diff -r 000000000000 -r 6474c204b198 xpcom/tests/unit/head_xpcom.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/tests/unit/head_xpcom.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,25 @@
+var isWindows = ("@mozilla.org/windows-registry-key;1" in Components.classes);
+
+function get_test_program(prog)
+{
+  var progPath = do_get_cwd();
+  progPath.append(prog);
+  if (isWindows)
+    progPath.leafName = progPath.leafName + ".exe";
+  return progPath;
+}
+
+function set_process_running_environment()
+{
+  var envSvc = Components.classes["@mozilla.org/process/environment;1"].
+    getService(Components.interfaces.nsIEnvironment);
+  var dirSvc = Components.classes["@mozilla.org/file/directory_service;1"].
+    getService(Components.interfaces.nsIProperties);
+  var greDir = dirSvc.get("GreD", Components.interfaces.nsIFile);
+
+  envSvc.set("DYLD_LIBRARY_PATH", greDir.path);
+  // For Linux
+  envSvc.set("LD_LIBRARY_PATH", greDir.path);
+  //XXX: handle windows
+}
+