diff -r 000000000000 -r 6474c204b198 content/base/test/chrome/cpows_child.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/base/test/chrome/cpows_child.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,108 @@
+dump('loaded child cpow test\n');
+
+content.document.title = "Hello, Kitty";
+
+(function start() {
+    sync_test();
+    async_test();
+    rpc_test();
+    nested_sync_test();
+    // The sync-ness of this call is important, because otherwise
+    // we tear down the child's document while we are
+    // still in the async test in the parent.
+    sendSyncMessage("cpows:done", {});
+  }
+)();
+
+function ok(condition, message) {
+  dump('condition: ' + condition  + ', ' + message + '\n');
+  if (!condition) {
+    sendAsyncMessage("cpows:fail", { message: message });
+    throw 'failed check: ' + message;
+  }
+}
+
+var sync_obj;
+var async_obj;
+
+function make_object()
+{
+  let o = { };
+  o.i = 5;
+  o.b = true;
+  o.s = "hello";
+  o.x = { i: 10 };
+  o.f = function () { return 99; };
+
+  // Doing anything with this Proxy will throw.
+  var throwing = new Proxy({}, new Proxy({}, {
+      get: function (trap) { throw trap; }
+    }));
+
+  let array = [1, 2, 3];
+
+  let for_json = { "n": 3, "a": array, "s": "hello", o: { "x": 10 } };
+
+  return { "data": o,
+           "throwing": throwing,
+           "document": content.document,
+           "array": array,
+           "for_json": for_json
+         };
+}
+
+function make_json()
+{
+  return { check: "ok" };
+}
+
+function sync_test()
+{
+  dump('beginning cpow sync test\n');
+  sync_obj = make_object();
+  sendSyncMessage("cpows:sync",
+    make_json(),
+    make_object());
+}
+
+function async_test()
+{
+  dump('beginning cpow async test\n');
+  async_obj = make_object();
+  sendAsyncMessage("cpows:async",
+    make_json(),
+    async_obj);
+}
+
+function rpc_test()
+{
+  dump('beginning cpow rpc test\n');
+  rpc_obj = make_object();
+  rpc_obj.data.reenter = function  () {
+    sendRpcMessage("cpows:reenter", { }, { data: { valid: true } });
+    return "ok";
+  }
+  sendRpcMessage("cpows:rpc",
+    make_json(),
+    rpc_obj);
+}
+
+function nested_sync_test()
+{
+  dump('beginning cpow nested sync test\n');
+  sync_obj = make_object();
+  sync_obj.data.reenter = function () {
+    let caught = false;
+    try {
+       sendSyncMessage("cpows:reenter_sync", { }, { });
+    } catch (e) {
+      caught = true;
+    }
+    if (!ok(caught, "should not allow nested sync"))
+      return "fail";
+    return "ok";
+  }
+  sendSyncMessage("cpows:nested_sync",
+    make_json(),
+    rpc_obj);
+}