diff --git a/python_tests/artifact/test_backend.py b/python_tests/artifact/test_backend.py
index 22544e6f..00e55d51 100644
--- a/python_tests/artifact/test_backend.py
+++ b/python_tests/artifact/test_backend.py
@@ -1,9 +1,16 @@
+import tempfile
 from unittest.mock import MagicMock
 
+import optuna
+from optuna.artifacts import FileSystemArtifactStore
+from optuna.artifacts import upload_artifact
 from optuna.storages import BaseStorage
+from optuna_dashboard._app import create_app
 from optuna_dashboard.artifact import _backend
 import pytest
 
+from ..wsgi_client import send_request
+
 
 def test_get_artifact_path() -> None:
     study = MagicMock(_study_id=0)
@@ -80,3 +87,50 @@ def test_list_trial_artifacts(init_storage_with_artifact_meta: MagicMock) -> Non
         {"artifact_id": "id1", "filename": "bar.txt"},
         {"artifact_id": "id2", "filename": "baz.txt"},
     ]
+
+
+def test_artifact_store_none() -> None:
+    storage = optuna.storages.InMemoryStorage()
+    app = create_app(storage)
+    status, _, body = send_request(
+        app,
+        "/artifacts/0/0",
+        "GET",
+        content_type="application/json",
+    )
+    assert status == 400
+
+
+def test_artifact_not_found() -> None:
+    storage = optuna.storages.InMemoryStorage()
+    study = optuna.create_study(storage=storage)
+    with tempfile.TemporaryDirectory() as tmpdir:
+        artifact_store = FileSystemArtifactStore(tmpdir)
+        app = create_app(storage, artifact_store)
+        status, _, body = send_request(
+            app,
+            f"/artifacts/{study._study_id}/abc123",
+            "GET",
+            content_type="application/json",
+        )
+        assert status == 404
+
+
+def test_successful_artifact_retrieval() -> None:
+    storage = optuna.storages.InMemoryStorage()
+    study = optuna.create_study(storage=storage)
+    with tempfile.TemporaryDirectory() as tmpdir:
+        artifact_store = FileSystemArtifactStore(tmpdir)
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b"dummy_content")
+            f.flush()
+            artifact_id = upload_artifact(study, f.name, artifact_store=artifact_store)
+        app = create_app(storage, artifact_store)
+        status, _, body = send_request(
+            app,
+            f"/artifacts/{study._study_id}/{artifact_id}",
+            "GET",
+            content_type="application/json",
+        )
+        assert status == 200
+        assert body == b"dummy_content"