 "target_type": "revision",
             },
         },
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, origin_url, status="full", type="cran")
 
     visit_stats = get_stats(loader.storage)
     assert {
         "content": 33,
         "directory": 7,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == visit_stats
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith(base_url)
     ]
     # visited each artifact once across 2 visits
     assert len(urls) == 1
 
 
 def test_cran_2_visits_same_origin(swh_config, requests_mock_datadir):
     """Multiple visits on the same origin, only 1 archive fetch"""
     version = "2.22-6"
     base_url = "https://cran.r-project.org"
     origin_url = f"{base_url}/Packages/Recommended_KernSmooth/index.html"
     artifact_url = (
         f"{base_url}/src_contrib_1.4.0_Recommended_KernSmooth_{version}.tar.gz"  # noqa
     )
     loader = CRANLoader(
         origin_url, artifacts=[{"url": artifact_url, "version": version}]
     )
 
     # first visit
     actual_load_status = loader.load()
 
     expected_snapshot_id = "920adcccc78aaeedd3cfa4459dd900d8c3431a21"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "HEAD": {"target": f"releases/{version}", "target_type": "alias"},
-            f"releases/{version}": {
-                "target": "42bdb16facd5140424359c8ce89a28ecfa1ce603",
+            b"HEAD": {"target": b"releases/2.22-6", "target_type": "alias"},
+            b"releases/2.22-6": {
+                "target": hash_to_bytes("42bdb16facd5140424359c8ce89a28ecfa1ce603"),
                 "target_type": "revision",
             },
         },
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, origin_url, status="full", type="cran")
 
     visit_stats = get_stats(loader.storage)
     assert {
         "content": 33,
         "directory": 7,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == visit_stats
 
     # second visit
     actual_load_status2 = loader.load()
 
     assert actual_load_status2 == {
         "status": "uneventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, origin_url, status="full", type="cran")
 
     visit_stats2 = get_stats(loader.storage)
     visit_stats["origin_visit"] += 1
     assert visit_stats2 == visit_stats, "same stats as 1st visit, +1 visit"
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith(base_url)
     ]
     assert len(urls) == 1, "visited one time artifact url (across 2 visits)"
 
 
 def test_parse_debian_control(datadir):
     description_file = os.path.join(datadir, "description", "acepack")
 
     actual_metadata = parse_debian_control(description_file)
 
     assert actual_metadata == {
         "Package": "acepack",
         "Maintainer": "Shawn Garbett",
         "Version": "1.4.1",
         "Author": "Phil Spector, Jerome Friedman, Robert Tibshirani...",
         "Description": "Two nonparametric methods for multiple regression...",
         "Title": "ACE & AVAS 4 Selecting Multiple Regression Transformations",
         "License": "MIT + file LICENSE",
         "Suggests": "testthat",
         "Packaged": "2016-10-28 15:38:59 UTC; garbetsp",
         "Repository": "CRAN",
         "Date/Publication": "2016-10-29 00:11:52",
         "NeedsCompilation": "yes",
     }
 
 
 def test_parse_debian_control_unicode_issue(datadir):
     # iso-8859-1 caused failure, now fixed
     description_file = os.path.join(datadir, "description", "KnownBR")
 
     actual_metadata = parse_debian_control(description_file)
 
     assert actual_metadata == {
         "Package": "KnowBR",
         "Version": "2.0",
         "Title": """Discriminating Well Surveyed Spatial Units from Exhaustive
         Biodiversity Databases""",
         "Author": "Cástor Guisande González and Jorge M. Lobo",
         "Maintainer": "Cástor Guisande González <castor@email.es>",
         "Description": "It uses species accumulation curves and diverse estimators...",
         "License": "GPL (>= 2)",
         "Encoding": "latin1",
         "Depends": "R (>= 3.0), fossil, mgcv, plotrix, sp, vegan",
         "Suggests": "raster, rgbif",
         "NeedsCompilation": "no",
         "Packaged": "2019-01-30 13:27:29 UTC; castor",
         "Repository": "CRAN",
         "Date/Publication": "2019-01-31 20:53:50 UTC",
     }
diff --git a/swh/loader/package/debian/tests/test_debian.py b/swh/loader/package/debian/tests/test_debian.py
index 28eb14f..d6aebca 100644
--- a/swh/loader/package/debian/tests/test_debian.py
+++ b/swh/loader/package/debian/tests/test_debian.py
@@ -1,466 +1,467 @@
 # Copyright (C) 2019-2020  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 copy
 import logging
 import pytest
 import random
 
 from os import path
 
 from swh.loader.package.debian.loader import (
     DebianLoader,
     download_package,
     dsc_information,
     uid_to_person,
     prepare_person,
     get_package_metadata,
     extract_package,
 )
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 from swh.loader.package.debian.loader import resolve_revision_from
 
+from swh.model.hashutil import hash_to_bytes
 from swh.model.model import Person
 
 
 logger = logging.getLogger(__name__)
 
 
 PACKAGE_FILES = {
     "name": "cicero",
     "version": "0.7.2-3",
     "files": {
         "cicero_0.7.2-3.diff.gz": {
             "md5sum": "a93661b6a48db48d59ba7d26796fc9ce",
             "name": "cicero_0.7.2-3.diff.gz",
             "sha256": "f039c9642fe15c75bed5254315e2a29f9f2700da0e29d9b0729b3ffc46c8971c",  # noqa
             "size": 3964,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2-3.diff.gz",  # noqa
         },
         "cicero_0.7.2-3.dsc": {
             "md5sum": "d5dac83eb9cfc9bb52a15eb618b4670a",
             "name": "cicero_0.7.2-3.dsc",
             "sha256": "35b7f1048010c67adfd8d70e4961aefd8800eb9a83a4d1cc68088da0009d9a03",  # noqa
             "size": 1864,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2-3.dsc",  # noqa
         },  # noqa
         "cicero_0.7.2.orig.tar.gz": {
             "md5sum": "4353dede07c5728319ba7f5595a7230a",
             "name": "cicero_0.7.2.orig.tar.gz",
             "sha256": "63f40f2436ea9f67b44e2d4bd669dbabe90e2635a204526c20e0b3c8ee957786",  # noqa
             "size": 96527,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2.orig.tar.gz",  # noqa
         },
     },
 }
 
 PACKAGE_FILES2 = {
     "name": "cicero",
     "version": "0.7.2-4",
     "files": {
         "cicero_0.7.2-4.diff.gz": {
             "md5sum": "1e7e6fc4a59d57c98082a3af78145734",
             "name": "cicero_0.7.2-4.diff.gz",
             "sha256": "2e6fa296ee7005473ff58d0971f4fd325617b445671480e9f2cfb738d5dbcd01",  # noqa
             "size": 4038,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2-4.diff.gz",  # noqa
         },
         "cicero_0.7.2-4.dsc": {
             "md5sum": "1a6c8855a73b4282bb31d15518f18cde",
             "name": "cicero_0.7.2-4.dsc",
             "sha256": "913ee52f7093913420de5cbe95d63cfa817f1a1daf997961149501894e754f8b",  # noqa
             "size": 1881,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2-4.dsc",  # noqa
         },  # noqa
         "cicero_0.7.2.orig.tar.gz": {
             "md5sum": "4353dede07c5728319ba7f5595a7230a",
             "name": "cicero_0.7.2.orig.tar.gz",
             "sha256": "63f40f2436ea9f67b44e2d4bd669dbabe90e2635a204526c20e0b3c8ee957786",  # noqa
             "size": 96527,
             "uri": "http://deb.debian.org/debian/pool/contrib/c/cicero/cicero_0.7.2.orig.tar.gz",  # noqa
         },
     },
 }
 
 
 PACKAGE_PER_VERSION = {
     "stretch/contrib/0.7.2-3": PACKAGE_FILES,
 }
 
 
 PACKAGES_PER_VERSION = {
     "stretch/contrib/0.7.2-3": PACKAGE_FILES,
     "buster/contrib/0.7.2-4": PACKAGE_FILES2,
 }
 
 
 def test_debian_first_visit(swh_config, requests_mock_datadir):
     """With no prior visit, load a gnu project ends up with 1 snapshot
 
     """
     url = "deb://Debian/packages/cicero"
     loader = DebianLoader(
         url=url, date="2019-10-12T05:58:09.165557+00:00", packages=PACKAGE_PER_VERSION,
     )
 
     actual_load_status = loader.load()
     expected_snapshot_id = "3b6b66e6ee4e7d903a379a882684a2a50480c0b4"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="deb")
 
     stats = get_stats(loader.storage)
     assert {
         "content": 42,
         "directory": 2,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,  # all artifacts under 1 revision
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "releases/stretch/contrib/0.7.2-3": {
+            b"releases/stretch/contrib/0.7.2-3": {
                 "target_type": "revision",
-                "target": "2807f5b3f84368b4889a9ae827fe85854ffecf07",
+                "target": hash_to_bytes("2807f5b3f84368b4889a9ae827fe85854ffecf07"),
             }
         },
     }  # different than the previous loader as no release is done
 
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_debian_first_visit_then_another_visit(swh_config, requests_mock_datadir):
     """With no prior visit, load a debian project ends up with 1 snapshot
 
     """
     url = "deb://Debian/packages/cicero"
     loader = DebianLoader(
         url=url, date="2019-10-12T05:58:09.165557+00:00", packages=PACKAGE_PER_VERSION
     )
 
     actual_load_status = loader.load()
 
     expected_snapshot_id = "3b6b66e6ee4e7d903a379a882684a2a50480c0b4"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="deb")
 
     stats = get_stats(loader.storage)
     assert {
         "content": 42,
         "directory": 2,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,  # all artifacts under 1 revision
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "releases/stretch/contrib/0.7.2-3": {
+            b"releases/stretch/contrib/0.7.2-3": {
                 "target_type": "revision",
-                "target": "2807f5b3f84368b4889a9ae827fe85854ffecf07",
+                "target": hash_to_bytes("2807f5b3f84368b4889a9ae827fe85854ffecf07"),
             }
         },
     }  # different than the previous loader as no release is done
 
     check_snapshot(expected_snapshot, loader.storage)
 
     # No change in between load
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "uneventful"
     assert_last_visit_matches(loader.storage, url, status="full", type="deb")
 
     stats2 = get_stats(loader.storage)
     assert {
         "content": 42 + 0,
         "directory": 2 + 0,
         "origin": 1,
         "origin_visit": 1 + 1,  # a new visit occurred
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,  # same snapshot across 2 visits
     } == stats2
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url.startswith("http://deb.debian.org")
     ]
     # visited each package artifact twice across 2 visits
     assert len(urls) == len(set(urls))
 
 
 def test_uid_to_person():
     uid = "Someone Name <someone@orga.org>"
     actual_person = uid_to_person(uid)
 
     assert actual_person == {
         "name": "Someone Name",
         "email": "someone@orga.org",
         "fullname": uid,
     }
 
 
 def test_prepare_person():
     actual_author = prepare_person(
         {
             "name": "Someone Name",
             "email": "someone@orga.org",
             "fullname": "Someone Name <someone@orga.org>",
         }
     )
 
     assert actual_author == Person(
         name=b"Someone Name",
         email=b"someone@orga.org",
         fullname=b"Someone Name <someone@orga.org>",
     )
 
 
 def test_download_package(datadir, tmpdir, requests_mock_datadir):
     tmpdir = str(tmpdir)  # py3.5 work around (LocalPath issue)
     all_hashes = download_package(PACKAGE_FILES, tmpdir)
     assert all_hashes == {
         "cicero_0.7.2-3.diff.gz": {
             "checksums": {
                 "sha1": "0815282053f21601b0ec4adf7a8fe47eace3c0bc",
                 "sha256": "f039c9642fe15c75bed5254315e2a29f9f2700da0e29d9b0729b3ffc46c8971c",  # noqa
             },
             "filename": "cicero_0.7.2-3.diff.gz",
             "length": 3964,
         },
         "cicero_0.7.2-3.dsc": {
             "checksums": {
                 "sha1": "abbec4e8efbbc80278236e1dd136831eac08accd",
                 "sha256": "35b7f1048010c67adfd8d70e4961aefd8800eb9a83a4d1cc68088da0009d9a03",  # noqa
             },
             "filename": "cicero_0.7.2-3.dsc",
             "length": 1864,
         },
         "cicero_0.7.2.orig.tar.gz": {
             "checksums": {
                 "sha1": "a286efd63fe2c9c9f7bb30255c3d6fcdcf390b43",
                 "sha256": "63f40f2436ea9f67b44e2d4bd669dbabe90e2635a204526c20e0b3c8ee957786",  # noqa
             },
             "filename": "cicero_0.7.2.orig.tar.gz",
             "length": 96527,
         },
     }
 
 
 def test_dsc_information_ok():
     fname = "cicero_0.7.2-3.dsc"
     dsc_url, dsc_name = dsc_information(PACKAGE_FILES)
 
     assert dsc_url == PACKAGE_FILES["files"][fname]["uri"]
     assert dsc_name == PACKAGE_FILES["files"][fname]["name"]
 
 
 def test_dsc_information_not_found():
     fname = "cicero_0.7.2-3.dsc"
     package_files = copy.deepcopy(PACKAGE_FILES)
     package_files["files"].pop(fname)
 
     dsc_url, dsc_name = dsc_information(package_files)
 
     assert dsc_url is None
     assert dsc_name is None
 
 
 def test_dsc_information_too_many_dsc_entries():
     # craft an extra dsc file
     fname = "cicero_0.7.2-3.dsc"
     package_files = copy.deepcopy(PACKAGE_FILES)
     data = package_files["files"][fname]
     fname2 = fname.replace("cicero", "ciceroo")
     package_files["files"][fname2] = data
 
     with pytest.raises(
         ValueError,
         match="Package %s_%s references several dsc"
         % (package_files["name"], package_files["version"]),
     ):
         dsc_information(package_files)
 
 
 def test_get_package_metadata(requests_mock_datadir, datadir, tmp_path):
     tmp_path = str(tmp_path)  # py3.5 compat.
     package = PACKAGE_FILES
 
     logger.debug("package: %s", package)
 
     # download the packages
     all_hashes = download_package(package, tmp_path)
 
     # Retrieve information from package
     _, dsc_name = dsc_information(package)
 
     dl_artifacts = [(tmp_path, hashes) for hashes in all_hashes.values()]
 
     # Extract information from package
     extracted_path = extract_package(dl_artifacts, tmp_path)
 
     # Retrieve information on package
     dsc_path = path.join(path.dirname(extracted_path), dsc_name)
     actual_package_info = get_package_metadata(package, dsc_path, extracted_path)
 
     logger.debug("actual_package_info: %s", actual_package_info)
 
     assert actual_package_info == {
         "changelog": {
             "date": "2014-10-19T16:52:35+02:00",
             "history": [
                 ("cicero", "0.7.2-2"),
                 ("cicero", "0.7.2-1"),
                 ("cicero", "0.7-1"),
             ],
             "person": {
                 "email": "sthibault@debian.org",
                 "fullname": "Samuel Thibault <sthibault@debian.org>",
                 "name": "Samuel Thibault",
             },
         },
         "maintainers": [
             {
                 "email": "debian-accessibility@lists.debian.org",
                 "fullname": "Debian Accessibility Team "
                 "<debian-accessibility@lists.debian.org>",
                 "name": "Debian Accessibility Team",
             },
             {
                 "email": "sthibault@debian.org",
                 "fullname": "Samuel Thibault <sthibault@debian.org>",
                 "name": "Samuel Thibault",
             },
         ],
         "name": "cicero",
         "version": "0.7.2-3",
     }
 
 
 def test_debian_multiple_packages(swh_config, requests_mock_datadir):
     url = "deb://Debian/packages/cicero"
     loader = DebianLoader(
         url=url, date="2019-10-12T05:58:09.165557+00:00", packages=PACKAGES_PER_VERSION
     )
 
     actual_load_status = loader.load()
     expected_snapshot_id = "defc19021187f3727293121fcf6c5c82cb923604"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="deb")
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "releases/stretch/contrib/0.7.2-3": {
+            b"releases/stretch/contrib/0.7.2-3": {
                 "target_type": "revision",
-                "target": "2807f5b3f84368b4889a9ae827fe85854ffecf07",
+                "target": hash_to_bytes("2807f5b3f84368b4889a9ae827fe85854ffecf07"),
             },
-            "releases/buster/contrib/0.7.2-4": {
+            b"releases/buster/contrib/0.7.2-4": {
                 "target_type": "revision",
-                "target": "8224139c274c984147ef4b09aa0e462c55a10bd3",
+                "target": hash_to_bytes("8224139c274c984147ef4b09aa0e462c55a10bd3"),
             },
         },
     }
 
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_resolve_revision_from_edge_cases():
     """Solving revision with empty data will result in unknown revision
 
     """
     for package_artifacts in [{}, PACKAGE_FILES]:
         actual_revision = resolve_revision_from(package_artifacts, {})
         assert actual_revision is None
 
     for known_artifacts in [{}, PACKAGE_FILES]:
         actual_revision = resolve_revision_from({}, known_artifacts)
         assert actual_revision is None
 
     known_package_artifacts = {
         b"(\x07\xf5\xb3\xf8Ch\xb4\x88\x9a\x9a\xe8'\xfe\x85\x85O\xfe\xcf\x07": {
             "extrinsic": {
                 # empty
             },
             # ... removed the unnecessary intermediary data
         }
     }
     assert not resolve_revision_from(known_package_artifacts, PACKAGE_FILES)
 
 
 def test_resolve_revision_from_edge_cases_hit_and_miss():
     """Solving revision with inconsistent data will result in unknown revision
 
     """
     artifact_metadata = PACKAGE_FILES2
     expected_revision_id = (
         b"(\x08\xf5\xb3\xf8Ch\xb4\x88\x9a\x9a\xe8'\xff\x85\x85O\xfe\xcf\x07"  # noqa
     )
     known_package_artifacts = {
         expected_revision_id: {
             "extrinsic": {"raw": PACKAGE_FILES,},
             # ... removed the unnecessary intermediary data
         }
     }
 
     actual_revision = resolve_revision_from(known_package_artifacts, artifact_metadata)
 
     assert actual_revision is None
 
 
 def test_resolve_revision_from():
     """Solving revision with consistent data will solve the revision
 
     """
     artifact_metadata = PACKAGE_FILES
     expected_revision_id = (
         b"(\x07\xf5\xb3\xf8Ch\xb4\x88\x9a\x9a\xe8'\xfe\x85\x85O\xfe\xcf\x07"  # noqa
     )
 
     files = artifact_metadata["files"]
     # shuffling dict's keys
     keys = list(files.keys())
     random.shuffle(keys)
     package_files = {"files": {k: files[k] for k in keys}}
 
     known_package_artifacts = {
         expected_revision_id: {
             "extrinsic": {"raw": package_files,},
             # ... removed the unnecessary intermediary data
         }
     }
 
     actual_revision = resolve_revision_from(known_package_artifacts, artifact_metadata)
 
     assert actual_revision == expected_revision_id
diff --git a/swh/loader/package/deposit/tests/test_deposit.py b/swh/loader/package/deposit/tests/test_deposit.py
index d7062d3..b373b2d 100644
--- a/swh/loader/package/deposit/tests/test_deposit.py
+++ b/swh/loader/package/deposit/tests/test_deposit.py
@@ -1,367 +1,369 @@
 # Copyright (C) 2019-2020  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 re
 
 import pytest
 
 from swh.model.hashutil import hash_to_bytes, hash_to_hex
 from swh.loader.package.deposit.loader import DepositLoader
 
 from swh.loader.package.tests.common import check_metadata_paths
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 from swh.core.pytest_plugin import requests_mock_datadir_factory
 
 
 DEPOSIT_URL = "https://deposit.softwareheritage.org/1/private"
 
 
 @pytest.fixture
 def requests_mock_datadir(requests_mock_datadir):
     """Enhance default mock data to mock put requests as the loader does some
        internal update queries there.
 
     """
     requests_mock_datadir.put(re.compile("https"))
     return requests_mock_datadir
 
 
 def test_deposit_init_ok(swh_config, swh_loader_config):
     url = "some-url"
     deposit_id = 999
     loader = DepositLoader(url, deposit_id)  # Something that does not exist
 
     assert loader.url == url
     assert loader.client is not None
     assert loader.client.base_url == swh_loader_config["deposit"]["url"]
 
 
 def test_deposit_loading_unknown_deposit(swh_config, requests_mock_datadir):
     """Loading an unknown deposit should fail
 
     no origin, no visit, no snapshot
     """
     # private api url form: 'https://deposit.s.o/1/private/hal/666/raw/'
     url = "some-url"
     unknown_deposit_id = 667
     loader = DepositLoader(url, unknown_deposit_id)  # does not exist
 
     actual_load_status = loader.load()
     assert actual_load_status == {"status": "failed"}
 
     stats = get_stats(loader.storage)
 
     assert {
         "content": 0,
         "directory": 0,
         "origin": 0,
         "origin_visit": 0,
         "person": 0,
         "release": 0,
         "revision": 0,
         "skipped_content": 0,
         "snapshot": 0,
     } == stats
 
 
 requests_mock_datadir_missing_one = requests_mock_datadir_factory(
     ignore_urls=[f"{DEPOSIT_URL}/666/raw/",]
 )
 
 
 def test_deposit_loading_failure_to_retrieve_1_artifact(
     swh_config, requests_mock_datadir_missing_one
 ):
     """Deposit with missing artifact ends up with an uneventful/partial visit
 
     """
     # private api url form: 'https://deposit.s.o/1/private/hal/666/raw/'
     url = "some-url-2"
     deposit_id = 666
     loader = DepositLoader(url, deposit_id)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
     assert actual_load_status["snapshot_id"] is not None
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="deposit")
 
     stats = get_stats(loader.storage)
     assert {
         "content": 0,
         "directory": 0,
         "origin": 1,
         "origin_visit": 1,
         "person": 0,
         "release": 0,
         "revision": 0,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
 
 def test_revision_metadata_structure(swh_config, requests_mock_datadir):
     url = "https://hal-test.archives-ouvertes.fr/some-external-id"
     deposit_id = 666
     loader = DepositLoader(url, deposit_id)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
     expected_revision_id = hash_to_bytes("637318680351f5d78856d13264faebbd91efe9bb")
     revision = list(loader.storage.revision_get([expected_revision_id]))[0]
 
     assert revision is not None
 
     check_metadata_paths(
         revision["metadata"],
         paths=[
             ("extrinsic.provider", str),
             ("extrinsic.when", str),
             ("extrinsic.raw", dict),
             ("original_artifact", list),
         ],
     )
 
     # Only 2 top-level keys now
     assert set(revision["metadata"].keys()) == {"extrinsic", "original_artifact"}
 
     for original_artifact in revision["metadata"]["original_artifact"]:
         check_metadata_paths(
             original_artifact,
             paths=[("filename", str), ("length", int), ("checksums", dict),],
         )
 
 
 def test_deposit_loading_ok(swh_config, requests_mock_datadir):
     url = "https://hal-test.archives-ouvertes.fr/some-external-id"
     deposit_id = 666
     loader = DepositLoader(url, deposit_id)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "b2b327b33dc85818bd23c3ccda8b7e675a66ecbd"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="deposit")
 
     stats = get_stats(loader.storage)
     assert {
         "content": 303,
         "directory": 12,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     revision_id = "637318680351f5d78856d13264faebbd91efe9bb"
     expected_branches = {
-        "HEAD": {"target": revision_id, "target_type": "revision",},
+        b"HEAD": {"target": hash_to_bytes(revision_id), "target_type": "revision",},
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     check_snapshot(expected_snapshot, storage=loader.storage)
 
     revision = next(loader.storage.revision_get([hash_to_bytes(revision_id)]))
     assert revision
 
     # check metadata
 
     fetcher = {
         "name": "swh-deposit",
         "version": "0.0.1",
     }
 
     authority = {
         "type": "deposit_client",
         "url": "https://hal-test.archives-ouvertes.fr/",
     }
 
     orig_meta = loader.storage.origin_metadata_get(url, authority)
     assert orig_meta is not None
     assert isinstance(orig_meta, dict)
     assert len(orig_meta["results"]) == 1
     assert orig_meta["next_page_token"] is None
     orig_meta0 = orig_meta["results"][0]
 
     assert orig_meta0["authority"] == authority
     assert orig_meta0["fetcher"] == fetcher
 
     # Retrieve the information for deposit status update query to the deposit
     urls = [
         m
         for m in requests_mock_datadir.request_history
         if m.url == f"{DEPOSIT_URL}/{deposit_id}/update/"
     ]
 
     assert len(urls) == 1
     update_query = urls[0]
 
     body = update_query.json()
     expected_body = {
         "status": "done",
         "revision_id": revision_id,
         "directory_id": hash_to_hex(revision["directory"]),
         "snapshot_id": expected_snapshot_id,
         "origin_url": url,
     }
 
     assert body == expected_body
 
 
 def test_deposit_loading_ok_2(swh_config, requests_mock_datadir):
     """Field dates should be se appropriately
 
     """
     external_id = "some-external-id"
     url = f"https://hal-test.archives-ouvertes.fr/{external_id}"
     deposit_id = 777
     loader = DepositLoader(url, deposit_id)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "3e68440fdd7c81d283f8f3aebb6f0c8657864192"
 
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
     assert_last_visit_matches(loader.storage, url, status="full", type="deposit")
 
     revision_id = "564d18943d71be80d0d73b43a77cfb205bcde96c"
-    expected_branches = {"HEAD": {"target": revision_id, "target_type": "revision"}}
+    expected_branches = {
+        b"HEAD": {"target": hash_to_bytes(revision_id), "target_type": "revision"}
+    }
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
 
     check_snapshot(expected_snapshot, storage=loader.storage)
 
     raw_meta = loader.client.metadata_get(deposit_id)
     # Ensure the date fields are set appropriately in the revision
 
     # Retrieve the revision
     revision = next(loader.storage.revision_get([hash_to_bytes(revision_id)]))
     assert revision
     assert revision["date"] == raw_meta["deposit"]["author_date"]
     assert revision["committer_date"] == raw_meta["deposit"]["committer_date"]
 
     read_api = f"{DEPOSIT_URL}/{deposit_id}/meta/"
 
     assert revision["metadata"] == {
         "extrinsic": {
             "provider": read_api,
             "raw": {
                 "origin": {"type": "deposit", "url": url,},
                 "origin_metadata": {
                     "metadata": {
                         "@xmlns": ["http://www.w3.org/2005/Atom"],
                         "author": ["some awesome author", "another one", "no one",],
                         "codemeta:dateCreated": "2017-10-07T15:17:08Z",
                         "codemeta:datePublished": "2017-10-08T15:00:00Z",
                         "external_identifier": "some-external-id",
                         "url": url,
                     },
                     "provider": {
                         "metadata": None,
                         "provider_name": "hal",
                         "provider_type": "deposit_client",
                         "provider_url": "https://hal-test.archives-ouvertes.fr/",
                     },
                     "tool": {
                         "configuration": {"sword_version": "2"},
                         "name": "swh-deposit",
                         "version": "0.0.1",
                     },
                 },
             },
             "when": revision["metadata"]["extrinsic"]["when"],  # dynamic
         },
         "original_artifact": [
             {
                 "checksums": {
                     "sha1": "f8c63d7c890a7453498e6cf9fef215d85ec6801d",
                     "sha256": "474bf646aeeff6d945eb752b1a9f8a40f3d81a88909ee7bd2d08cc822aa361e6",  # noqa
                 },
                 "filename": "archive.zip",
                 "length": 956830,
             }
         ],
     }
 
     fetcher = {
         "name": "swh-deposit",
         "version": "0.0.1",
     }
 
     authority = {
         "type": "deposit_client",
         "url": "https://hal-test.archives-ouvertes.fr/",
     }
 
     # Check the metadata swh side
     orig_meta = loader.storage.origin_metadata_get(url, authority)
     assert orig_meta is not None
     assert isinstance(orig_meta, dict)
     assert len(orig_meta["results"]) == 1
     assert orig_meta["next_page_token"] is None
 
     assert len(orig_meta["results"]) == 1
 
     orig_meta0 = orig_meta["results"][0]
     # dynamic, a pain to display and not that interesting
     orig_meta0.pop("discovery_date")
 
     assert orig_meta0 == {
         "origin_url": "https://hal-test.archives-ouvertes.fr/some-external-id",
         "metadata": json.dumps(
             {
                 "@xmlns": ["http://www.w3.org/2005/Atom"],
                 "author": ["some awesome author", "another one", "no one"],
                 "codemeta:dateCreated": "2017-10-07T15:17:08Z",
                 "codemeta:datePublished": "2017-10-08T15:00:00Z",
                 "external_identifier": "some-external-id",
                 "url": "https://hal-test.archives-ouvertes.fr/some-external-id",
             }
         ).encode(),
         "format": "sword-v2-atom-codemeta-v2-in-json",
         "authority": authority,
         "fetcher": fetcher,
     }
 
     # Retrieve the information for deposit status update query to the deposit
     urls = [
         m
         for m in requests_mock_datadir.request_history
         if m.url == f"{DEPOSIT_URL}/{deposit_id}/update/"
     ]
 
     assert len(urls) == 1
     update_query = urls[0]
 
     body = update_query.json()
     expected_body = {
         "status": "done",
         "revision_id": revision_id,
         "directory_id": hash_to_hex(revision["directory"]),
         "snapshot_id": expected_snapshot_id,
         "origin_url": url,
     }
 
     assert body == expected_body
diff --git a/swh/loader/package/nixguix/tests/test_nixguix.py b/swh/loader/package/nixguix/tests/test_nixguix.py
index 6a5e273..5c28996 100644
--- a/swh/loader/package/nixguix/tests/test_nixguix.py
+++ b/swh/loader/package/nixguix/tests/test_nixguix.py
@@ -1,572 +1,572 @@
 # Copyright (C) 2020 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 json
 import logging
 
 import pytest
 
 from json.decoder import JSONDecodeError
 from swh.storage.interface import StorageInterface
 from typing import Any, Dict, Iterable, Optional, Tuple, Union
 
 from unittest.mock import patch
 
 from swh.model.model import Snapshot, TargetType
 from swh.loader.package.archive.loader import ArchiveLoader
 from swh.loader.package.nixguix.loader import (
     NixGuixLoader,
     retrieve_sources,
     clean_sources,
 )
 
 from swh.loader.package.utils import download
 from swh.model.hashutil import hash_to_bytes, hash_to_hex
 from swh.storage.exc import HashCollision
 
 from swh.loader.tests import (
     assert_last_visit_matches,
     get_stats,
     check_snapshot as check_snapshot_full,
 )
 
 
 sources_url = "https://nix-community.github.io/nixpkgs-swh/sources.json"
 
 
 def check_snapshot(
     snapshot: Union[Dict[str, Any], Snapshot],
     storage: StorageInterface,
     allowed_empty: Iterable[Tuple[TargetType, bytes]] = [
         (TargetType.REVISION, b"evaluation")
     ],
 ):
     return check_snapshot_full(snapshot, storage, allowed_empty)
 
 
 def test_retrieve_sources(swh_config, requests_mock_datadir):
     j = retrieve_sources(sources_url)
     assert "sources" in j.keys()
     assert len(j["sources"]) == 2
 
 
 def test_retrieve_non_existing(swh_config, requests_mock_datadir):
     with pytest.raises(ValueError):
         NixGuixLoader("https://non-existing-url")
 
 
 def test_retrieve_non_json(swh_config, requests_mock_datadir):
     with pytest.raises(JSONDecodeError):
         NixGuixLoader("https://example.com/file.txt")
 
 
 def test_clean_sources_invalid_schema(swh_config, requests_mock_datadir):
     sources = {}
     with pytest.raises(ValueError, match="sources structure invalid, missing: .*"):
         clean_sources(sources)
 
 
 def test_clean_sources_invalid_version(swh_config, requests_mock_datadir):
     for version_ok in [1, "1"]:  # Check those versions are fine
         clean_sources({"version": version_ok, "sources": [], "revision": "my-revision"})
 
     for version_ko in [0, "0", 2, "2"]:  # Check version != 1 raise an error
         with pytest.raises(
             ValueError, match="sources structure version .* is not supported"
         ):
             clean_sources(
                 {"version": version_ko, "sources": [], "revision": "my-revision"}
             )
 
 
 def test_clean_sources_invalid_sources(swh_config, requests_mock_datadir):
     sources = {
         "version": 1,
         "sources": [
             # Valid source
             {"type": "url", "urls": ["my-url"], "integrity": "my-integrity"},
             # integrity is missing
             {"type": "url", "urls": ["my-url"],},
             # urls is not a list
             {"type": "url", "urls": "my-url", "integrity": "my-integrity"},
             # type is not url
             {"type": "git", "urls": ["my-url"], "integrity": "my-integrity"},
             # missing fields which got double-checked nonetheless...
             {"integrity": "my-integrity"},
         ],
         "revision": "my-revision",
     }
     clean = clean_sources(sources)
 
     assert len(clean["sources"]) == 1
 
 
 def check_snapshot_revisions_ok(snapshot, storage):
     """Ensure the snapshot revisions are structurally as expected
 
     """
     revision_ids = []
     for name, branch in snapshot["branches"].items():
         if name == b"evaluation":
             continue  # skipping that particular branch
         if branch["target_type"] == "revision":
             revision_ids.append(branch["target"])
 
     revisions = storage.revision_get(revision_ids)
     for rev in revisions:
         metadata = rev["metadata"]
         raw = metadata["extrinsic"]["raw"]
         assert "url" in raw
         assert "integrity" in raw
 
 
 def test_loader_one_visit(swh_config, requests_mock_datadir):
     loader = NixGuixLoader(sources_url)
     res = loader.load()
     assert res["status"] == "eventful"
 
     stats = get_stats(loader.storage)
     assert {
         "content": 1,
         "directory": 3,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     # The visit is partial because urls pointing to non tarball file
     # are not handled yet
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
 
 def test_uncompress_failure(swh_config, requests_mock_datadir):
     """Non tarball files are currently not supported and the uncompress
     function fails on such kind of files.
 
     However, even in this case of failure (because of the url
     https://example.com/file.txt), a snapshot and a visit has to be
     created (with a status partial since all files are not archived).
 
     """
     loader = NixGuixLoader(sources_url)
     loader_status = loader.load()
 
     urls = [s["urls"][0] for s in loader.sources]
     assert "https://example.com/file.txt" in urls
     assert loader_status["status"] == "eventful"
 
     # The visit is partial because urls pointing to non tarball files
     # are not handled yet
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
 
 def test_loader_incremental(swh_config, requests_mock_datadir):
     """Ensure a second visit do not download artifact already
     downloaded by the previous visit.
 
     """
     loader = NixGuixLoader(sources_url)
     load_status = loader.load()
 
     loader.load()
     expected_snapshot_id = "0c5881c74283793ebe9a09a105a9381e41380383"
     assert load_status == {"status": "eventful", "snapshot_id": expected_snapshot_id}
 
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
     expected_branches = {
-        "evaluation": {
-            "target": "cc4e04c26672dd74e5fd0fecb78b435fb55368f7",
+        b"evaluation": {
+            "target": hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             "target_type": "revision",
         },
-        "https://github.com/owner-1/repository-1/revision-1.tgz": {
-            "target": "488ad4e7b8e2511258725063cf43a2b897c503b4",
+        b"https://github.com/owner-1/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("488ad4e7b8e2511258725063cf43a2b897c503b4"),
             "target_type": "revision",
         },
     }
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
     urls = [
         m.url
         for m in requests_mock_datadir.request_history
         if m.url == ("https://github.com/owner-1/repository-1/revision-1.tgz")
     ]
     # The artifact
     # 'https://github.com/owner-1/repository-1/revision-1.tgz' is only
     # visited one time
     assert len(urls) == 1
 
 
 def test_loader_two_visits(swh_config, requests_mock_datadir_visits):
     """To ensure there is only one origin, but two visits, two revisions
     and two snapshots are created.
 
     The first visit creates a snapshot containing one tarball. The
     second visit creates a snapshot containing the same tarball and
     another tarball.
 
     """
     loader = NixGuixLoader(sources_url)
     load_status = loader.load()
     expected_snapshot_id = "0c5881c74283793ebe9a09a105a9381e41380383"
     assert load_status == {"status": "eventful", "snapshot_id": expected_snapshot_id}
 
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
     expected_branches = {
-        "evaluation": {
-            "target": "cc4e04c26672dd74e5fd0fecb78b435fb55368f7",
+        b"evaluation": {
+            "target": hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             "target_type": "revision",
         },
-        "https://github.com/owner-1/repository-1/revision-1.tgz": {
-            "target": "488ad4e7b8e2511258725063cf43a2b897c503b4",
+        b"https://github.com/owner-1/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("488ad4e7b8e2511258725063cf43a2b897c503b4"),
             "target_type": "revision",
         },
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
     stats = get_stats(loader.storage)
     assert {
         "content": 1,
         "directory": 3,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     loader = NixGuixLoader(sources_url)
     load_status = loader.load()
     expected_snapshot_id = "b0bfa75cbd0cc90aac3b9e95fb0f59c731176d97"
     assert load_status == {"status": "eventful", "snapshot_id": expected_snapshot_id}
 
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
     # This ensures visits are incremental. Indeed, if we request a
     # second time an url, because of the requests_mock_datadir_visits
     # fixture, the file has to end with `_visit1`.
     expected_branches = {
-        "evaluation": {
-            "target": "602140776b2ce6c9159bcf52ada73a297c063d5e",
+        b"evaluation": {
+            "target": hash_to_bytes("602140776b2ce6c9159bcf52ada73a297c063d5e"),
             "target_type": "revision",
         },
-        "https://github.com/owner-1/repository-1/revision-1.tgz": {
-            "target": "488ad4e7b8e2511258725063cf43a2b897c503b4",
+        b"https://github.com/owner-1/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("488ad4e7b8e2511258725063cf43a2b897c503b4"),
             "target_type": "revision",
         },
-        "https://github.com/owner-2/repository-1/revision-1.tgz": {
-            "target": "85e0bad74e33e390aaeb74f139853ae3863ee544",
+        b"https://github.com/owner-2/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("85e0bad74e33e390aaeb74f139853ae3863ee544"),
             "target_type": "revision",
         },
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
     stats = get_stats(loader.storage)
     assert {
         "content": 2,
         "directory": 5,
         "origin": 1,
         "origin_visit": 2,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 2,
     } == stats
 
 
 def test_resolve_revision_from(swh_config, requests_mock_datadir):
     loader = NixGuixLoader(sources_url)
 
     known_artifacts = {
         "id1": {"extrinsic": {"raw": {"url": "url1", "integrity": "integrity1"}}},
         "id2": {"extrinsic": {"raw": {"url": "url2", "integrity": "integrity2"}}},
     }
 
     metadata = {"url": "url1", "integrity": "integrity1"}
     assert loader.resolve_revision_from(known_artifacts, metadata) == "id1"
     metadata = {"url": "url3", "integrity": "integrity3"}
     assert loader.resolve_revision_from(known_artifacts, metadata) == None  # noqa
 
 
 def test_evaluation_branch(swh_config, requests_mock_datadir):
     loader = NixGuixLoader(sources_url)
     res = loader.load()
     assert res["status"] == "eventful"
 
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
     expected_branches = {
-        "https://github.com/owner-1/repository-1/revision-1.tgz": {
-            "target": "488ad4e7b8e2511258725063cf43a2b897c503b4",
+        b"https://github.com/owner-1/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("488ad4e7b8e2511258725063cf43a2b897c503b4"),
             "target_type": "revision",
         },
-        "evaluation": {
-            "target": "cc4e04c26672dd74e5fd0fecb78b435fb55368f7",
+        b"evaluation": {
+            "target": hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             "target_type": "revision",
         },
     }
 
     expected_snapshot = {
         "id": "0c5881c74283793ebe9a09a105a9381e41380383",
         "branches": expected_branches,
     }
 
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
 
 def test_eoferror(swh_config, requests_mock_datadir):
     """Load a truncated archive which is invalid to make the uncompress
     function raising the exception EOFError. We then check if a
     snapshot is created, meaning this error is well managed.
 
     """
     sources = (
         "https://nix-community.github.io/nixpkgs-swh/sources-EOFError.json"  # noqa
     )
     loader = NixGuixLoader(sources)
     loader.load()
 
     expected_branches = {
-        "evaluation": {
-            "target": "cc4e04c26672dd74e5fd0fecb78b435fb55368f7",
+        b"evaluation": {
+            "target": hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             "target_type": "revision",
         },
     }
     expected_snapshot = {
         "id": "4257fa2350168c6bfec726a06452ea27a2c0cb33",
         "branches": expected_branches,
     }
 
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
 
 def fake_download(
     url: str,
     dest: str,
     hashes: Dict = {},
     filename: Optional[str] = None,
     auth: Optional[Tuple[str, str]] = None,
 ) -> Tuple[str, Dict]:
     """Fake download which raises HashCollision (for the sake of test simpliciy,
     let's accept that makes sense)
 
     For tests purpose only.
 
     """
     if url == "https://example.com/file.txt":
         # instead of failing because it's a file not dealt with by the nix guix
         # loader, make it raise a hash collision
         raise HashCollision("sha1", "f92d74e3874587aaf443d1db961d4e26dde13e9c", [])
     return download(url, dest, hashes, filename, auth)
 
 
 def test_raise_exception(swh_config, requests_mock_datadir, mocker):
     mock_download = mocker.patch("swh.loader.package.loader.download")
     mock_download.side_effect = fake_download
 
     loader = NixGuixLoader(sources_url)
     res = loader.load()
 
     expected_snapshot_id = "0c5881c74283793ebe9a09a105a9381e41380383"
     assert res == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     expected_branches = {
-        "https://github.com/owner-1/repository-1/revision-1.tgz": {
-            "target": "488ad4e7b8e2511258725063cf43a2b897c503b4",
+        b"https://github.com/owner-1/repository-1/revision-1.tgz": {
+            "target": hash_to_bytes("488ad4e7b8e2511258725063cf43a2b897c503b4"),
             "target_type": "revision",
         },
-        "evaluation": {
-            "target": "cc4e04c26672dd74e5fd0fecb78b435fb55368f7",
+        b"evaluation": {
+            "target": hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             "target_type": "revision",
         },
     }
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
 
     snapshot = check_snapshot(expected_snapshot, storage=loader.storage)
     check_snapshot_revisions_ok(snapshot, loader.storage)
 
     assert len(mock_download.mock_calls) == 2
 
     # The visit is partial because some artifact downloads failed
     assert_last_visit_matches(
         loader.storage, sources_url, status="partial", type="nixguix"
     )
 
 
 def test_load_nixguix_one_common_artifact_from_other_loader(
     swh_config, datadir, requests_mock_datadir_visits, caplog
 ):
     """Misformatted revision should be caught and logged, then loading continues
 
     """
     caplog.set_level(logging.ERROR, "swh.loader.package.nixguix.loader")
 
     # 1. first ingest with for example the archive loader
     gnu_url = "https://ftp.gnu.org/gnu/8sync/"
     release = "0.1.0"
     artifact_url = f"https://ftp.gnu.org/gnu/8sync/8sync-{release}.tar.gz"
     gnu_artifacts = [
         {
             "time": 944729610,
             "url": artifact_url,
             "length": 221837,
             "filename": f"8sync-{release}.tar.gz",
             "version": release,
         }
     ]
     archive_loader = ArchiveLoader(url=gnu_url, artifacts=gnu_artifacts)
     actual_load_status = archive_loader.load()
     expected_snapshot_id = "c419397fd912039825ebdbea378bc6283f006bf5"
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] == expected_snapshot_id  # noqa
 
     assert_last_visit_matches(
         archive_loader.storage, gnu_url, status="full", type="tar"
     )
 
     gnu_snapshot = archive_loader.storage.snapshot_get(
         hash_to_bytes(expected_snapshot_id)
     )
 
     first_revision = gnu_snapshot["branches"][f"releases/{release}".encode("utf-8")]
 
     # 2. Then ingest with the nixguix loader which lists the same artifact within its
     # sources.json
 
     # ensure test setup is ok
     data_sources = os.path.join(
         datadir, "https_nix-community.github.io", "nixpkgs-swh_sources_special.json"
     )
     all_sources = json.loads(open(data_sources).read())
     found = False
     for source in all_sources["sources"]:
         if source["urls"][0] == artifact_url:
             found = True
             assert (
                 found is True
             ), f"test setup error: {artifact_url} must be in {data_sources}"
 
     # first visit with a snapshot, ok
     sources_url = "https://nix-community.github.io/nixpkgs-swh/sources_special.json"
     loader = NixGuixLoader(sources_url)
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "eventful"
 
     assert_last_visit_matches(
         loader.storage, sources_url, status="full", type="nixguix"
     )
 
     snapshot_id = actual_load_status2["snapshot_id"]
     snapshot = loader.storage.snapshot_get(hash_to_bytes(snapshot_id))
     snapshot.pop("next_branch")  # snapshot_get endpoint detail to drop
 
     # simulate a snapshot already seen with a revision with the wrong metadata structure
     # This revision should be skipped, thus making the artifact being ingested again.
     with patch(
         "swh.loader.package.loader.PackageLoader.last_snapshot"
     ) as last_snapshot:
         # mutate the snapshot to target a revision with the wrong metadata structure
         # snapshot["branches"][artifact_url.encode("utf-8")] = first_revision
         old_revision = next(loader.storage.revision_get([first_revision["target"]]))
         # assert that revision is not in the right format
         assert old_revision["metadata"]["extrinsic"]["raw"].get("integrity", {}) == {}
 
         # mutate snapshot to create a clash
         snapshot["branches"][artifact_url.encode("utf-8")] = {
             "target_type": "revision",
-            "target": old_revision["id"],
+            "target": hash_to_bytes(old_revision["id"]),
         }
 
         # modify snapshot to actually change revision metadata structure so we simulate
         # a revision written by somebody else (structure different)
         last_snapshot.return_value = Snapshot.from_dict(snapshot)
 
         loader = NixGuixLoader(sources_url)
         actual_load_status3 = loader.load()
         assert last_snapshot.called
         assert actual_load_status3["status"] == "eventful"
 
         assert_last_visit_matches(
             loader.storage, sources_url, status="full", type="nixguix"
         )
 
         new_snapshot_id = "32ff641e510aceefc3a6d0dcbf208b2854d2e965"
         assert actual_load_status3["snapshot_id"] == new_snapshot_id
 
         last_snapshot = loader.storage.snapshot_get(hash_to_bytes(new_snapshot_id))
         new_revision_branch = last_snapshot["branches"][artifact_url.encode("utf-8")]
         assert new_revision_branch["target_type"] == "revision"
 
         new_revision = next(
             loader.storage.revision_get([new_revision_branch["target"]])
         )
 
         # the new revision has the correct structure,  so it got ingested alright by the
         # new run
         assert new_revision["metadata"]["extrinsic"]["raw"]["integrity"] is not None
 
         nb_detections = 0
         actual_detection: Dict
         for record in caplog.records:
             logtext = record.getMessage()
             if "Unexpected metadata revision structure detected:" in logtext:
                 nb_detections += 1
                 actual_detection = record.args["context"]
 
         assert actual_detection
         # as many calls as there are sources listed in the sources.json
         assert nb_detections == len(all_sources["sources"])
 
         assert actual_detection == {
             "revision": hash_to_hex(old_revision["id"]),
             "reason": "'integrity'",
             "known_artifact": old_revision["metadata"],
         }
diff --git a/swh/loader/package/npm/tests/test_npm.py b/swh/loader/package/npm/tests/test_npm.py
index 67b4f6a..0cebac8 100644
--- a/swh/loader/package/npm/tests/test_npm.py
+++ b/swh/loader/package/npm/tests/test_npm.py
@@ -1,585 +1,585 @@
 # Copyright (C) 2019-2020  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 pytest
 
 from swh.model.hashutil import hash_to_bytes
 from swh.model.model import Person
 
 from swh.loader.package.npm.loader import (
     NpmLoader,
     extract_npm_package_author,
     artifact_to_revision_id,
 )
 from swh.loader.package.tests.common import check_metadata_paths
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 
 def test_extract_npm_package_author(datadir):
     package_metadata_filepath = os.path.join(
         datadir, "https_replicate.npmjs.com", "org_visit1"
     )
 
     with open(package_metadata_filepath) as json_file:
         package_metadata = json.load(json_file)
 
     extract_npm_package_author(package_metadata["versions"]["0.0.2"]) == Person(
         fullname=b"mooz <stillpedant@gmail.com>",
         name=b"mooz",
         email=b"stillpedant@gmail.com",
     )
 
     assert extract_npm_package_author(package_metadata["versions"]["0.0.3"]) == Person(
         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) == Person(
         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": [
             {
                 "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"
         }
     }"""
     )
 
     assert extract_npm_package_author(package_json) == Person(
         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) == Person(
         fullname=b"fengmk2 <fengmk2@gmail.com> (https://fengmk2.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) == Person(
         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"
         ),
     }
 )
 
 
 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_revision_metadata_structure(swh_config, requests_mock_datadir):
     package = "org"
     loader = NpmLoader(package_url(package))
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     expected_revision_id = hash_to_bytes("d8a1c7474d2956ac598a19f0f27d52f7015f117e")
     revision = list(loader.storage.revision_get([expected_revision_id]))[0]
 
     assert revision is not None
 
     check_metadata_paths(
         revision["metadata"],
         paths=[
             ("intrinsic.tool", str),
             ("intrinsic.raw", dict),
             ("extrinsic.provider", str),
             ("extrinsic.when", str),
             ("extrinsic.raw", dict),
             ("original_artifact", list),
         ],
     )
 
     for original_artifact in revision["metadata"]["original_artifact"]:
         check_metadata_paths(
             original_artifact,
             paths=[("filename", str), ("length", int), ("checksums", dict),],
         )
 
 
 def test_npm_loader_first_visit(swh_config, requests_mock_datadir):
 
     package = "org"
     loader = NpmLoader(package_url(package))
 
     actual_load_status = loader.load()
     expected_snapshot_id = "d0587e1195aed5a8800411a008f2f2d627f18e2d"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     stats = get_stats(loader.storage)
 
     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)) == []
     )
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": {
-            "HEAD": {"target": "releases/0.0.4", "target_type": "alias"},
-            "releases/0.0.2": {
-                "target": "d8a1c7474d2956ac598a19f0f27d52f7015f117e",
+            b"HEAD": {"target": b"releases/0.0.4", "target_type": "alias"},
+            b"releases/0.0.2": {
+                "target": hash_to_bytes("d8a1c7474d2956ac598a19f0f27d52f7015f117e"),
                 "target_type": "revision",
             },
-            "releases/0.0.3": {
-                "target": "5f9eb78af37ffd12949f235e86fac04898f9f72a",
+            b"releases/0.0.3": {
+                "target": hash_to_bytes("5f9eb78af37ffd12949f235e86fac04898f9f72a"),
                 "target_type": "revision",
             },
-            "releases/0.0.4": {
-                "target": "ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a",
+            b"releases/0.0.4": {
+                "target": hash_to_bytes("ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a"),
                 "target_type": "revision",
             },
         },
     }
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_npm_loader_incremental_visit(swh_config, requests_mock_datadir_visits):
     package = "org"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["status"] is not None
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
     stats = get_stats(loader.storage)
 
     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
 
     loader._info = None  # reset loader internal state
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "eventful"
     snap_id2 = actual_load_status2["snapshot_id"]
     assert snap_id2 is not None
     assert snap_id2 != actual_load_status["snapshot_id"]
 
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
     stats = get_stats(loader.storage)
 
     assert {  # 3 new releases artifacts
         "content": len(_expected_new_contents_first_visit) + 14,
         "directory": len(_expected_new_directories_first_visit) + 15,
         "origin": 1,
         "origin_visit": 2,
         "person": 2,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit) + 3,
         "skipped_content": 0,
         "snapshot": 2,
     } == stats
 
     urls = [
         m.url
         for m in requests_mock_datadir_visits.request_history
         if m.url.startswith("https://registry.npmjs.org")
     ]
     assert len(urls) == len(set(urls))  # we visited each artifact once across
 
 
 @pytest.mark.usefixtures("requests_mock_datadir")
 def test_npm_loader_version_divergence(swh_config):
     package = "@aller_shared"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["status"] is not None
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
     stats = get_stats(loader.storage)
 
     assert {  # 1 new releases artifacts
         "content": 534,
         "directory": 153,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_snapshot = {
         "id": "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92",
         "branches": {
-            "HEAD": {"target_type": "alias", "target": "releases/0.1.0"},
-            "releases/0.1.0": {
+            b"HEAD": {"target_type": "alias", "target": b"releases/0.1.0"},
+            b"releases/0.1.0": {
                 "target_type": "revision",
-                "target": "845673bfe8cbd31b1eaf757745a964137e6f9116",
+                "target": hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"),
             },
-            "releases/0.1.1-alpha.14": {
+            b"releases/0.1.1-alpha.14": {
                 "target_type": "revision",
-                "target": "05181c12cd8c22035dd31155656826b85745da37",
+                "target": hash_to_bytes("05181c12cd8c22035dd31155656826b85745da37"),
             },
         },
     }
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_npm_artifact_to_revision_id_none():
     """Current loader version should stop soon if nothing can be found
 
     """
     artifact_metadata = {
         "dist": {"shasum": "05181c12cd8c22035dd31155656826b85745da37",},
     }
 
     known_artifacts = {
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92": {},
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) is None
 
 
 def test_npm_artifact_to_revision_id_old_loader_version():
     """Current loader version should solve old metadata scheme
 
     """
     artifact_metadata = {
         "dist": {"shasum": "05181c12cd8c22035dd31155656826b85745da37",}
     }
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "package_source": {"sha1": "something-wrong"}
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "package_source": {"sha1": "05181c12cd8c22035dd31155656826b85745da37",}
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "845673bfe8cbd31b1eaf757745a964137e6f9116"
     )
 
 
 def test_npm_artifact_to_revision_id_current_loader_version():
     """Current loader version should be able to solve current metadata scheme
 
     """
     artifact_metadata = {
         "dist": {"shasum": "05181c12cd8c22035dd31155656826b85745da37",}
     }
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "original_artifact": [
                 {"checksums": {"sha1": "05181c12cd8c22035dd31155656826b85745da37"},}
             ],
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "original_artifact": [{"checksums": {"sha1": "something-wrong"},}],
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"
     )
 
 
 def test_npm_artifact_with_no_intrinsic_metadata(swh_config, requests_mock_datadir):
     """Skip artifact with no intrinsic metadata during ingestion
 
     """
     package = "nativescript-telerik-analytics"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
 
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = {
         "id": "1a8893e6a86f444e8be8e7bda6cb34fb1735a00e",
         "branches": {},
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
 
 def test_npm_artifact_with_no_upload_time(swh_config, requests_mock_datadir):
     """With no time upload, artifact is skipped
 
     """
     package = "jammit-no-time"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
 
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = {
         "id": "1a8893e6a86f444e8be8e7bda6cb34fb1735a00e",
         "branches": {},
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="npm")
 
 
 def test_npm_artifact_use_mtime_if_no_time(swh_config, requests_mock_datadir):
     """With no time upload, artifact is skipped
 
     """
     package = "jammit-express"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
 
     # artifact is used
     expected_snapshot = {
         "id": "d6e08e19159f77983242877c373c75222d5ae9dd",
         "branches": {
-            "HEAD": {"target_type": "alias", "target": "releases/0.0.1"},
-            "releases/0.0.1": {
+            b"HEAD": {"target_type": "alias", "target": b"releases/0.0.1"},
+            b"releases/0.0.1": {
                 "target_type": "revision",
-                "target": "9e4dd2b40d1b46b70917c0949aa2195c823a648e",
+                "target": hash_to_bytes("9e4dd2b40d1b46b70917c0949aa2195c823a648e"),
             },
         },
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
 
 def test_npm_no_artifact(swh_config, requests_mock_datadir):
     """If no artifacts at all is found for origin, the visit fails completely
 
     """
     package = "catify"
     url = package_url(package)
     loader = NpmLoader(url)
     actual_load_status = loader.load()
     assert actual_load_status == {
         "status": "failed",
     }
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="npm")
diff --git a/swh/loader/package/pypi/tests/test_pypi.py b/swh/loader/package/pypi/tests/test_pypi.py
index e9891e5..ba1a9ce 100644
--- a/swh/loader/package/pypi/tests/test_pypi.py
+++ b/swh/loader/package/pypi/tests/test_pypi.py
@@ -1,831 +1,831 @@
 # Copyright (C) 2019-2020 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 os import path
 
 import pytest
 
 from unittest.mock import patch
 
 from swh.core.tarball import uncompress
 from swh.core.pytest_plugin import requests_mock_datadir_factory
 from swh.model.hashutil import hash_to_bytes
 from swh.model.model import Person
 
 from swh.loader.package.pypi.loader import (
     PyPILoader,
     pypi_api_url,
     author,
     extract_intrinsic_metadata,
     artifact_to_revision_id,
 )
 from swh.loader.package.tests.common import check_metadata_paths
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 
 def test_author_basic():
     data = {
         "author": "i-am-groot",
         "author_email": "iam@groot.org",
     }
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"i-am-groot <iam@groot.org>",
         name=b"i-am-groot",
         email=b"iam@groot.org",
     )
 
     assert actual_author == expected_author
 
 
 def test_author_empty_email():
     data = {
         "author": "i-am-groot",
         "author_email": "",
     }
     actual_author = author(data)
 
     expected_author = Person(fullname=b"i-am-groot", name=b"i-am-groot", email=b"",)
 
     assert actual_author == expected_author
 
 
 def test_author_empty_name():
     data = {
         "author": "",
         "author_email": "iam@groot.org",
     }
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b" <iam@groot.org>", name=b"", email=b"iam@groot.org",
     )
 
     assert actual_author == expected_author
 
 
 def test_author_malformed():
     data = {
         "author": "['pierre', 'paul', 'jacques']",
         "author_email": None,
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"['pierre', 'paul', 'jacques']",
         name=b"['pierre', 'paul', 'jacques']",
         email=None,
     )
 
     assert actual_author == expected_author
 
 
 def test_author_malformed_2():
     data = {
         "author": "[marie, jeanne]",
         "author_email": "[marie@some, jeanne@thing]",
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=b"[marie, jeanne] <[marie@some, jeanne@thing]>",
         name=b"[marie, jeanne]",
         email=b"[marie@some, jeanne@thing]",
     )
 
     assert actual_author == expected_author
 
 
 def test_author_malformed_3():
     data = {
         "author": "[marie, jeanne, pierre]",
         "author_email": "[marie@somewhere.org, jeanne@somewhere.org]",
     }
 
     actual_author = author(data)
 
     expected_author = Person(
         fullname=(
             b"[marie, jeanne, pierre] " b"<[marie@somewhere.org, jeanne@somewhere.org]>"
         ),
         name=b"[marie, jeanne, pierre]",
         email=b"[marie@somewhere.org, jeanne@somewhere.org]",
     )
 
     actual_author == expected_author
 
 
 # configuration error #
 
 
 def test_badly_configured_loader_raise(monkeypatch):
     """Badly configured loader should raise"""
     monkeypatch.delenv("SWH_CONFIG_FILENAME", raising=False)
     with pytest.raises(ValueError) as e:
         PyPILoader(url="some-url")
 
     assert "Misconfiguration" in e.value.args[0]
 
 
 def test_pypi_api_url():
     """Compute pypi api url from the pypi project url should be ok"""
     url = pypi_api_url("https://pypi.org/project/requests")
     assert url == "https://pypi.org/pypi/requests/json"
 
 
 def test_pypi_api_url_with_slash():
     """Compute pypi api url from the pypi project url should be ok"""
     url = pypi_api_url("https://pypi.org/project/requests/")
     assert url == "https://pypi.org/pypi/requests/json"
 
 
 @pytest.mark.fs
 def test_extract_intrinsic_metadata(tmp_path, datadir):
     """Parsing existing archive's PKG-INFO should yield results"""
     uncompressed_archive_path = str(tmp_path)
     archive_path = path.join(
         datadir, "https_files.pythonhosted.org", "0805nexter-1.1.0.zip"
     )
     uncompress(archive_path, dest=uncompressed_archive_path)
 
     actual_metadata = extract_intrinsic_metadata(uncompressed_archive_path)
     expected_metadata = {
         "metadata_version": "1.0",
         "name": "0805nexter",
         "version": "1.1.0",
         "summary": "a simple printer of nested lest",
         "home_page": "http://www.hp.com",
         "author": "hgtkpython",
         "author_email": "2868989685@qq.com",
         "platforms": ["UNKNOWN"],
     }
 
     assert actual_metadata == expected_metadata
 
 
 @pytest.mark.fs
 def test_extract_intrinsic_metadata_failures(tmp_path):
     """Parsing inexistent path/archive/PKG-INFO yield None"""
     tmp_path = str(tmp_path)  # py3.5 work around (PosixPath issue)
     # inexistent first level path
     assert extract_intrinsic_metadata("/something-inexistent") == {}
     # inexistent second level path (as expected by pypi archives)
     assert extract_intrinsic_metadata(tmp_path) == {}
     # inexistent PKG-INFO within second level path
     existing_path_no_pkginfo = path.join(tmp_path, "something")
     os.mkdir(existing_path_no_pkginfo)
     assert extract_intrinsic_metadata(tmp_path) == {}
 
 
 # LOADER SCENARIO #
 
 # "edge" cases (for the same origin) #
 
 
 # no release artifact:
 # {visit full, status: uneventful, no contents, etc...}
 requests_mock_datadir_missing_all = requests_mock_datadir_factory(
     ignore_urls=[
         "https://files.pythonhosted.org/packages/ec/65/c0116953c9a3f47de89e71964d6c7b0c783b01f29fa3390584dbf3046b4d/0805nexter-1.1.0.zip",  # noqa
         "https://files.pythonhosted.org/packages/c4/a0/4562cda161dc4ecbbe9e2a11eb365400c0461845c5be70d73869786809c4/0805nexter-1.2.0.zip",  # noqa
     ]
 )
 
 
 def test_no_release_artifact(swh_config, requests_mock_datadir_missing_all):
     """Load a pypi project with all artifacts missing ends up with no snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "uneventful"
     assert actual_load_status["snapshot_id"] is not None
 
     stats = get_stats(loader.storage)
     assert {
         "content": 0,
         "directory": 0,
         "origin": 1,
         "origin_visit": 1,
         "person": 0,
         "release": 0,
         "revision": 0,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="pypi")
 
 
 # problem during loading:
 # {visit: partial, status: uneventful, no snapshot}
 
 
 def test_release_with_traceback(swh_config, requests_mock_datadir):
     url = "https://pypi.org/project/0805nexter"
     with patch(
         "swh.loader.package.pypi.loader.PyPILoader.last_snapshot",
         side_effect=ValueError("Fake problem to fail the visit"),
     ):
         loader = PyPILoader(url)
 
         actual_load_status = loader.load()
         assert actual_load_status == {"status": "failed"}
 
         stats = get_stats(loader.storage)
 
         assert {
             "content": 0,
             "directory": 0,
             "origin": 1,
             "origin_visit": 1,
             "person": 0,
             "release": 0,
             "revision": 0,
             "skipped_content": 0,
             "snapshot": 0,
         } == stats
 
         assert_last_visit_matches(loader.storage, url, status="partial", type="pypi")
 
 
 # problem during loading: failure early enough in between swh contents...
 # some contents (contents, directories, etc...) have been written in storage
 # {visit: partial, status: eventful, no snapshot}
 
 # problem during loading: failure late enough we can have snapshots (some
 # revisions are written in storage already)
 # {visit: partial, status: eventful, snapshot}
 
 # "normal" cases (for the same origin) #
 
 
 requests_mock_datadir_missing_one = requests_mock_datadir_factory(
     ignore_urls=[
         "https://files.pythonhosted.org/packages/ec/65/c0116953c9a3f47de89e71964d6c7b0c783b01f29fa3390584dbf3046b4d/0805nexter-1.1.0.zip",  # noqa
     ]
 )
 
 # some missing release artifacts:
 # {visit partial, status: eventful, 1 snapshot}
 
 
 def test_revision_metadata_structure(swh_config, requests_mock_datadir):
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     expected_revision_id = hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21")
     revision = list(loader.storage.revision_get([expected_revision_id]))[0]
 
     assert revision is not None
 
     check_metadata_paths(
         revision["metadata"],
         paths=[
             ("intrinsic.tool", str),
             ("intrinsic.raw", dict),
             ("extrinsic.provider", str),
             ("extrinsic.when", str),
             ("extrinsic.raw", dict),
             ("original_artifact", list),
         ],
     )
 
     for original_artifact in revision["metadata"]["original_artifact"]:
         check_metadata_paths(
             original_artifact,
             paths=[("filename", str), ("length", int), ("checksums", dict),],
         )
 
 
 def test_visit_with_missing_artifact(swh_config, requests_mock_datadir_missing_one):
     """Load a pypi project with some missing artifacts ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "dd0e4201a232b1c104433741dbf45895b8ac9355"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     stats = get_stats(loader.storage)
 
     assert {
         "content": 3,
         "directory": 2,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 1,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
         ],
     )
 
     assert list(loader.storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
         ],
     )
 
     assert list(loader.storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
     }
     assert list(loader.storage.revision_missing(expected_revs)) == []
 
     expected_branches = {
-        "releases/1.2.0": {
-            "target": "e445da4da22b31bfebb6ffc4383dbf839a074d21",
+        b"releases/1.2.0": {
+            "target": hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
             "target_type": "revision",
         },
-        "HEAD": {"target": "releases/1.2.0", "target_type": "alias",},
+        b"HEAD": {"target": b"releases/1.2.0", "target_type": "alias",},
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     check_snapshot(expected_snapshot, storage=loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="pypi")
 
 
 def test_visit_with_1_release_artifact(swh_config, requests_mock_datadir):
     """With no prior visit, load a pypi project ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     stats = get_stats(loader.storage)
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "a61e24cdfdab3bb7817f6be85d37a3e666b34566",
             "938c33483285fd8ad57f15497f538320df82aeb8",
             "a27576d60e08c94a05006d2e6d540c0fdb5f38c8",
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
         ],
     )
 
     assert list(loader.storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d",
             "cf019eb456cf6f78d8c4674596f1c9a97ece8f44",
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
         ],
     )
 
     assert list(loader.storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"): hash_to_bytes(
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d"
         ),  # noqa
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
     }
     assert list(loader.storage.revision_missing(expected_revs)) == []
 
     expected_branches = {
-        "releases/1.1.0": {
-            "target": "4c99891f93b81450385777235a37b5e966dd1571",
+        b"releases/1.1.0": {
+            "target": hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
             "target_type": "revision",
         },
-        "releases/1.2.0": {
-            "target": "e445da4da22b31bfebb6ffc4383dbf839a074d21",
+        b"releases/1.2.0": {
+            "target": hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
             "target_type": "revision",
         },
-        "HEAD": {"target": "releases/1.2.0", "target_type": "alias",},
+        b"HEAD": {"target": b"releases/1.2.0", "target_type": "alias",},
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
 
 def test_multiple_visits_with_no_change(swh_config, requests_mock_datadir):
     """Multiple visits with no changes results in 1 same snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     snapshot_id = "ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": snapshot_id,
     }
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
     stats = get_stats(loader.storage)
 
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_branches = {
-        "releases/1.1.0": {
-            "target": "4c99891f93b81450385777235a37b5e966dd1571",
+        b"releases/1.1.0": {
+            "target": hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
             "target_type": "revision",
         },
-        "releases/1.2.0": {
-            "target": "e445da4da22b31bfebb6ffc4383dbf839a074d21",
+        b"releases/1.2.0": {
+            "target": hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
             "target_type": "revision",
         },
-        "HEAD": {"target": "releases/1.2.0", "target_type": "alias",},
+        b"HEAD": {"target": b"releases/1.2.0", "target_type": "alias",},
     }
 
     expected_snapshot = {
         "id": snapshot_id,
         "branches": expected_branches,
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     actual_load_status2 = loader.load()
     assert actual_load_status2 == {
         "status": "uneventful",
         "snapshot_id": actual_load_status2["snapshot_id"],
     }
 
     visit_status2 = assert_last_visit_matches(
         loader.storage, url, status="full", type="pypi"
     )
 
     stats2 = get_stats(loader.storage)
     expected_stats2 = stats.copy()
     expected_stats2["origin_visit"] = 1 + 1
     assert expected_stats2 == stats2
 
     # same snapshot
     actual_snapshot_id = visit_status2.snapshot
     assert actual_snapshot_id == hash_to_bytes(snapshot_id)
 
 
 def test_incremental_visit(swh_config, requests_mock_datadir_visits):
     """With prior visit, 2nd load will result with a different snapshot
 
     """
     url = "https://pypi.org/project/0805nexter"
     loader = PyPILoader(url)
 
     visit1_actual_load_status = loader.load()
     visit1_stats = get_stats(loader.storage)
     expected_snapshot_id = "ba6e158ada75d0b3cfb209ffdf6daa4ed34a227a"
     assert visit1_actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
     assert {
         "content": 6,
         "directory": 4,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == visit1_stats
 
     # Reset internal state
     loader._info = None
 
     visit2_actual_load_status = loader.load()
     visit2_stats = get_stats(loader.storage)
 
     assert visit2_actual_load_status["status"] == "eventful"
     expected_snapshot_id2 = "2e5149a7b0725d18231a37b342e9b7c4e121f283"
     assert visit2_actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id2,
     }
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
     assert {
         "content": 6 + 1,  # 1 more content
         "directory": 4 + 2,  # 2 more directories
         "origin": 1,
         "origin_visit": 1 + 1,
         "person": 1,
         "release": 0,
         "revision": 2 + 1,  # 1 more revision
         "skipped_content": 0,
         "snapshot": 1 + 1,  # 1 more snapshot
     } == visit2_stats
 
     expected_contents = map(
         hash_to_bytes,
         [
             "a61e24cdfdab3bb7817f6be85d37a3e666b34566",
             "938c33483285fd8ad57f15497f538320df82aeb8",
             "a27576d60e08c94a05006d2e6d540c0fdb5f38c8",
             "405859113963cb7a797642b45f171d6360425d16",
             "e5686aa568fdb1d19d7f1329267082fe40482d31",
             "83ecf6ec1114fd260ca7a833a2d165e71258c338",
             "92689fa2b7fb4d4fc6fb195bf73a50c87c030639",
         ],
     )
 
     assert list(loader.storage.content_missing_per_sha1(expected_contents)) == []
 
     expected_dirs = map(
         hash_to_bytes,
         [
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d",
             "cf019eb456cf6f78d8c4674596f1c9a97ece8f44",
             "b178b66bd22383d5f16f4f5c923d39ca798861b4",
             "c3a58f8b57433a4b56caaa5033ae2e0931405338",
             "e226e7e4ad03b4fc1403d69a18ebdd6f2edd2b3a",
             "52604d46843b898f5a43208045d09fcf8731631b",
         ],
     )
 
     assert list(loader.storage.directory_missing(expected_dirs)) == []
 
     # {revision hash: directory hash}
     expected_revs = {
         hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"): hash_to_bytes(
             "05219ba38bc542d4345d5638af1ed56c7d43ca7d"
         ),  # noqa
         hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"): hash_to_bytes(
             "b178b66bd22383d5f16f4f5c923d39ca798861b4"
         ),  # noqa
         hash_to_bytes("51247143b01445c9348afa9edfae31bf7c5d86b1"): hash_to_bytes(
             "e226e7e4ad03b4fc1403d69a18ebdd6f2edd2b3a"
         ),  # noqa
     }
 
     assert list(loader.storage.revision_missing(expected_revs)) == []
 
     expected_branches = {
-        "releases/1.1.0": {
-            "target": "4c99891f93b81450385777235a37b5e966dd1571",
+        b"releases/1.1.0": {
+            "target": hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
             "target_type": "revision",
         },
-        "releases/1.2.0": {
-            "target": "e445da4da22b31bfebb6ffc4383dbf839a074d21",
+        b"releases/1.2.0": {
+            "target": hash_to_bytes("e445da4da22b31bfebb6ffc4383dbf839a074d21"),
             "target_type": "revision",
         },
-        "releases/1.3.0": {
-            "target": "51247143b01445c9348afa9edfae31bf7c5d86b1",
+        b"releases/1.3.0": {
+            "target": hash_to_bytes("51247143b01445c9348afa9edfae31bf7c5d86b1"),
             "target_type": "revision",
         },
-        "HEAD": {"target": "releases/1.3.0", "target_type": "alias",},
+        b"HEAD": {"target": b"releases/1.3.0", "target_type": "alias",},
     }
     expected_snapshot = {
         "id": expected_snapshot_id2,
         "branches": expected_branches,
     }
 
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
     urls = [
         m.url
         for m in requests_mock_datadir_visits.request_history
         if m.url.startswith("https://files.pythonhosted.org")
     ]
     # visited each artifact once across 2 visits
     assert len(urls) == len(set(urls))
 
 
 # release artifact, no new artifact
 # {visit full, status uneventful, same snapshot as before}
 
 # release artifact, old artifact with different checksums
 # {visit full, status full, new snapshot with shared history and some new
 # different history}
 
 # release with multiple sdist artifacts per pypi "version"
 # snapshot branch output is different
 
 
 def test_visit_1_release_with_2_artifacts(swh_config, requests_mock_datadir):
     """With no prior visit, load a pypi project ends up with 1 snapshot
 
     """
     url = "https://pypi.org/project/nexter"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "a27e638a4dad6fbfa273c6ebec1c4bf320fb84c6"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     expected_branches = {
-        "releases/1.1.0/nexter-1.1.0.zip": {
-            "target": "4c99891f93b81450385777235a37b5e966dd1571",
+        b"releases/1.1.0/nexter-1.1.0.zip": {
+            "target": hash_to_bytes("4c99891f93b81450385777235a37b5e966dd1571"),
             "target_type": "revision",
         },
-        "releases/1.1.0/nexter-1.1.0.tar.gz": {
-            "target": "0bf88f5760cca7665d0af4d6575d9301134fe11a",
+        b"releases/1.1.0/nexter-1.1.0.tar.gz": {
+            "target": hash_to_bytes("0bf88f5760cca7665d0af4d6575d9301134fe11a"),
             "target_type": "revision",
         },
     }
 
     expected_snapshot = {
         "id": expected_snapshot_id,
         "branches": expected_branches,
     }
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
 
 
 def test_pypi_artifact_to_revision_id_none():
     """Current loader version should stop soon if nothing can be found
 
     """
     artifact_metadata = {
         "digests": {
             "sha256": "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec",  # noqa
         },
     }
 
     assert artifact_to_revision_id({}, artifact_metadata) is None
 
     known_artifacts = {
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92": {
             "original_artifact": {"sha256": "something-irrelevant",},
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) is None
 
 
 def test_pypi_artifact_to_revision_id_old_loader_version():
     """Current loader version should solve old metadata scheme
 
     """
     artifact_metadata = {
         "digests": {
             "sha256": "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec",  # noqa
         }
     }
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "original_artifact": {"sha256": "something-wrong",},
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "original_artifact": {
                 "sha256": "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec",  # noqa
             },
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "845673bfe8cbd31b1eaf757745a964137e6f9116"
     )
 
 
 def test_pypi_artifact_to_revision_id_current_loader_version():
     """Current loader version should be able to solve current metadata scheme
 
     """
     artifact_metadata = {
         "digests": {
             "sha256": "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec",  # noqa
         }
     }
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "original_artifact": [
                 {
                     "checksums": {
                         "sha256": "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec",  # noqa
                     },
                 }
             ],
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "original_artifact": [{"checksums": {"sha256": "something-wrong"},}],
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"
     )
 
 
 def test_pypi_artifact_to_revision_id_failures():
     with pytest.raises(KeyError, match="sha256"):
         artifact_metadata = {
             "digests": {},
         }
         assert artifact_to_revision_id({}, artifact_metadata)
 
     with pytest.raises(KeyError, match="digests"):
         artifact_metadata = {
             "something": "wrong",
         }
         assert artifact_to_revision_id({}, artifact_metadata)
 
 
 def test_pypi_artifact_with_no_intrinsic_metadata(swh_config, requests_mock_datadir):
     """Skip artifact with no intrinsic metadata during ingestion
 
     """
     url = "https://pypi.org/project/upymenu"
     loader = PyPILoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = "1a8893e6a86f444e8be8e7bda6cb34fb1735a00e"
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id,
     }
 
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = {"id": expected_snapshot_id, "branches": {}}
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(loader.storage, url, status="full", type="pypi")
diff --git a/swh/loader/tests/test_init.py b/swh/loader/tests/test_init.py
index caafdab..4593a3e 100644
--- a/swh/loader/tests/test_init.py
+++ b/swh/loader/tests/test_init.py
@@ -1,455 +1,458 @@
 # Copyright (C) 2020  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 datetime
 import pytest
 
 import os
 import subprocess
 
 from swh.model.from_disk import DentryPerms
 from swh.model.model import (
     Content,
     Directory,
     DirectoryEntry,
     ObjectType,
     OriginVisit,
     OriginVisitStatus,
     Person,
     Release,
     Revision,
     RevisionType,
     Snapshot,
     SnapshotBranch,
     TargetType,
     Timestamp,
     TimestampWithTimezone,
 )
 from swh.model.hashutil import hash_to_bytes
 
 from swh.loader.tests import (
     assert_last_visit_matches,
     encode_target,
     check_snapshot,
     prepare_repository_from_archive,
     InconsistentAliasBranchError,
     InexistentObjectsError,
 )
 
 
 hash_hex = "43e45d56f88993aae6a0198013efa80716fd8920"
 
 
 ORIGIN_VISIT = OriginVisit(
     origin="some-url",
     visit=1,
     date=datetime.datetime.now(tz=datetime.timezone.utc),
     type="archive",
 )
 
 
 ORIGIN_VISIT_STATUS = OriginVisitStatus(
     origin="some-url",
     visit=1,
     date=datetime.datetime.now(tz=datetime.timezone.utc),
     status="full",
     snapshot=hash_to_bytes("d81cc0710eb6cf9efd5b920a8453e1e07157b6cd"),
     metadata=None,
 )
 
 
 CONTENT = Content(
     data=b"42\n",
     length=3,
     sha1=hash_to_bytes("34973274ccef6ab4dfaaf86599792fa9c3fe4689"),
     sha1_git=hash_to_bytes("d81cc0710eb6cf9efd5b920a8453e1e07157b6cd"),
     sha256=hash_to_bytes(
         "673650f936cb3b0a2f93ce09d81be10748b1b203c19e8176b4eefc1964a0cf3a"
     ),
     blake2s256=hash_to_bytes(
         "d5fe1939576527e42cfd76a9455a2432fe7f56669564577dd93c4280e76d661d"
     ),
     status="visible",
 )
 
 
 DIRECTORY = Directory(
     id=hash_to_bytes("34f335a750111ca0a8b64d8034faec9eedc396be"),
     entries=tuple(
         [
             DirectoryEntry(
                 name=b"foo",
                 type="file",
                 target=CONTENT.sha1_git,
                 perms=DentryPerms.content,
             )
         ]
     ),
 )
 
 
 REVISION = Revision(
     id=hash_to_bytes("066b1b62dbfa033362092af468bf6cfabec230e7"),
     message=b"hello",
     author=Person(
         name=b"Nicolas Dandrimont",
         email=b"nicolas@example.com",
         fullname=b"Nicolas Dandrimont <nicolas@example.com> ",
     ),
     date=TimestampWithTimezone(
         timestamp=Timestamp(seconds=1234567890, microseconds=0),
         offset=120,
         negative_utc=False,
     ),
     committer=Person(
         name=b"St\xc3fano Zacchiroli",
         email=b"stefano@example.com",
         fullname=b"St\xc3fano Zacchiroli <stefano@example.com>",
     ),
     committer_date=TimestampWithTimezone(
         timestamp=Timestamp(seconds=1123456789, microseconds=0),
         offset=0,
         negative_utc=True,
     ),
     parents=(),
     type=RevisionType.GIT,
     directory=DIRECTORY.id,
     metadata={
         "checksums": {"sha1": "tarball-sha1", "sha256": "tarball-sha256",},
         "signed-off-by": "some-dude",
     },
     extra_headers=(
         (b"gpgsig", b"test123"),
         (b"mergetag", b"foo\\bar"),
         (b"mergetag", b"\x22\xaf\x89\x80\x01\x00"),
     ),
     synthetic=True,
 )
 
 
 RELEASE = Release(
     id=hash_to_bytes("3e9050196aa288264f2a9d279d6abab8b158448b"),
     name=b"v0.0.2",
     author=Person(
         name=b"tony", email=b"tony@ardumont.fr", fullname=b"tony <tony@ardumont.fr>",
     ),
     date=TimestampWithTimezone(
         timestamp=Timestamp(seconds=1634336813, microseconds=0),
         offset=0,
         negative_utc=False,
     ),
     target=REVISION.id,
     target_type=ObjectType.REVISION,
     message=b"yet another synthetic release",
     synthetic=True,
 )
 
 
 SNAPSHOT = Snapshot(
     id=hash_to_bytes("2498dbf535f882bc7f9a18fb16c9ad27fda7bab7"),
     branches={
         b"release/0.1.0": SnapshotBranch(
             target=RELEASE.id, target_type=TargetType.RELEASE,
         ),
         b"HEAD": SnapshotBranch(target=REVISION.id, target_type=TargetType.REVISION,),
         b"alias": SnapshotBranch(target=b"HEAD", target_type=TargetType.ALIAS,),
         b"evaluation": SnapshotBranch(  # branch dedicated to not exist in storage
             target=hash_to_bytes("cc4e04c26672dd74e5fd0fecb78b435fb55368f7"),
             target_type=TargetType.REVISION,
         ),
     },
 )
 
 
 @pytest.fixture
 def mock_storage(mocker):
     mock_storage = mocker.patch("swh.loader.tests.origin_get_latest_visit_status")
     mock_storage.return_value = ORIGIN_VISIT, ORIGIN_VISIT_STATUS
     return mock_storage
 
 
 def test_assert_last_visit_matches_raise(mock_storage, mocker):
     """Not finding origin visit_and_statu should raise
 
     """
     # overwrite so we raise because we do not find the right visit
     mock_storage.return_value = None
 
     with pytest.raises(AssertionError, match="Origin url has no visits"):
         assert_last_visit_matches(mock_storage, "url", status="full")
 
     assert mock_storage.called is True
 
 
 def test_assert_last_visit_matches_wrong_status(mock_storage, mocker):
     """Wrong visit detected should raise AssertionError
 
     """
     expected_status = "partial"
     assert ORIGIN_VISIT_STATUS.status != expected_status
     with pytest.raises(AssertionError, match="Visit_status has status"):
         assert_last_visit_matches(mock_storage, "url", status=expected_status)
 
     assert mock_storage.called is True
 
 
 def test_assert_last_visit_matches_wrong_type(mock_storage, mocker):
     """Wrong visit detected should raise AssertionError
 
     """
     expected_type = "git"
     assert ORIGIN_VISIT.type != expected_type
     with pytest.raises(AssertionError, match="Visit has type"):
         assert_last_visit_matches(
             mock_storage,
             "url",
             status=ORIGIN_VISIT_STATUS.status,
             type=expected_type,  # mismatched type will raise
         )
 
     assert mock_storage.called is True
 
 
 def test_assert_last_visit_matches_wrong_snapshot(mock_storage, mocker):
     """Wrong visit detected should raise AssertionError
 
     """
     expected_snapshot_id = hash_to_bytes("e92cc0710eb6cf9efd5b920a8453e1e07157b6cd")
     assert ORIGIN_VISIT_STATUS.snapshot != expected_snapshot_id
 
     with pytest.raises(AssertionError, match="Visit_status points to snapshot"):
         assert_last_visit_matches(
             mock_storage,
             "url",
             status=ORIGIN_VISIT_STATUS.status,
             snapshot=expected_snapshot_id,  # mismatched snapshot will raise
         )
 
     assert mock_storage.called is True
 
 
 def test_assert_last_visit_matches(mock_storage, mocker):
     """Correct visit detected should return the visit_status
 
     """
     visit_type = ORIGIN_VISIT.type
     visit_status = ORIGIN_VISIT_STATUS.status
     visit_snapshot = ORIGIN_VISIT_STATUS.snapshot
 
     actual_visit_status = assert_last_visit_matches(
         mock_storage,
         "url",
         type=visit_type,
         status=visit_status,
         snapshot=visit_snapshot,
     )
 
     assert actual_visit_status == ORIGIN_VISIT_STATUS
     assert mock_storage.called is True
 
 
 def test_prepare_repository_from_archive_failure():
     # does not deal with inexistent archive so raise
     assert os.path.exists("unknown-archive") is False
     with pytest.raises(subprocess.CalledProcessError, match="exit status 2"):
         prepare_repository_from_archive("unknown-archive")
 
 
 def test_prepare_repository_from_archive(datadir, tmp_path):
     archive_name = "0805nexter-1.1.0"
     archive_path = os.path.join(str(datadir), f"{archive_name}.tar.gz")
     assert os.path.exists(archive_path) is True
 
     tmp_path = str(tmp_path)  # deals with path string
     repo_url = prepare_repository_from_archive(
         archive_path, filename=archive_name, tmp_path=tmp_path
     )
     expected_uncompressed_archive_path = os.path.join(tmp_path, archive_name)
     assert repo_url == f"file://{expected_uncompressed_archive_path}"
     assert os.path.exists(expected_uncompressed_archive_path)
 
 
 def test_prepare_repository_from_archive_no_filename(datadir, tmp_path):
     archive_name = "0805nexter-1.1.0"
     archive_path = os.path.join(str(datadir), f"{archive_name}.tar.gz")
     assert os.path.exists(archive_path) is True
 
     # deals with path as posix path (for tmp_path)
     repo_url = prepare_repository_from_archive(archive_path, tmp_path=tmp_path)
 
     tmp_path = str(tmp_path)
     expected_uncompressed_archive_path = os.path.join(tmp_path, archive_name)
     expected_repo_url = os.path.join(tmp_path, f"{archive_name}.tar.gz")
     assert repo_url == f"file://{expected_repo_url}"
 
     # passing along the filename does not influence the on-disk extraction
     # just the repo-url computation
     assert os.path.exists(expected_uncompressed_archive_path)
 
 
 def test_encode_target():
     assert encode_target(None) is None
 
     for target_alias in ["something", b"something"]:
         target = {
             "target_type": "alias",
             "target": target_alias,
         }
         actual_alias_encode_target = encode_target(target)
         assert actual_alias_encode_target == {
             "target_type": "alias",
             "target": b"something",
         }
 
     for hash_ in [hash_hex, hash_to_bytes(hash_hex)]:
         target = {"target_type": "revision", "target": hash_}
         actual_encode_target = encode_target(target)
         assert actual_encode_target == {
             "target_type": "revision",
             "target": hash_to_bytes(hash_hex),
         }
 
 
 def test_check_snapshot(swh_storage):
     """Everything should be fine when snapshot is found and the snapshot reference up to the
     revision exist in the storage.
 
     """
     # Create a consistent snapshot arborescence tree in storage
     found = False
     for entry in DIRECTORY.entries:
         if entry.target == CONTENT.sha1_git:
             found = True
             break
     assert found is True
 
     assert REVISION.directory == DIRECTORY.id
     assert RELEASE.target == REVISION.id
 
     for branch, target in SNAPSHOT.branches.items():
         if branch == b"alias":
             assert target.target in SNAPSHOT.branches
         elif branch == b"evaluation":
             # this one does not exist and we are safelisting its check below
             continue
         else:
             assert target.target in [REVISION.id, RELEASE.id]
 
     swh_storage.content_add([CONTENT.to_dict()])
     swh_storage.directory_add([DIRECTORY.to_dict()])
     swh_storage.revision_add([REVISION.to_dict()])
     swh_storage.release_add([RELEASE.to_dict()])
     s = swh_storage.snapshot_add([SNAPSHOT.to_dict()])
     assert s == {
         "snapshot:add": 1,
     }
 
     for snap in [SNAPSHOT, SNAPSHOT.to_dict()]:
         # all should be fine!
         check_snapshot(
             snap, swh_storage, allowed_empty=[(TargetType.REVISION, b"evaluation")]
         )
 
 
 def test_check_snapshot_failures(swh_storage):
     """Failure scenarios:
 
     0. snapshot parameter is not a snapshot
     1. snapshot id is correct but branches mismatched
     2. snapshot id is not correct, it's not found in the storage
     3. snapshot reference an alias which does not exist
     4. snapshot is found in storage, targeted revision does not exist
     5. snapshot is found in storage, targeted release does not exist
 
     The following are not dealt with yet:
     6. snapshot is found in storage, targeted directory does not exist
     7. snapshot is found in storage, targeted content does not exist
 
     """
     snap_id_hex = "2498dbf535f882bc7f9a18fb16c9ad27fda7bab7"
     snapshot = Snapshot(
         id=hash_to_bytes(snap_id_hex),
         branches={
             b"master": SnapshotBranch(
                 target=hash_to_bytes(hash_hex), target_type=TargetType.REVISION,
             ),
         },
     )
 
     s = swh_storage.snapshot_add([snapshot])
     assert s == {
         "snapshot:add": 1,
     }
 
     unexpected_snapshot = {
         "id": "2498dbf535f882bc7f9a18fb16c9ad27fda7bab7",  # id is correct
         "branches": {
-            "master": {"target": hash_hex, "target_type": "release",}  # wrong branch
+            b"master": {
+                "target": hash_to_bytes(hash_hex),  # wrong branch
+                "target_type": "release",
+            }
         },
     }
 
     # 0. not a Snapshot object, raise!
     with pytest.raises(AssertionError, match="variable 'snapshot' must be a snapshot"):
         check_snapshot(ORIGIN_VISIT, swh_storage)
 
     # 1. snapshot id is correct but branches mismatched
     for snap_id in [snap_id_hex, snapshot.id]:
         with pytest.raises(AssertionError, match="Differing attributes"):
             unexpected_snapshot["id"] = snap_id
             check_snapshot(unexpected_snapshot, swh_storage)
 
     # 2. snapshot id is not correct, it's not found in the storage
     wrong_snap_id_hex = "999666f535f882bc7f9a18fb16c9ad27fda7bab7"
     for snap_id in [wrong_snap_id_hex, hash_to_bytes(wrong_snap_id_hex)]:
         unexpected_snapshot["id"] = wrong_snap_id_hex
         with pytest.raises(AssertionError, match="is not found"):
             check_snapshot(unexpected_snapshot, swh_storage)
 
     # 3. snapshot references an inexistent alias
     snapshot0 = Snapshot(
         id=hash_to_bytes("123666f535f882bc7f9a18fb16c9ad27fda7bab7"),
         branches={
             b"alias": SnapshotBranch(target=b"HEAD", target_type=TargetType.ALIAS,),
         },
     )
     swh_storage.snapshot_add([snapshot0])
 
     with pytest.raises(InconsistentAliasBranchError, match="Alias branch HEAD"):
         check_snapshot(snapshot0, swh_storage)
 
     # 4. snapshot is found in storage, targeted revision does not exist
     snapshot1 = Snapshot(
         id=hash_to_bytes("456666f535f882bc7f9a18fb16c9ad27fda7bab7"),
         branches={
             b"alias": SnapshotBranch(target=b"HEAD", target_type=TargetType.ALIAS,),
             b"HEAD": SnapshotBranch(
                 target=REVISION.id, target_type=TargetType.REVISION,
             ),
         },
     )
 
     swh_storage.snapshot_add([snapshot1])
 
     with pytest.raises(InexistentObjectsError, match="Branch/Revision"):
         check_snapshot(snapshot1, swh_storage)
 
     swh_storage.revision_add([REVISION.to_dict()])
     snapshot2 = Snapshot(
         id=hash_to_bytes("789666f535f882bc7f9a18fb16c9ad27fda7bab7"),
         branches={
             b"alias": SnapshotBranch(target=b"HEAD", target_type=TargetType.ALIAS,),
             b"HEAD": SnapshotBranch(
                 target=REVISION.id, target_type=TargetType.REVISION,
             ),
             b"release/0.1.0": SnapshotBranch(
                 target=RELEASE.id, target_type=TargetType.RELEASE,
             ),
         },
     )
 
     swh_storage.snapshot_add([snapshot2])
 
     with pytest.raises(InexistentObjectsError, match="Branch/Release"):
         check_snapshot(snapshot2, swh_storage)