gecko-dev/netwerk/test/unit/test_bug261425.js

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

  var newURI = ios.newURI("http://foo.com");

  var success = false;
  try {
    newURI = newURI
      .mutate()
      .setSpec("http: //foo.com")
      .finalize();
  } catch (e) {
    success = e.result == Cr.NS_ERROR_MALFORMED_URI;
  }
  if (!success) {
    do_throw(
      "We didn't throw NS_ERROR_MALFORMED_URI when a space was passed in the hostname!"
    );
  }

  success = false;
  try {
    newURI = newURI
      .mutate()
      .setHost(" foo.com")
      .finalize();
  } catch (e) {
    success = e.result == Cr.NS_ERROR_MALFORMED_URI;
  }
  if (!success) {
    do_throw(
      "We didn't throw NS_ERROR_MALFORMED_URI when a space was passed in the hostname!"
    );
  }
}