The Tor Browser / file revision

 const Cc = Components.classes;

 const Ci = Components.interfaces;

 function run_test() {

   // skip this test on Windows

   var isWindows = ("@mozilla.org/windows-registry-key;1" in Components.classes);

   if (!isWindows) {

     var testDir = __LOCATION__.parent;

     // create a test file, then symlink it, then check that we think it's a symlink

     var targetFile = testDir.clone();

     targetFile.append("target.txt");

     if (!targetFile.exists())

       targetFile.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0644);

     var link = testDir.clone();

     link.append("link");

     if (link.exists())

       link.remove(false);

     var ln = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsILocalFile);

     ln.initWithPath("/bin/ln");

     var process = Cc["@mozilla.org/process/util;1"].createInstance(Ci.nsIProcess);

     process.init(ln);

     var args = ["-s", targetFile.path, link.path];

     process.run(true, args, args.length);

     do_check_true(link.isSymlink());

   }

 }