Add optuna_dashboard.preferential module

python_tests/preferential/test_system_attrs.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from typing import Callable
+
+import optuna
+from optuna_dashboard.preferential._system_attrs import get_preferences
+from optuna_dashboard.preferential._system_attrs import report_preferences
+
+from ..storage_supplier import parametrize_storages
+from ..storage_supplier import StorageSupplier
+
+
+@parametrize_storages
+def test_report_and_get_preferences(storage_supplier: Callable[[], StorageSupplier]) -> None:
+    with storage_supplier() as storage:
+        study = optuna.create_study(storage=storage)
+        study.ask()
+        study.ask()
+
+        assert len(get_preferences(study)) == 0
+
+        better, worse = study.trials[0], study.trials[1]
+        report_preferences(study, [(better, worse)])
+        assert len(get_preferences(study)) == 1
+
+        actual_better, actual_worse = get_preferences(study)[0]
+        assert actual_better.number == better.number
+        assert actual_worse.number == worse.number