diff --git a/swh/model/tests/swh_model_data.py b/swh/model/tests/swh_model_data.py
index 2e0f1529620583e2bf58cac20879323e1ad66773..5c4fcdda9908f0200fb2558f4242abce2af9a909 100644
--- a/swh/model/tests/swh_model_data.py
+++ b/swh/model/tests/swh_model_data.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019-2021 The Software Heritage developers
+# Copyright (C) 2019-2025 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
@@ -18,7 +18,6 @@ from swh.model.model import (
     MetadataAuthority,
     MetadataAuthorityType,
     MetadataFetcher,
-    ModelObjectType,
     ObjectType,
     Origin,
     OriginVisit,
@@ -449,7 +448,7 @@ EXTIDS: List[ExtID] = [
     ),
 ]
 
-TEST_OBJECTS: Dict[ModelObjectType, Sequence[BaseModel]] = {}
+TEST_OBJECTS: Dict[str, Sequence[BaseModel]] = {}
 # generate this mapping with code to avoid error
 for objects in [
     CONTENTS,
@@ -467,8 +466,8 @@ for objects in [
     SKIPPED_CONTENTS,
 ]:
     objects = cast(List[BaseModel], objects)
-    object_type = objects[0].object_type
-    assert all(object_type == o.object_type for o in objects)
+    object_type = objects[0].object_type.value
+    assert all(object_type == o.object_type.value for o in objects)
     assert object_type not in TEST_OBJECTS
     TEST_OBJECTS[object_type] = objects
 
diff --git a/swh/model/tests/test_model.py b/swh/model/tests/test_model.py
index a50b3369fd0c5550513d8776c5de2014472a5a64..cf91ec3da442d5cd1b117c7b37788b4eb5efaafe 100644
--- a/swh/model/tests/test_model.py
+++ b/swh/model/tests/test_model.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019-2020 The Software Heritage developers
+# Copyright (C) 2019-2025 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
@@ -327,8 +327,8 @@ def test_optimized_type_validator_invalid(type_, value):
         validator(None, attr.ib(type=type_), value)
 
 
-@pytest.mark.parametrize("object_type, objects", TEST_OBJECTS.items())
-def test_swh_model_todict_fromdict(object_type, objects):
+@pytest.mark.parametrize("objects", TEST_OBJECTS.values())
+def test_swh_model_todict_fromdict(objects):
     """checks model objects in swh_model_data are in correct shape"""
     assert objects
     for obj in objects:
diff --git a/swh/model/tests/test_swh_model_data.py b/swh/model/tests/test_swh_model_data.py
index 3815c487540d0d01ea4c24952e598b6bea53641c..2877827f64ec113771f902d4776256d30d11b308 100644
--- a/swh/model/tests/test_swh_model_data.py
+++ b/swh/model/tests/test_swh_model_data.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2021  The Software Heritage developers
+# Copyright (C) 2021-2025  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
@@ -6,7 +6,14 @@
 import attr
 import pytest
 
-from swh.model.model import ModelObjectType
+from swh.model.model import (
+    Directory,
+    OriginVisit,
+    OriginVisitStatus,
+    Release,
+    Revision,
+    Snapshot,
+)
 from swh.model.tests.swh_model_data import TEST_OBJECTS
 
 
@@ -15,17 +22,17 @@ def test_swh_model_data(object_type, objects):
     """checks model objects in swh_model_data are in correct shape"""
     assert objects
     for obj in objects:
-        assert obj.object_type == object_type
+        assert obj.object_type.value == object_type
         attr.validate(obj)
 
 
 @pytest.mark.parametrize(
     "object_type",
     (
-        ModelObjectType.DIRECTORY,
-        ModelObjectType.REVISION,
-        ModelObjectType.RELEASE,
-        ModelObjectType.SNAPSHOT,
+        Directory.object_type.value,
+        Revision.object_type.value,
+        Release.object_type.value,
+        Snapshot.object_type.value,
     ),
 )
 def test_swh_model_data_hash(object_type):
@@ -44,8 +51,8 @@ def test_ensure_visit_status_date_consistency():
     parameters from the origin-visit {origin, visit, date}...
 
     """
-    visits = TEST_OBJECTS[ModelObjectType.ORIGIN_VISIT]
-    visit_statuses = TEST_OBJECTS[ModelObjectType.ORIGIN_VISIT_STATUS]
+    visits = TEST_OBJECTS[OriginVisit.object_type.value]
+    visit_statuses = TEST_OBJECTS[OriginVisitStatus.object_type.value]
     for visit, visit_status in zip(visits, visit_statuses):
         assert visit.origin == visit_status.origin
         assert visit.visit == visit_status.visit
@@ -54,7 +61,7 @@ def test_ensure_visit_status_date_consistency():
 
 def test_ensure_visit_status_snapshot_consistency():
     """ensure origin-visit-status snapshots exist in the test dataset"""
-    snapshots = [snp.id for snp in TEST_OBJECTS[ModelObjectType.SNAPSHOT]]
-    for visit_status in TEST_OBJECTS[ModelObjectType.ORIGIN_VISIT_STATUS]:
+    snapshots = [snp.id for snp in TEST_OBJECTS[Snapshot.object_type.value]]
+    for visit_status in TEST_OBJECTS[OriginVisitStatus.object_type.value]:
         if visit_status.snapshot:
             assert visit_status.snapshot in snapshots