jack

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h1. Introduction

Jack is a toolkit for mocking JavaScript objects and functions when writing tests. It is inspired by similar projects for Java and C#, like "JMock":http://www.jmock.org/, "Mockito":http://mockito.org/ and "Rhino Mocks":http://www.ayende.com/projects/rhino-mocks.aspx

Mocking can be achieved quite easily in JavaScript without help from a library, but anything above verifying that a function gets called can grow hard to read. If you have experienced this (or want to avoid it in the first place), Jack is for you.

h1. Contributions

Contributions are very welcome. Just fork "git://github.com/keronsen/jack.git":git://github.com/keronsen/jack.git and get started.

The head developer for Jack is "Karl-Erik Rønsen (keronsen)":http://github.com/keronsen/jack

Contributions have been received, accepted and appreciated from:

• "francois2metz":http://github.com/francois2metz/jack
• "duncanbeevers":http://github.com/duncanbeevers/jack

h1. Getting started

Download the latest version of Jack from github: "http://github.com/keronsen/jack":http://github.com/keronsen/jack General examples are found below. There are examples of use with different test frameworks in /docs/examples.

If you need help, there is a google group for discussion: "http://groups.google.com/group/jack-discuss":http://groups.google.com/group/jack-discuss

h1. Test framework integration

Jack is currently compatible with these JavaScript test frameworks:

• "JsTestDriver":http://code.google.com/p/js-test-driver/
• "QUnit":http://docs.jquery.com/QUnit
• "YUI Test":http://developer.yahoo.com/yui/yuitest/
• "JSSpec":http://jania.pe.kr/aw/moin.cgi/JSSpec (Also used for testing Jack itself)
• "Scriptaculous TestRunner":http://github.com/madrobby/scriptaculous/wikis/unit-testing

Integration is planned for these frameworks:

• "Screw.Unit":http://github.com/nathansobo/screw-unit

h1. Examples

For these examples, the application under test has a function storeSomething() that we expect will call the jQuery.post() function.

h3. Expect one call to function

bc. jack(function(){ jack.expect("jQuery.post").exactly("1 time"); storeSomething(); });

Available call quantifiers: never(), once(), exactly(), atLeast(), atMost()

h3. Expect argument values

bc. jack(function(){ jack.expect("jQuery.post") .exactly("1 time") .withArguments("http://example.com/service"); storeSomething(); });

h3. Set other argument constraints

bc. jack(function(){ jack.expect("jQuery.post") .exactly("1 time") .whereArgument(0).isOneOf("/serviceOne","/serviceTwo"); storeSomething(); });

Available constraint methods: is(), isNot(), isOneOf(), isType(), matches(), hasProperty(), hasProperties()

h3. Specifying a mock implementation of a function

bc. jack(function(){ jack.expect("jQuery.post") .exactly("1 time") .mock(function() { // your mock implementation }); storeSomething(); });

h3. Specifying a return value

bc. jack(function(){ jack.expect("jQuery.post") .exactly("1 time") .returnValue("The value to return."); storeSomething(); });

h3. Creating a mock object for testing interaction

If you want to test how your code under test interacts with other objects, you can create a mock object with @jack.create()@:

bc. jack(function(){ var myStack = jack.create("myStack", ['push','pop']); jack.expect("myStack.push") .exactly("1 time") .whereArgument(0).is("something"); useTheStack(myStack); });