The Tor Browser / file revision

 // Should report file not found on non-existent files

 const Cc = Components.classes;

 const Ci = Components.interfaces;

 const path = "data/test_bug333423.zip";

 function run_test() {

   var ios = Cc["@mozilla.org/network/io-service;1"].

             getService(Ci.nsIIOService);

   var spec = "jar:" + ios.newFileURI(do_get_file(path)).spec + "!/";

   var channel = ios.newChannel(spec + "file_that_isnt_in.archive", null, null);

   try {

     instr = channel.open();

     do_throw("Failed to report that file doesn't exist")

   } catch (e) {

       do_check_true(e.name == "NS_ERROR_FILE_NOT_FOUND")

   }

 }