Thursday, September 1, 2011

Unit Testing a jQuery Plugin with CoffeeScript and Pavlov

If you search the web, you'll find a handful of good examples of jQuery plugins written in CoffeeScript, but there seems to be few examples of writing unit tests/specs in CoffeeScript. In this post, I'll show a very simple jQuery plugin with Pavlov specs.

Simple Plugin

This plugin simply wraps the jQuery UI dialog (http://jqueryui.com/demos/dialog/).
do ($ = jQuery) ->
  methods = 
    init: (options) ->
      dialogElement = $(options.dialogSelector)
      dialog = dialogElement.dialog autoOpen: false, modal: true, resizable: false 
      $(options.inputSelector).click -> dialog.dialog 'open'
  
  $.fn.simple = (options) -> 
    settings = dialogSelector:'.dialog', inputSelector:'.input'
    if options 
      $.extend settings, options
    methods.init settings
Pavlov Specs

QUnit is a JavaScript testing framework (learn more about it at http://docs.jquery.com/Qunit) and Pavlov (https://github.com/mmonteleone/pavlov) extends QUnit with several features that promote Behavior-Driven Development (BDD). Here's the example:
pavlov.specify "Simple Plugin", ->
  describe "Given default options", -> 
    before -> $(this).simple()
    describe "when executing a click event", ->
      before -> $('.input').click()
      it "it should open the dialog", ->
        assert($('.dialog').parents('.ui-dialog:visible').length).isTrue()
      after ->
        $('.dialog').dialog('close')
    describe "When the click event has not been executed", ->
      it "it should not have an open dialog", ->
        assert($('.dialog').parents('.ui-dialog:visible').length).isFalse()
      after -> 
        $('.dialog').dialog('close')

  describe "Given all custom options", -> 
    before -> 
      $(this).simple dialogSelector:'.customDialog', inputSelector:'.customInput' 
    describe "when executing a click event", ->
      before -> $('.customInput').click()
      it "it should open the custom dialog", ->
        assert($('.customDialog').parents('.ui-dialog:visible').length).isTrue()
      after ->
        $('.customDialog').dialog('close')

  describe "Given only a custom dialogSelector", -> 
    before -> $(this).simple dialogSelector:'.customDialog'
    describe "when executing a click event", ->
      before -> $('.input').click()
      it "it should open the custom dialog", ->
        assert($('.customDialog').parents('.ui-dialog:visible').length).isTrue()
      after ->
        $('.customDialog').dialog('close')

  describe "Given only a custom inputSelector", -> 
    before -> $(this).simple inputSelector:'.customInput' 
    describe "when executing a click event", ->
      before -> $('.customInput').click()
      it "it should open the dialog", ->
        assert($('.dialog').parents('.ui-dialog:visible').length).isTrue()
      after ->
        $('.dialog').dialog('close')
The Output

Once we have this in place and create a simple test runner page, we end up with the standard QUnit output that looks like the following:

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