Add e2e test for loading journal storage

e2e_tests/test_standalone/test_study_list.py

@@ -25,7 +25,7 @@ def test_home(
     assert title == "Optuna Dashboard (Wasm ver.)"
 
 
-def test_load_storage(
+def test_load_rdb_storage(
     page: Page,
     server_url: str,
 ) -> None:
@@ -69,3 +69,51 @@ def test_load_storage(
 
         count = count_components(page, "MuiCard-root")
         assert count == 4
+
+
+def test_load_journal_storage(
+    page: Page,
+    server_url: str,
+) -> None:
+    study_name = "single-objective"
+    url = f"{server_url}"
+
+    def create_storage_file(filename: str):
+        import optuna
+
+        storage = optuna.storages.JournalStorage(
+            optuna.storages.JournalFileStorage(f"{filename}"),
+        )
+        study = optuna.create_study(study_name=study_name, storage=storage)
+
+        def objective(trial: optuna.Trial) -> float:
+            x1 = trial.suggest_float("x1", 0, 10)
+            x2 = trial.suggest_float("x2", 0, 10)
+            return (x1 - 2) ** 2 + (x2 - 5) ** 2
+
+        study.optimize(objective, n_trials=100)
+
+    with tempfile.TemporaryDirectory() as dir:
+        with tempfile.NamedTemporaryFile() as fp:
+            filename = fp.name
+            path = os.path.join(dir, filename)
+            create_storage_file(filename)
+            page.goto(url)
+            with page.expect_file_chooser() as fc_info:
+                page.get_by_role("button").nth(2).click()
+            file_chooser = fc_info.value
+            file_chooser.set_files(path)
+
+        page.get_by_role("link", name=study_name).click()
+
+        def count_components(page: Page, component_name: str):
+            component_count = page.evaluate(
+                f"""() => {{
+                const components = document.querySelectorAll('.{component_name}');
+                return components.length;
+            }}"""
+            )
+            return component_count
+
+        count = count_components(page, "MuiCard-root")
+        assert count == 4