   run: ->
     _.each([0..(@docLength - 1)], (index) =>
       tests = {
+        "insert nothing":
+          value: ''
+          attributes: {}
         "insert A":
           value: 'A'
           attributes: {}


  run: ->
    _.each([0..(@docLength - 2)], (index) =>
      _.each([1..(@docLength-index-1)], (length) =>
        deleteDelta = Tandem.Delta.makeDeleteDelta(@docLength, index, length)
        expected = @delta.compose(deleteDelta)
        @editorTest.run("Delete #{length} characters at #{index}",


  run: ->
    _.each([0..(@docLength - 2)], (index) =>
      _.each([0..(@docLength-index-1)], (length) =>
        formats =
          color: ['red', null]
          bold: [true, false]
