Testcase for memory leak on widgets

main.js

const widgets = require("widget");
const timer = require("timer");

var instance = 0;
var widget = widgets.Widget({
    label: "Mozilla website",
    content: instance.toString(),
    onClick: function() {
      tabs.open("http://www.mozilla.org/");
    }
  });

timer.setInterval(function(){
  widget.destroy();
  instance++;
  widget = widgets.Widget({
    label: "Mozilla website",
    content: instance.toString(),
    onClick: function() {
      tabs.open("http://www.mozilla.org/");
    }
  });
}, 1000);