diff --git a/swh/lister/puppet/__init__.py b/swh/lister/puppet/__init__.py
--- a/swh/lister/puppet/__init__.py
+++ b/swh/lister/puppet/__init__.py
@@ -38,7 +38,7 @@
 
     "https://forge.puppet.com/modules/{owner}/{pkgname}"
 
-For each origin `last_update`is set via the module "updated_at" value.
+For each origin `last_update` is set via the module "updated_at" value.
 As the api also returns all existing versions for a package, we build an `artifacts`
 dict in `extra_loader_arguments` with the archive tarball corresponding to each
 existing versions.
@@ -47,20 +47,27 @@
 https://forge.puppet.com/modules/electrical/file_concat::
 
     {
-        "artifacts": {
-            "1.0.0": {
-                "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.0.tar.gz",  # noqa: B950
-                "version": "1.0.0",
-                "filename": "electrical-file_concat-1.0.0.tar.gz",
-                "last_update": "2015-04-09T12:03:13-07:00",
-            },
-            "1.0.1": {
+        "artifacts": [
+            {
                 "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.1.tar.gz",  # noqa: B950
                 "version": "1.0.1",
                 "filename": "electrical-file_concat-1.0.1.tar.gz",
                 "last_update": "2015-04-17T01:03:46-07:00",
+                "checksums": {
+                    "md5": "74901a89544134478c2dfde5efbb7f14",
+                    "sha256": "15e973613ea038d8a4f60bafe2d678f88f53f3624c02df3157c0043f4a400de6",  # noqa: B950
+                },
+            },
+            {
+                "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.0.tar.gz",  # noqa: B950
+                "version": "1.0.0",
+                "filename": "electrical-file_concat-1.0.0.tar.gz",
+                "last_update": "2015-04-09T12:03:13-07:00",
+                "checksums": {
+                    "length": 13289,
+                },
             },
-        }
+        ],
     }
 
 Running tests
diff --git a/swh/lister/puppet/lister.py b/swh/lister/puppet/lister.py
--- a/swh/lister/puppet/lister.py
+++ b/swh/lister/puppet/lister.py
@@ -76,7 +76,7 @@
             pkgname = entry["name"]
             owner = entry["owner"]["slug"]
             url = f"https://forge.puppet.com/modules/{owner}/{pkgname}"
-            artifacts = {}
+            artifacts = []
             for release in entry["releases"]:
                 # Build an artifact entry following original-artifacts-json specification
                 # https://docs.softwareheritage.org/devel/swh-storage/extrinsic-metadata-specification.html#original-artifacts-json  # noqa: B950
@@ -92,15 +92,17 @@
                     # use file length as basic content check instead
                     checksums["length"] = release["file_size"]
 
-                artifacts[release["version"]] = {
-                    "filename": release["file_uri"].split("/")[-1],
-                    "url": urljoin(self.BASE_URL, release["file_uri"]),
-                    "version": release["version"],
-                    "last_update": datetime.strptime(
-                        release["created_at"], dt_parse_pattern
-                    ).isoformat(),
-                    "checksums": checksums,
-                }
+                artifacts.append(
+                    {
+                        "filename": release["file_uri"].split("/")[-1],
+                        "url": urljoin(self.BASE_URL, release["file_uri"]),
+                        "version": release["version"],
+                        "last_update": datetime.strptime(
+                            release["created_at"], dt_parse_pattern
+                        ).isoformat(),
+                        "checksums": checksums,
+                    }
+                )
 
             yield ListedOrigin(
                 lister_id=self.lister_obj.id,
diff --git a/swh/lister/puppet/tests/test_lister.py b/swh/lister/puppet/tests/test_lister.py
--- a/swh/lister/puppet/tests/test_lister.py
+++ b/swh/lister/puppet/tests/test_lister.py
@@ -7,19 +7,11 @@
 
 # flake8: noqa: B950
 
-expected_origins = {
-    "https://forge.puppet.com/modules/electrical/file_concat": {
-        "artifacts": {
-            "1.0.0": {
-                "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.0.tar.gz",
-                "version": "1.0.0",
-                "filename": "electrical-file_concat-1.0.0.tar.gz",
-                "last_update": "2015-04-09T12:03:13-07:00",
-                "checksums": {
-                    "length": 13289,
-                },
-            },
-            "1.0.1": {
+expected_origins = [
+    {
+        "url": "https://forge.puppet.com/modules/electrical/file_concat",
+        "artifacts": [
+            {
                 "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.1.tar.gz",
                 "version": "1.0.1",
                 "filename": "electrical-file_concat-1.0.1.tar.gz",
@@ -29,29 +21,21 @@
                     "sha256": "15e973613ea038d8a4f60bafe2d678f88f53f3624c02df3157c0043f4a400de6",
                 },
             },
-        }
-    },
-    "https://forge.puppet.com/modules/puppetlabs/puppetdb": {
-        "artifacts": {
-            "1.0.0": {
-                "url": "https://forgeapi.puppet.com/v3/files/puppetlabs-puppetdb-1.0.0.tar.gz",
+            {
+                "url": "https://forgeapi.puppet.com/v3/files/electrical-file_concat-1.0.0.tar.gz",
                 "version": "1.0.0",
-                "filename": "puppetlabs-puppetdb-1.0.0.tar.gz",
-                "last_update": "2012-09-19T16:51:22-07:00",
-                "checksums": {
-                    "length": 16336,
-                },
-            },
-            "7.9.0": {
-                "url": "https://forgeapi.puppet.com/v3/files/puppetlabs-puppetdb-7.9.0.tar.gz",
-                "version": "7.9.0",
-                "filename": "puppetlabs-puppetdb-7.9.0.tar.gz",
-                "last_update": "2021-06-24T07:48:54-07:00",
+                "filename": "electrical-file_concat-1.0.0.tar.gz",
+                "last_update": "2015-04-09T12:03:13-07:00",
                 "checksums": {
-                    "length": 42773,
+                    "length": 13289,
                 },
             },
-            "7.10.0": {
+        ],
+    },
+    {
+        "url": "https://forge.puppet.com/modules/puppetlabs/puppetdb",
+        "artifacts": [
+            {
                 "url": "https://forgeapi.puppet.com/v3/files/puppetlabs-puppetdb-7.10.0.tar.gz",
                 "version": "7.10.0",
                 "filename": "puppetlabs-puppetdb-7.10.0.tar.gz",
@@ -61,20 +45,30 @@
                     "sha256": "49b1a542fbd2a1378c16cb04809e0f88bf4f3e45979532294fb1f03f56c97fbb",
                 },
             },
-        }
-    },
-    "https://forge.puppet.com/modules/saz/memcached": {
-        "artifacts": {
-            "1.0.0": {
-                "url": "https://forgeapi.puppet.com/v3/files/saz-memcached-1.0.0.tar.gz",
+            {
+                "url": "https://forgeapi.puppet.com/v3/files/puppetlabs-puppetdb-7.9.0.tar.gz",
+                "version": "7.9.0",
+                "filename": "puppetlabs-puppetdb-7.9.0.tar.gz",
+                "last_update": "2021-06-24T07:48:54-07:00",
+                "checksums": {
+                    "length": 42773,
+                },
+            },
+            {
+                "url": "https://forgeapi.puppet.com/v3/files/puppetlabs-puppetdb-1.0.0.tar.gz",
                 "version": "1.0.0",
-                "filename": "saz-memcached-1.0.0.tar.gz",
-                "last_update": "2011-11-20T13:40:30-08:00",
+                "filename": "puppetlabs-puppetdb-1.0.0.tar.gz",
+                "last_update": "2012-09-19T16:51:22-07:00",
                 "checksums": {
-                    "length": 2472,
+                    "length": 16336,
                 },
             },
-            "8.1.0": {
+        ],
+    },
+    {
+        "url": "https://forge.puppet.com/modules/saz/memcached",
+        "artifacts": [
+            {
                 "url": "https://forgeapi.puppet.com/v3/files/saz-memcached-8.1.0.tar.gz",
                 "version": "8.1.0",
                 "filename": "saz-memcached-8.1.0.tar.gz",
@@ -84,9 +78,18 @@
                     "sha256": "883d6186e91c2c3fed13ae2009c3aa596657f6707b76f1f7efc6203c6e4ae986",
                 },
             },
-        }
+            {
+                "url": "https://forgeapi.puppet.com/v3/files/saz-memcached-1.0.0.tar.gz",
+                "version": "1.0.0",
+                "filename": "saz-memcached-1.0.0.tar.gz",
+                "last_update": "2011-11-20T13:40:30-08:00",
+                "checksums": {
+                    "length": 2472,
+                },
+            },
+        ],
     },
-}
+]
 
 
 def test_puppet_lister(datadir, requests_mock_datadir, swh_scheduler):
@@ -100,7 +103,18 @@
 
     assert len(scheduler_origins) == len(expected_origins)
 
-    for origin in scheduler_origins:
-        assert origin.visit_type == "puppet"
-        assert origin.url in expected_origins
-        assert origin.extra_loader_arguments == expected_origins[origin.url]
+    assert [
+        (
+            scheduled.visit_type,
+            scheduled.url,
+            scheduled.extra_loader_arguments["artifacts"],
+        )
+        for scheduled in sorted(scheduler_origins, key=lambda scheduled: scheduled.url)
+    ] == [
+        (
+            "puppet",
+            expected["url"],
+            expected["artifacts"],
+        )
+        for expected in sorted(expected_origins, key=lambda expected: expected["url"])
+    ]