){
        var target = document.getElementById("gapEmTwo");
        assert_equals(getComputedStyle(target).rowGap, "20px");
        assert_equals(getComputedStyle(target).columnGap, "40px");
      }, "gap accepts em 2");
    test(
      function(){
        var target = document.getElementById("gapVw");
        // The gap size would depend on the viewport width, so to make the test pass
        // in any window size we just check it's not "normal".
        assert_not_equals(getComputedStyle(target).rowGap, 