var Cc = Components.classes; var Ci = Components.interfaces; function run_test() { var f = Cc["@mozilla.org/file/directory_service;1"]. getService(Ci.nsIProperties).get("ComRegF", Ci.nsIFile); 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); }