diff --git a/tests/unit/test_notifier.py b/tests/unit/test_notifier.py
index 08db9a75eb..93244b7211 100644
--- a/tests/unit/test_notifier.py
+++ b/tests/unit/test_notifier.py
@@ -123,7 +123,7 @@ def test_notify_image_flag_public(mocker, monkeypatch):
             "user_id": "roboto-app",
             "source": "robotoff",
             "confidence": None,
-            "image_id": 2,
+            "image_id": "2",
             "flavor": "off",
             "comment": '{"text": "bad_word", "type": "SENSITIVE", "label": "flagged"}',
         },
@@ -171,7 +171,7 @@ def test_notify_image_flag_private(mocker, monkeypatch):
             "url": "https://images.openfoodfacts.net/images/products/source_image/2.jpg",
             "user_id": "roboto-app",
             "source": "robotoff",
-            "image_id": 2,
+            "image_id": "2",
             "flavor": "off",
             "comment": '{"type": "label_annotation", "label": "face", "likelihood": 0.8}',
             "confidence": 0.8,