test('should return all the registered widget names', () => {
     WidgetClassRegistry.registerWidgetClass('foo', fooWidgetClass);
     WidgetClassRegistry.registerWidgetClass('bar', barWidgetClass);
     expect(WidgetClassRegistry.getRegisteredWidgetNames()).toEqual(['foo', 'bar']);
 });
 test('should return the same widget class that was registered previously with the same name', () => {
     WidgetClassRegistry.registerWidgetClass('foo', fooWidgetClass);
     expect(WidgetClassRegistry.getWidgetClass('foo')).toBe(fooWidgetClass);
 });