diff -r 000000000000 -r 6474c204b198 docshell/test/unit/test_pb_notification.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/docshell/test/unit/test_pb_notification.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+if (typeof Cc === "undefined")
+  Cc = Components.classes;
+if (typeof Ci === "undefined")
+  Ci = Components.interfaces;
+
+function destroy_transient_docshell() {
+  var docshell = Cc["@mozilla.org/docshell;1"].createInstance(Ci.nsIDocShell);
+  docshell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing = true;
+  do_test_pending();
+  do_timeout(0, Components.utils.forceGC);
+}
+
+function run_test() {
+  var obs = {
+    observe: function(aSubject, aTopic, aData) {
+      do_check_eq(aTopic, "last-pb-context-exited");
+      do_test_finished();
+    }
+  };
+  var os = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
+  os.addObserver(obs, "last-pb-context-exited", false);
+  destroy_transient_docshell();
+}
\ No newline at end of file