id");
    test(
      function(){
        var target = document.getElementById("invalidColumnGapMultiple");
        assert_equals(getComputedStyle(target).columnGap, "normal");
      }, "column-gap with multiple values is invalid");
    test(
      function(){
        var target = document.getElementById("invalidColumnGapAngle");
        assert_equals(getComputedStyle(target).columnGap, "normal");
      }, "Angle column-gap is invalid");
    test(
      function(){
        var target = document.getElementBy