test_nsIMutableArray.js

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

var MutableArray = CC("@mozilla.org/array;1", "nsIMutableArray");

var SupportsString = CC("@mozilla.org/supports-string;1", "nsISupportsString");

function create_n_element_array(n) {

  var arr = new MutableArray();

  for (let i = 0; i < n; i++) {

    let str = new SupportsString();

    str.data = "element " + i;

    arr.appendElement(str);

  return arr;

function test_appending_null_actually_inserts() {

  var arr = new MutableArray();

  Assert.equal(0, arr.length);

  arr.appendElement(null);

  Assert.equal(1, arr.length);

function test_object_gets_appended() {

  var arr = new MutableArray();

  var str = new SupportsString();

  str.data = "hello";

  arr.appendElement(str);

  Assert.equal(1, arr.length);

  var obj = arr.queryElementAt(0, Ci.nsISupportsString);

  Assert.equal(str, obj);

function test_insert_at_beginning() {

  var arr = create_n_element_array(5);

  // just a sanity check

  Assert.equal(5, arr.length);

  var str = new SupportsString();

  str.data = "hello";

  arr.insertElementAt(str, 0);

  Assert.equal(6, arr.length);

  var obj = arr.queryElementAt(0, Ci.nsISupportsString);

  Assert.equal(str, obj);

  // check the data of all the other objects

  for (let i = 1; i < arr.length; i++) {

    let obj2 = arr.queryElementAt(i, Ci.nsISupportsString);

    Assert.equal("element " + (i - 1), obj2.data);

function test_replace_element() {

  var arr = create_n_element_array(5);

  // just a sanity check

  Assert.equal(5, arr.length);

  var str = new SupportsString();

  str.data = "hello";

  // replace first element

  arr.replaceElementAt(str, 0);

  Assert.equal(5, arr.length);

  var obj = arr.queryElementAt(0, Ci.nsISupportsString);

  Assert.equal(str, obj);

  // replace last element

  arr.replaceElementAt(str, arr.length - 1);

  Assert.equal(5, arr.length);

  obj = arr.queryElementAt(arr.length - 1, Ci.nsISupportsString);

  Assert.equal(str, obj);

  // replace after last element, should insert empty elements

  arr.replaceElementAt(str, 9);

  Assert.equal(10, arr.length);

  obj = arr.queryElementAt(9, Ci.nsISupportsString);

  Assert.equal(str, obj);

  // AFAIK there's no way to check the empty elements, since you can't QI them.

function test_clear() {

  var arr = create_n_element_array(5);

  // just a sanity check

  Assert.equal(5, arr.length);

  arr.clear();

  Assert.equal(0, arr.length);

function test_enumerate() {

  var arr = create_n_element_array(5);

  Assert.equal(5, arr.length);

  var i = 0;

  for (let str of arr.enumerate()) {

    Assert.ok(str instanceof Ci.nsISupportsString);

    Assert.equal(str.data, "element " + i);

    i++;

  Assert.equal(arr.length, i);

function test_nsiarrayextensions() {

  // Tests to check that the extensions that make an nsArray act like an

  // nsISupportsArray for iteration purposes works.

  // Note: we do not want to QI here, just want to make sure the magic glue

  // works as a drop-in replacement.

  let fake_nsisupports_array = create_n_element_array(5);

  // Check that |Count| works.

  Assert.equal(5, fake_nsisupports_array.Count());

  for (let i = 0; i < fake_nsisupports_array.Count(); i++) {

    // Check that the generic |GetElementAt| works.

    let elm = fake_nsisupports_array.GetElementAt(i);

    Assert.notEqual(elm, null);

    let str = elm.QueryInterface(Ci.nsISupportsString);

    Assert.notEqual(str, null);

    Assert.equal(str.data, "element " + i);

var tests = [

  test_appending_null_actually_inserts,

  test_object_gets_appended,

  test_insert_at_beginning,

  test_replace_element,

  test_clear,

  test_enumerate,

  test_nsiarrayextensions,

];

function run_test() {

  for (var i = 0; i < tests.length; i++) {

    tests[i]();