diff -r 000000000000 -r 6474c204b198 toolkit/mozapps/extensions/test/xpcshell/test_childprocess.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_childprocess.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,21 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// This verifies that the AddonManager refuses to load in child processes.
+
+function run_test() {
+  // Already loaded the module by head_addons.js. Need to unload this again, so
+  // that overriding the app-info and re-importing the module works.
+  Components.utils.unload("resource://gre/modules/AddonManager.jsm");
+  createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "1.9.2");
+  gAppInfo.processType = AM_Ci.nsIXULRuntime.PROCESS_TYPE_CONTENT;
+  try {
+    Components.utils.import("resource://gre/modules/AddonManager.jsm");
+    do_throw("AddonManager should have refused to load");
+  }
+  catch (ex) {
+    do_print(ex.message);
+    do_check_true(!!ex.message);
+  }
+}