test.js

var testRetryCounter = 0;
var assert = chai.assert;

$.ajax = function(opts) {
  testRetryCounter++;
  setTimeout(opts.error, 0);
};

var real_setTimeout = setTimeout;

setTimeout = function(code, timeout ) {
  real_setTimeout(code, 0);
};

describe('Data', function() {
  describe('#sendData()', function() {
    it('should retry 3 times before quitting', function(done) {
      var p = new PersonalData();
      p.sendData();
      real_setTimeout(function() {
        assert.equal(testRetryCounter, 3);
        done();
      }, 100);

    });
  });
});