Async JS test sample

createComponent.js

function criarComponente(name, type) {
  var events = {
    'onAfterLoad': [],
  };

  return {
    url: '',
    load: function () {
      $.getJSON(this.url).done(this._executeEvents('onAfterLoad'));
    },
    addEvent: function (event, callback) {
      events[event].push(callback);
    },
    _executeEvents: function (event) {
      var callbacks = events[event];

      return function(){
        var args = arguments;
        
        callbacks.forEach(function (cb) {
          cb.apply({}, args);
        });
      }
    }
  }
};

test.js

describe('my suite test', function () {
  var server;

  beforeEach(function () {
    server = sinon.fakeServer.create({ respondImmediately: false });
  });

  afterEach(function () {
    server.restore();
  });

  describe('my component data', function(){
    var ds, url = '/url/arquivo.json';

    beforeEach(function(){
      server.respondWith('GET', url,
        [200, { 'Content-Type': 'application/json' }]);
    
      ds = criarComponente('dst', 'DataSet');
      ds.url = url;
    });
  });
  
  it('should verify if the fake server return on load', function (done) {
    var response = { id: 1, comment: 'Hey there'};
    
    ds.addEvent('onAfterLoad', function (data) {
        expect(data).toBe(response);
        done();
    });

    ds.load();
    server.respond(response);
  });
});