diff -r 000000000000 -r 6474c204b198 services/common/tests/unit/test_utils_deepCopy.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/common/tests/unit/test_utils_deepCopy.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+Cu.import("resource://testing-common/services-common/utils.js");
+
+function run_test() {
+  let thing = {o: {foo: "foo", bar: ["bar"]}, a: ["foo", {bar: "bar"}]};
+  let ret = TestingUtils.deepCopy(thing);
+  do_check_neq(ret, thing)
+  do_check_neq(ret.o, thing.o);
+  do_check_neq(ret.o.bar, thing.o.bar);
+  do_check_neq(ret.a, thing.a);
+  do_check_neq(ret.a[1], thing.a[1]);
+  do_check_eq(ret.o.foo, thing.o.foo);
+  do_check_eq(ret.o.bar[0], thing.o.bar[0]);
+  do_check_eq(ret.a[0], thing.a[0]);
+  do_check_eq(ret.a[1].bar, thing.a[1].bar);
+}