JSTests/test262/test/built-ins/Set/set-iterator-close-after-add-failure.js

// Copyright (C) 2015 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
es6id: 23.2.1.1
description: >
    Set ( [ iterable ] )

    When the Set function is called with optional argument iterable the following steps are taken:

    ...
    9. Repeat
      a. Let next be IteratorStep(iter).
      b. ReturnIfAbrupt(next).
      c. If next is false, return set.
      d. Let nextValue be IteratorValue(next).
      e. ReturnIfAbrupt(nextValue).
      f. Let status be Call(adder, set, «nextValue.[[value]]»).
      g. If status is an abrupt completion, return IteratorClose(iter, status).

---*/

var count = 0;
var iterable = {};
iterable[Symbol.iterator] = function() {
  return {
    next: function() {
      return { value: null, done: false };
    },
    return: function() {
      count += 1;
    }
  };
};
Set.prototype.add = function() { throw new Error(); }

assert.throws(Error, function() {
  new Set(iterable);
});

assert.sameValue(
  count, 1, "The iterator is closed when `Set.prototype.add` throws an error."
);