diff -r 000000000000 -r 6474c204b198 testing/mochitest/tests/browser/browser_zz_fail_openwindow.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/mochitest/tests/browser/browser_zz_fail_openwindow.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+function test() {
+  waitForExplicitFinish();
+  function done() {
+    ok(true, "timeout ran");
+    finish();
+  }
+
+  ok(OpenBrowserWindow(), "opened browser window");
+  // and didn't close it!
+
+  setTimeout(done, 10000);
+}