test.js

  QUnit.test('should add the active class correctly when there are nested elements at 0 scroll offset', function (assert) {
    var times = 0
    var done = assert.async()
    var navbarHtml = '<nav class="navbar">'
        + '<ul class="nav">'
        + '<li id="li-1"><a href="#div-1">div 1</a>'
        + '<ul>'
        + '<li id="li-2"><a href="#div-2">div 2</a></li>'
        + '</ul>'
        + '</li>'
        + '</ul>'
        + '</nav>'
    var contentHtml = '<div class="content" style="position: absolute; top: 0px; overflow: auto; height: 50px">'
        + '<div id="div-1" style="padding: 0; margin: 0">'
        + '<div id="div-2" style="height: 200px; padding: 0; margin: 0">div 2</div>'
        + '</div>'
        + '</div>'

    $(navbarHtml).appendTo('#qunit-fixture')

    var $content = $(contentHtml)
      .appendTo('#qunit-fixture')
      .bootstrapScrollspy({ offset: 0, target: '.navbar' })

    !function testActiveElements() {
      if (++times == 2) return done()

      $content.one('scroll', function () {
        assert.ok($('#li-1').hasClass('active'), 'nav item for outer element has "active" class')
        assert.ok($('#li-2').hasClass('active'), 'nav item for inner element has "active" class')
        testActiveElements()
      })

      $content.scrollTop($content.scrollTop() + 10)
    }()
  })