diff -r 000000000000 -r 6474c204b198 browser/devtools/framework/test/browser_toolbox_custom_host.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/framework/test/browser_toolbox_custom_host.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,60 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  Cu.import("resource://gre/modules/Services.jsm");
+  let temp = {}
+  Cu.import("resource:///modules/devtools/gDevTools.jsm", temp);
+  let DevTools = temp.DevTools;
+  Cu.import("resource://gre/modules/devtools/LayoutHelpers.jsm", temp);
+  let LayoutHelpers = temp.LayoutHelpers;
+
+  Cu.import("resource://gre/modules/devtools/Loader.jsm", temp);
+  let devtools = temp.devtools;
+
+  let Toolbox = devtools.Toolbox;
+
+  let toolbox, iframe, target, tab;
+
+  waitForExplicitFinish();
+
+  gBrowser.selectedTab = gBrowser.addTab();
+  target = TargetFactory.forTab(gBrowser.selectedTab);
+
+  window.addEventListener("message", onMessage);
+
+  iframe = document.createElement("iframe");
+  document.documentElement.appendChild(iframe);
+
+  gBrowser.selectedBrowser.addEventListener("load", function onLoad(evt) {
+    gBrowser.selectedBrowser.removeEventListener(evt.type, onLoad, true);
+    let options = {customIframe: iframe};
+    gDevTools.showToolbox(target, null, Toolbox.HostType.CUSTOM, options)
+             .then(testCustomHost, console.error)
+             .then(null, console.error);
+  }, true);
+
+  content.location = "data:text/html,test custom host";
+
+  function onMessage(event) {
+    info("onMessage: " + event.data);
+    let json = JSON.parse(event.data);
+    if (json.name == "toolbox-close") {
+      ok("Got the `toolbox-close` message");
+      cleanup();
+    }
+  }
+
+  function testCustomHost(toolbox) {
+    is(toolbox.doc.defaultView.top, window, "Toolbox is included in browser.xul");
+    is(toolbox.doc, iframe.contentDocument, "Toolbox is in the custom iframe");
+    executeSoon(() => gBrowser.removeCurrentTab());
+  }
+
+  function cleanup() {
+    window.removeEventListener("message", onMessage);
+    iframe.remove();
+    finish();
+  }
+}