The Tor Browser / file revision

 var Cc = Components.classes;

 var Ci = Components.interfaces;

 function run_test() {

   var f = do_get_file('test_bug336501.js');

   var fis =

       Cc["@mozilla.org/network/file-input-stream;1"].

       createInstance(Ci.nsIFileInputStream);

   fis.init(f, -1, -1, 0); 

   var bis =

       Cc["@mozilla.org/network/buffered-input-stream;1"].

       createInstance(Ci.nsIBufferedInputStream);

   bis.init(fis, 32);

   var sis =

       Cc["@mozilla.org/scriptableinputstream;1"].

       createInstance(Ci.nsIScriptableInputStream);

   sis.init(bis);

   sis.read(45);

   sis.close();

   var data = sis.read(45);

   do_check_eq(data.length, 0);

 }