test.timer.js

var   sinon     = require('sinon');
var   chai      = require('chai');

 expect = chai.expect;
 should = chai.should();
 assert = chai.assert;

var clock;
beforeEach(function () {
    clock = sinon.useFakeTimers();
});

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

it("should time out after 5000 ms", function() {
    var timedOut = false;
    setTimeout(function () {
        console.log('executed!');
        timedOut = true;
    }, 5000);

    timedOut.should.be.false;
    clock.tick(5500);
    timedOut.should.be.true;
});