gecko-dev/dom/base/test/unit/test_error_codes.js

/* 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 gExpectedStatus = null;
var gNextTestFunc = null;

var prefs = Services.prefs;

var asyncXHR = {
  load() {
    var request = new XMLHttpRequest();
    request.open("GET", "http://localhost:4444/test_error_code.xml", true);

    var self = this;
    request.addEventListener("error", function(event) {
      self.onError(event);
    });
    request.send(null);
  },
  onError: function doAsyncRequest_onError(event) {
    var request = event.target.channel.QueryInterface(Ci.nsIRequest);
    Assert.equal(request.status, gExpectedStatus);
    gNextTestFunc();
  },
};

function run_test() {
  do_test_pending();
  do_timeout(0, run_test_pt1);
}

// network offline
function run_test_pt1() {
  try {
    Services.io.manageOfflineStatus = false;
  } catch (e) {}
  Services.io.offline = true;
  prefs.setBoolPref("network.dns.offline-localhost", false);

  gExpectedStatus = Cr.NS_ERROR_OFFLINE;
  gNextTestFunc = run_test_pt2;
  dump("Testing error returned by async XHR when the network is offline\n");
  asyncXHR.load();
}

// connection refused
function run_test_pt2() {
  Services.io.offline = false;
  prefs.clearUserPref("network.dns.offline-localhost");

  gExpectedStatus = Cr.NS_ERROR_CONNECTION_REFUSED;
  gNextTestFunc = end_test;
  dump("Testing error returned by aync XHR when the connection is refused\n");
  asyncXHR.load();
}

function end_test() {
  do_test_finished();
}