 
     describe '.hidden()', ->
 
-      it 'should check if the page is hidden', ->
+      it 'checks if the page is hidden', ->
         Visibility._chechedPrefix = 'webkit'
         document.webkitHidden     = true
         Visibility.hidden().should.be.true

        callback.should.not.have.been.called
        Visibility._setListener.should.not.have.been.called

      it 'should call callback on visibility state changes', ->
        Visibility._chechedPrefix = 'webkit'
        sinon.spy(Visibility, '_setListener')
        callback = sinon.spy()

      afterEach ->
        window.setInterval.restore?()

      it 'calls DOM setInterval from internal method', ->
        sinon.stub window, 'setInterval', -> 102
        callback = ->
        Visibility._originalInterval(callback, 1000).should.eql(102)
