stContents = '';
writingModes.forEach(function(writingMode) {
    testContents += "<div class='test-row'>";
    flexDirections.forEach(function(flexDirection) {
        var containerClass = 'container ' + writingMode;
        var flexboxClass = 'flexbox ' + flexDirection;
        testContents +=
            "<div class='" + containerClass + "'>" +
            "<div class='" + flexboxClass + "'>" +
            "<div></div>" +
            "</div>" +
            "</div>";
    });
    testContents += "</div>";
