diff -r 000000000000 -r 6474c204b198 addon-sdk/source/test/fixtures/test-iframe.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/test/fixtures/test-iframe.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+
+var count = 0;
+
+setTimeout(function() {
+  window.addEventListener("message", function(msg) {
+    if (++count > 1) {
+    	self.postMessage(msg.data);
+    }
+    else msg.source.postMessage(msg.data, '*');
+  });
+
+  document.getElementById('inner').src = iframePath;
+}, 0);