(function(env) {
  function hasFunctioningSets() {
    if (typeof Set === 'undefined') { return false; }

    try {
      var s = new Set();
      s.add(1);
      s.add(2);

      if (s.size !== 2) { return false; }
      if (s.has(1) !== true) { return false; }

      var iterations = 0;
      var isForEachWorking = true;
      s.forEach(function(value, key, set) {
        isForEachWorking = isForEachWorking && set === s;

        if (iterations===0) {
          isForEachWorking = isForEachWorking && (key===value) && value===1;
        } else if (iterations===1) {
          isForEachWorking = isForEachWorking && (key===value) && value===2;
        }

        iterations++;
      });
      if (iterations !== 2) { return false; }
      if (isForEachWorking !== true) { return false; }

      return true;
    } catch(e) {
      return false;
    }
  }

  env.requireFunctioningSets = function() {
    if (!hasFunctioningSets()) {
      env.pending("Browser has incomplete or missing support for Sets");
    }
  };

})(jasmine.getEnv());