Mocha

A framework for easily creating beautiful unit test using javascript

Presentation by Felipe F. Lima / @felipefdlima

Features

browser support

simple async support

string diff support

javascript API for running tests

auto-detects and disables coloring for non-ttys

reports test durations

highlights slow tests

file watcher support

node debugger support

use any assertion library you want

and... More... Very More

proper exit status for CI support etc

maps uncaught exceptions to the correct test case

async test timeout support

test-specific timeouts

growl notification support

global variable leak detection

optionally run tests that match a regexp

auto-exit to prevent "hanging" with an active loop

easily meta-generate suites & test-cases

mocha.opts file support

clickable suite titles to filter test execution

detects multiple calls to done()

use any assertion library you want

extensible reporting, bundled with 9+ reporters

extensible test DSLs or "interfaces"

before, after, before each, after each hooks

arbitrary transpiler support (coffee-script etc)

TextMate bundle

...

Hello Test World

This is a first test in Mocha


var assert = require("assert");

describe('Array', function(){
  describe('#indexOf()', function(){
    it('should return -1 when the value is not present', function(){
      assert.equal(-1, [1,2,3].indexOf(5));
      assert.equal(-1, [1,2,3].indexOf(0));
    });
  });
});

Asynchronous code

Testing asynchronous code with Mocha could not be simpler! Simply invoke the callback when your test is complete. By adding a callback (usually named done) to it() Mocha will know that it should wait for completion.


describe('User', function(){
  describe('#save()', function(){
    it('should save without error', function(done){
      var user = new User('Luna');
      user.save(function(err){
        if (err) throw err;
        done();
      });
    });
  });
});

Avoid code duplication

All "hooks", that is before(), after(), beforeEach(), afterEach() may be sync or async as well, behaving much like a regular test-case.


describe('Connection', function(){
  var db = new Connection,
      tobi = new User('tobi'),
      loki = new User('loki'),
      jane = new User('jane');

  beforeEach(function(done){
    db.clear(function(err){
      if (err) return done(err);
      db.save([tobi, loki, jane], done);
    });
  });

  describe('#find()', function(){
    it('respond with matching records', function(done){
      db.find({ type: 'User' }, function(err, res){
        if (err) return done(err);
        res.should.have.length(3);
        done();
      });
    });
  });
});

Beautiful! Now, how to start this test?

1. You need NODE.JS

2. You need Mocha


							npm install -g mocha

3. And run


							mocha test.js

4. By default mocha will use the pattern "./test/*.js", so it's usually a good place to put your tests.


							mocha

Browser support

Mocha runs in the browser.


<html>
<head>
  <meta charset="utf-8">
  <title>Mocha Tests</title>
  <link rel="stylesheet" href="mocha.css" />
</head>
<body>
  <div id="mocha"></div>
  <script src="jquery.js"></script>
  <script src="expect.js"></script>
  <script src="mocha.js"></script>
  <script>mocha.setup('bdd')</script>
  <script src="test.array.js"></script>
  <script src="test.object.js"></script>
  <script src="test.xhr.js"></script>
  <script>
    mocha.checkLeaks();
    mocha.globals(['jQuery']);
    mocha.run();
  </script>
</body>
</html>