function hideSuitesWithout(classname) {
  var suites = document.getElementsByClassName('suite');
  for (var i = 0; i < suites.length; i++) {
    var els = suites[i].getElementsByClassName(classname);
    if (0 == els.length) suites[i].className += ' hidden';
  }
}
Check for suites that do not have elements
with `classname`, and hide them.