bogus

bogus is a small utility for stubbing dependencies when testing RequireJS based projects

Link Seam

In Working Effectively with Legacy Code, Michael Feathers describes Seams. In the vernacular of that book, bogus would be considered a Link Seam.

Getting bogus

You can install bogus into your project using either npm or bower

$ npm install bogus --save-dev

or

$ bower install bogus --save-dev

Usage

// SteeringWheel
define('SteeringWheel', function(){
    function SteeringWheel(){
        this.color = 'black';
    }

    return SteeringWheel;
});

// Car
define('Car', ['SteeringWheel'], function(SteeringWheel){
    function Car(){
        this.steeringWheel = new SteeringWheel();
    }

    Car.prototype.getSteeringWheelColor = function getSteeringWheelColor(){
        return this.steeringWheel.color;
    };

    return Car;
});

// load bogus
define([
    'bower_components/bogus/bogus'  // this is ofc. dependent on where you installed it
], function(
    bogus
){
    describe('myModule', function{
        var Car;

        beforeEach(function(done){
            var fakeSteeringWheel = function(){
                this.color = 'blue';
            };

            // stub out a dependency (SteeringWheel) with our fake
            bogus.stub('SteeringWheel', fakeSteeringWheel);

            // load Car module, that depends on SteeringWheel
            bogus.require('Car', function(module){
                Car = module;
                done();
            });
        });

        afterEach(function(done){
            bogus.reset(done);
        });

        describe('Car', function(){
            describe('getSteeringWheelColor method', function(){
                it('should return the actual color of the SteeringWheel', function(){
                    var car = new Car();

                    assert.equal(car.getSteeringWheelColor(), 'blue');
                });
            });
        });
    });
});

Promises

Both bogus.require and bogus.reset return promises. The beforeEach and afterEach in the example above can be written as:

beforeEach(function(){
    var fakeSteeringWheel = function(){
        this.color = 'blue';
    };

    bogus.stub('SteeringWheel', fakeSteeringWheel);

    return bogus.require('Car').then(function(module){
        Car = module;
    });
});

afterEach(function(){
    return bogus.reset();
});

Stub multiple dependencies

If you're stubbing several dependencies, you can pass a map of them to stub

var firstFake = {};
var secondFake = {};

bogus.stub({
    'path/to/first/dependency': firstFake,
    'path/to/second/dependency': secondFake
});

Development

You can run the tests with

$ npm test

or with

$ mocha

if you have mocha installed as a global

See also

• Injecting Stubs/Mocks into Tests with Require.js - the blog post that laid the groundwork for what became bogus
• Squire.js - also stubs out RequireJS dependencies. I couldn't get it to stop re-downloading all the dependencies for each test ... nor could someone else

License

MIT: http://mrgnrdrck.mit-license.org