const Ci = Components.interfaces; const Cc = Components.classes; function isParentProcess() { let appInfo = Cc["@mozilla.org/xre/app-info;1"]; return (!appInfo || appInfo.getService(Ci.nsIXULRuntime).processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT); } function run_test() { if (isParentProcess() == false) { var pb = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch); pb.setBoolPref("Test.IPC.bool", true); pb.setIntPref("Test.IPC.int", 23); pb.setCharPref("Test.IPC.char", "hey"); run_test_in_child("test_existing_prefs.JS"); } }