function run_test() {
  const ios = Cc["@mozilla.org/network/io-service;1"].
    getService(Ci.nsIIOService);

  var uri = ios.newURI("http://foo.com/file.txt");
  uri = uri.mutate().setPort(90).finalize();
  Assert.equal(uri.hostPort, "foo.com:90");

  uri = ios.newURI("http://foo.com:10/file.txt");
  uri = uri.mutate().setPort(500).finalize();
  Assert.equal(uri.hostPort, "foo.com:500");

  uri = ios.newURI("http://foo.com:5000/file.txt");
  uri = uri.mutate().setPort(20).finalize();
  Assert.equal(uri.hostPort, "foo.com:20");

  uri = ios.newURI("http://foo.com:5000/file.txt");
  uri = uri.mutate().setPort(-1).finalize();
  Assert.equal(uri.hostPort, "foo.com");

  uri = ios.newURI("http://foo.com:5000/file.txt");
  uri = uri.mutate().setPort(80).finalize();
  Assert.equal(uri.hostPort, "foo.com");
}