Bootstrap/js/tests/unit/affix.js

$(function () {

    module('affix')

      test('should provide no conflict', function () {
        var affix = $.fn.affix.noConflict()
        ok(!$.fn.affix, 'affix was set back to undefined (org value)')
        $.fn.affix = affix
      })

      test('should be defined on jquery object', function () {
        ok($(document.body).affix, 'affix method is defined')
      })

      test('should return element', function () {
        ok($(document.body).affix()[0] == document.body, 'document.body returned')
      })

      test('should exit early if element is not visible', function () {
        var $affix = $('<div style="display: none"></div>').affix()
        $affix.data('bs.affix').checkPosition()
        ok(!$affix.hasClass('affix'), 'affix class was not added')
      })

      test('should trigger affixed event after affix', function () {
        stop()

        var template = $('<div id="affixTarget"><ul><li>Please affix</li><li>And unaffix</li></ul></div><div id="affixAfter" style="height: 20000px; display:block;"></div>')
        template.appendTo('body')

        var affixer = $('#affixTarget').affix({
          offset: $('#affixTarget ul').position()
        })

        $('#affixTarget')
          .on('affix.bs.affix', function (e) {
            ok(true, 'affix event triggered')
          }).on('affixed.bs.affix', function (e) {
            ok(true,'affixed event triggered')
            $('#affixTarget').remove()
            $('#affixAfter').remove()
            start()
          })

        setTimeout(function () {
          window.scrollTo(0, document.body.scrollHeight)
          setTimeout(function () { window.scroll(0,0) }, 0)
        },0)
      })
})