assertEquals("{labels.index_lang}", FessLabels.LABELS_index_lang);
        assertEquals("{labels.index_sort}", FessLabels.LABELS_index_sort);
        assertEquals("{labels.index_num}", FessLabels.LABELS_index_num);

        // Test error related labels
        assertEquals("{labels.error_title}", FessLabels.LABELS_error_title);

    }

    @Test
    public void testSpecialCharactersInIndexName() {
        // Test index name with special characters
        builder.setSettingsIndexName("Test-Index_Name.2024");
        assertEquals("test-index_name.2024", builder.settingsIndexName);

        // Test index name with spaces (should be lowercased)
        builder.setSettingsIndexName("Test Index Name");