add is_preferential flag to study summary API

python_tests/test_serializers.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import optuna
 from optuna_dashboard._serializer import serialize_attrs
 from optuna_dashboard._serializer import serialize_study_detail
+from optuna_dashboard._serializer import serialize_study_summary
 from optuna_dashboard._storage import get_study_summaries
 from optuna_dashboard.preferential import create_study
 
@@ -41,3 +42,22 @@ def test_get_study_detail_is_not_preferential() -> None:
     study_summary = study_summaries[0]
     study_detail = serialize_study_detail(study_summary, [], study.trials, [], [], [], False)
     assert not study_detail["is_preferential"]
+
+
+def test_get_study_summary_is_preferential() -> None:
+    storage = optuna.storages.InMemoryStorage()
+    create_study(storage=storage)
+    study_summaries = get_study_summaries(storage)
+    assert len(study_summaries) == 1
+
+    study_summary = serialize_study_summary(study_summaries[0])
+    assert study_summary["is_preferential"]
+
+
+def test_get_study_summary_is_not_preferential() -> None:
+    storage = optuna.storages.InMemoryStorage()
+    optuna.create_study(storage=storage)
+    study_summaries = get_study_summaries(storage)
+    assert len(study_summaries) == 1
+    study_summary = serialize_study_summary(study_summaries[0])
+    assert not study_summary["is_preferential"]