I’m diving into unit testing with Node.js, and my first stop is nodeunit. Luckily, Caolan McMahon wrote an excellent introduction to nodeunit on his blog. Thanks, Caolan.

I installed nodeunit via npm no problem: npm install nodeunit

All the examples in the Installing nodeunit section worked fine, but I needed to add
var events = require('events');
to the first code sample in the Testing asynchronous code section to get those tests to pass. So, the top of my test-doubled.js file looks like:

var doubled = require('../lib/doubled');
var events = require('events');
...

Farther down in the blog post, in the Shared state and sequential testing section, there’s a code sample with the events include in it, so I think I’m on the right track.

In the Test cases, setUp and tearDown section, I had trouble getting the tests to run. After referencing the project’s README file, I tried adding a callback arg to setUp() and tearDown(), and calling the callback, which worked. So, my code looks like:

...

var testCase = require('nodeunit').testCase;

exports.read = testCase({
setUp: function (callback) {
this._openStdin = process.openStdin;
this._log = console.log;
this._calculate = doubled.calculate;
this._exit = process.exit;

var ev = this.ev = new events.EventEmitter();
process.openStdin = function () { return ev; };

callback();
},
tearDown: function (callback) {
// reset all the overidden functions:
process.openStdin = this._openStdin;
process.exit = this._exit;
doubled.calculate = this._calculate;
console.log = this._log;

callback();
},
...

With the minor tweaks above, I was able to get all tests to pass:

🙂