### Question:
ClassicOptionHelper extends AbstractOptionHelper { @Override public ChartOptions addTitle(ChartOptions parent, IModel<String> titleModel) { parent.put("title", titleModel); return parent; } ClassicOptionHelper(Chart chart); @Override ChartOptions addTitle(ChartOptions parent, IModel<String> titleModel); @Override ChartOptions addTitle(ChartOptions parent, String title); @Override ChartOptions addSubTitle(ChartOptions parent, IModel<String> titleModel); @Override ChartOptions addSubTitle(ChartOptions parent, String subTitle); @Override ChartOptions addDualAxisOptions(ChartOptions parent,
            String[] axisNames, String[] seriesMapping, String[] axisTitles,
            OptionModifier[] axisModifiers, OptionModifier[] seriesModifiers);  }### Answer:
@Test public void testAddTitleOption() { ChartOptions parent = new ChartOptions(); ClassicOptionHelper instance = new ClassicOptionHelper(chart); String expResult = "{\"title\":\"Chart Title\"}"; ChartOptions result = instance.addTitle(parent, "Chart Title"); assertJsonEquals(expResult, result.toJSON().toString()); }