diff --git a/swh/journal/tests/journal_data.py b/swh/journal/tests/journal_data.py
index 9e8b242..c20a2fe 100644
--- a/swh/journal/tests/journal_data.py
+++ b/swh/journal/tests/journal_data.py
@@ -1,176 +1,177 @@
 # 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 datetime
 
 from typing import Any, Dict, List, Type
 
 from swh.model.hashutil import MultiHash, hash_to_bytes
 from swh.journal.serializers import ModelObject
 
 from swh.model.model import (
     BaseModel,
     Content,
     Directory,
     Origin,
     OriginVisit,
     Release,
     Revision,
     SkippedContent,
     Snapshot,
 )
 
 
 OBJECT_TYPES: Dict[Type[BaseModel], str] = {
     Content: "content",
     Directory: "directory",
     Origin: "origin",
     OriginVisit: "origin_visit",
     Release: "release",
     Revision: "revision",
     SkippedContent: "skipped_content",
     Snapshot: "snapshot",
 }
 
+UTC = datetime.timezone.utc
 
 CONTENTS = [
     {**MultiHash.from_data(b"foo").digest(), "length": 3, "status": "visible",},
 ]
 
 duplicate_content1 = {
     "length": 4,
     "sha1": hash_to_bytes("44973274ccef6ab4dfaaf86599792fa9c3fe4689"),
     "sha1_git": b"another-foo",
     "blake2s256": b"another-bar",
     "sha256": b"another-baz",
     "status": "visible",
 }
 
 # Craft a sha1 collision
 duplicate_content2 = duplicate_content1.copy()
 sha1_array = bytearray(duplicate_content1["sha1_git"])
 sha1_array[0] += 1
 duplicate_content2["sha1_git"] = bytes(sha1_array)
 
 
 DUPLICATE_CONTENTS = [duplicate_content1, duplicate_content2]
 
 
 COMMITTERS = [
     {"fullname": b"foo", "name": b"foo", "email": b"",},
     {"fullname": b"bar", "name": b"bar", "email": b"",},
 ]
 
 DATES = [
     {
         "timestamp": {"seconds": 1234567891, "microseconds": 0,},
         "offset": 120,
         "negative_utc": False,
     },
     {
         "timestamp": {"seconds": 1234567892, "microseconds": 0,},
         "offset": 120,
         "negative_utc": False,
     },
 ]
 
 REVISIONS = [
     {
         "id": hash_to_bytes("7026b7c1a2af56521e951c01ed20f255fa054238"),
         "message": b"hello",
         "date": DATES[0],
         "committer": COMMITTERS[0],
         "author": COMMITTERS[0],
         "committer_date": DATES[0],
         "type": "git",
         "directory": b"\x01" * 20,
         "synthetic": False,
         "metadata": None,
         "parents": [],
     },
     {
         "id": hash_to_bytes("368a48fe15b7db2383775f97c6b247011b3f14f4"),
         "message": b"hello again",
         "date": DATES[1],
         "committer": COMMITTERS[1],
         "author": COMMITTERS[1],
         "committer_date": DATES[1],
         "type": "hg",
         "directory": b"\x02" * 20,
         "synthetic": False,
         "metadata": None,
         "parents": [],
     },
 ]
 
 RELEASES = [
     {
         "id": hash_to_bytes("d81cc0710eb6cf9efd5b920a8453e1e07157b6cd"),
         "name": b"v0.0.1",
         "date": {
             "timestamp": {"seconds": 1234567890, "microseconds": 0,},
             "offset": 120,
             "negative_utc": False,
         },
         "author": COMMITTERS[0],
         "target_type": "revision",
         "target": b"\x04" * 20,
         "message": b"foo",
         "synthetic": False,
     },
 ]
 
 ORIGINS = [
     {"url": "https://somewhere.org/den/fox",},
     {"url": "https://overtherainbow.org/fox/den",},
 ]
 
 ORIGIN_VISITS = [
     {
         "origin": ORIGINS[0]["url"],
         "date": "2013-05-07 04:20:39.369271+00:00",
         "snapshot": None,  # TODO
         "status": "ongoing",  # TODO
         "metadata": {"foo": "bar"},
         "type": "git",
     },
     {
         "origin": ORIGINS[0]["url"],
         "date": "2018-11-27 17:20:39+00:00",
         "snapshot": None,  # TODO
         "status": "ongoing",  # TODO
         "metadata": {"baz": "qux"},
         "type": "git",
     },
 ]
 
 TEST_OBJECT_DICTS: Dict[str, List[Dict[str, Any]]] = {
     "content": CONTENTS,
     "directory": [],
     "origin": ORIGINS,
     "origin_visit": ORIGIN_VISITS,
     "release": RELEASES,
     "revision": REVISIONS,
     "snapshot": [],
     "skipped_content": [],
 }
 
 MODEL_OBJECTS = {v: k for (k, v) in OBJECT_TYPES.items()}
 
 TEST_OBJECTS: Dict[str, List[ModelObject]] = {}
 
 for object_type, objects in TEST_OBJECT_DICTS.items():
     converted_objects: List[ModelObject] = []
     model = MODEL_OBJECTS[object_type]
 
     for (num, obj_d) in enumerate(objects):
         if object_type == "origin_visit":
             obj_d = {**obj_d, "visit": num}
         elif object_type == "content":
-            obj_d = {**obj_d, "data": b"", "ctime": datetime.datetime.now()}
+            obj_d = {**obj_d, "data": b"", "ctime": datetime.datetime.now(tz=UTC)}
 
         converted_objects.append(model.from_dict(obj_d))
 
     TEST_OBJECTS[object_type] = converted_objects