dgellow/cow.js

## cow.js
if (!window.app) {
     window.app = {}
}

window.app.Cow = function(name) {
    this.name = name || 'Anon cow';
}

window.app.Cow.prototype = {
    greets: function(target) {
        if (!target) {
            throw new Error('missing target');
        }

        return this.name + ' greets ' + target;
    },

    lateGreets: function(target, callback) {
        setTimeout(function(self) {
            try {
                callback(null, self.greets(target));
            } catch (err) {
                callback(err);
            }
        }, 1000, this);
    }
}

## cow_test.js
var expect = chai.expect
, Cow = window.app.Cow;

describe('Cow', function() {
    describe('constructor', function() {
        it('should have a default name', function() {
            var cow = new Cow();
            expect(cow.name).to.equal('Anon cow');
        });

        it("should set cow's name if provided", function() {
            var cow = new Cow('Kate');
            expect(cow.name).to.equal('Kate');
        });
    })

    describe('#greets', function() {
        it('should throw if no target is passed in', function() {
            expect(function() {
                (new Cow()).greets();
            }).to.throw(Error);
        });

        it('should greet passed target', function() {
            var greetings = (new Cow('Kate')).greets('Baby');
            expect(greetings).to.equal('Kate greets Baby');
        });
    })

    describe('#lateGreets', function() {
        it('should pass an error if no target is passed', function(done) {
            (new Cow()).lateGreets(null, function(err, greetings) {
                expect(err).to.be.an.instanceof(Error);
                done();
            });
        });

        it('should greet passed target after one second', function(done) {
            (new Cow('Kate')).lateGreets('Baby', function(err, greetings) {
                expect(greetings).to.equal('Kate greets Baby');
                done();
            });
        });
    })
})

## main.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Cow tests</title>
    <link rel="stylesheet" media="all" href="vendor/mocha.css">
  </head>
  <body>
    <div id="mocha"><p><a href=".">Index</a></p></div>
    <div id="messages"></div>
    <div id="fixtures"></div>
    <script src="vendor/mocha.js"></script>
    <script src="vendor/chai.js"></script>
    <script src="models/cow.js"></script>
    <script>mocha.setup('bdd')</script>
    <script src="test/cow_test.js"></script>
    <script>mocha.run();</script>
  </body>
</html>
	if (!window.app) {
	window.app = {}
	}

	window.app.Cow = function(name) {
	this.name = name \|\| 'Anon cow';
	}

	window.app.Cow.prototype = {
	greets: function(target) {
	if (!target) {
	throw new Error('missing target');
	}

	return this.name + ' greets ' + target;
	},

	lateGreets: function(target, callback) {
	setTimeout(function(self) {
	try {
	callback(null, self.greets(target));
	} catch (err) {
	callback(err);
	}
	}, 1000, this);
	}
	}
	var expect = chai.expect
	, Cow = window.app.Cow;

	describe('Cow', function() {
	describe('constructor', function() {
	it('should have a default name', function() {
	var cow = new Cow();
	expect(cow.name).to.equal('Anon cow');
	});

	it("should set cow's name if provided", function() {
	var cow = new Cow('Kate');
	expect(cow.name).to.equal('Kate');
	});
	})

	describe('#greets', function() {
	it('should throw if no target is passed in', function() {
	expect(function() {
	(new Cow()).greets();
	}).to.throw(Error);
	});

	it('should greet passed target', function() {
	var greetings = (new Cow('Kate')).greets('Baby');
	expect(greetings).to.equal('Kate greets Baby');
	});
	})

	describe('#lateGreets', function() {
	it('should pass an error if no target is passed', function(done) {
	(new Cow()).lateGreets(null, function(err, greetings) {
	expect(err).to.be.an.instanceof(Error);
	done();
	});
	});

	it('should greet passed target after one second', function(done) {
	(new Cow('Kate')).lateGreets('Baby', function(err, greetings) {
	expect(greetings).to.equal('Kate greets Baby');
	done();
	});
	});
	})
	})
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>Cow tests</title>
	<link rel="stylesheet" media="all" href="vendor/mocha.css">
	</head>
	<body>
	<div id="mocha"><p><a href=".">Index</a></p></div>
	<div id="messages"></div>
	<div id="fixtures"></div>
	<script src="vendor/mocha.js"></script>
	<script src="vendor/chai.js"></script>
	<script src="models/cow.js"></script>
	<script>mocha.setup('bdd')</script>
	<script src="test/cow_test.js"></script>
	<script>mocha.run();</script>
	</body>
	</html>