diff -r 000000000000 -r 6474c204b198 browser/metro/base/tests/mochitest/browser_ui_telemetry.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/metro/base/tests/mochitest/browser_ui_telemetry.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,66 @@
+// -*- Mode: js2; tab-width: 2; indent-tabs-mode: nil; js2-basic-offset: 2; js2-skip-preprocessor-directives: t; -*-
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+function test() {
+  runTests();
+}
+
+function getTelemetryPayload() {
+  return Cu.import("resource://gre/modules/TelemetryPing.jsm", {}).
+    TelemetryPing.getPayload();
+}
+
+gTests.push({
+  desc: "Test browser-ui telemetry",
+  run: function testBrowserUITelemetry() {
+    // startup should have registered simple measures function
+    is(getTelemetryPayload().info.appName, "MetroFirefox");
+
+    let simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    ok(simpleMeasurements, "simpleMeasurements are truthy");
+    ok(simpleMeasurements.UITelemetry["metro-ui"]["window-width"], "window-width measurement was captured");
+    ok(simpleMeasurements.UITelemetry["metro-ui"]["window-height"], "window-height measurement was captured");
+  }
+});
+
+gTests.push({
+  desc: "Test tab count telemetry",
+  run: function() {
+    // Wait for Session Manager to be initialized.
+    yield waitForCondition(() => window.__SSID);
+
+    Services.obs.notifyObservers(null, "reset-telemetry-vars", null);
+    yield waitForCondition(function () {
+      let simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+      return simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"] == 1;
+    });
+
+    let simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"], 1);
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["maxTabCount"], 1);
+
+    let tab2 = Browser.addTab("about:mozilla");
+    simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"], 2);
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["maxTabCount"], 2);
+
+    let tab3 = Browser.addTab("about:config");
+    simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"], 3);
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["maxTabCount"], 3);
+
+    Browser.closeTab(tab2, { forceClose: true } );
+    simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"], 2);
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["maxTabCount"], 3);
+
+    Browser.closeTab(tab3, { forceClose: true } );
+    simpleMeasurements = getTelemetryPayload().simpleMeasurements;
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["currTabCount"], 1);
+    is(simpleMeasurements.UITelemetry["metro-tabs"]["maxTabCount"], 3);
+  }
+});
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