diff -r 000000000000 -r 6474c204b198 browser/devtools/tilt/test/browser_tilt_zoom.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/tilt/test/browser_tilt_zoom.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,91 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+const ZOOM = 2;
+const RESIZE = 50;
+let tiltOpened = false;
+
+function test() {
+  if (!isTiltEnabled()) {
+    info("Skipping controller test because Tilt isn't enabled.");
+    return;
+  }
+  if (!isWebGLSupported()) {
+    info("Skipping controller test because WebGL isn't supported.");
+    return;
+  }
+
+  waitForExplicitFinish();
+
+  createTab(function() {
+    TiltUtils.setDocumentZoom(window, ZOOM);
+
+    createTilt({
+      onTiltOpen: function(instance)
+      {
+        tiltOpened = true;
+
+        ok(isApprox(instance.presenter._getPageZoom(), ZOOM),
+          "The Highlighter zoom doesn't have the expected results.");
+
+        ok(isApprox(instance.presenter.transforms.zoom, ZOOM),
+          "The presenter transforms zoom wasn't initially set correctly.");
+
+        let contentWindow = gBrowser.selectedBrowser.contentWindow;
+        let initialWidth = contentWindow.innerWidth;
+        let initialHeight = contentWindow.innerHeight;
+
+        let renderer = instance.presenter._renderer;
+        let arcball = instance.controller.arcball;
+
+        ok(isApprox(contentWindow.innerWidth * ZOOM, renderer.width, 1),
+          "The renderer width wasn't set correctly before the resize.");
+        ok(isApprox(contentWindow.innerHeight * ZOOM, renderer.height, 1),
+          "The renderer height wasn't set correctly before the resize.");
+
+        ok(isApprox(contentWindow.innerWidth * ZOOM, arcball.width, 1),
+          "The arcball width wasn't set correctly before the resize.");
+        ok(isApprox(contentWindow.innerHeight * ZOOM, arcball.height, 1),
+          "The arcball height wasn't set correctly before the resize.");
+
+
+        window.resizeBy(-RESIZE * ZOOM, -RESIZE * ZOOM);
+
+        executeSoon(function() {
+          ok(isApprox(contentWindow.innerWidth + RESIZE, initialWidth, 1),
+            "The content window width wasn't set correctly after the resize.");
+          ok(isApprox(contentWindow.innerHeight + RESIZE, initialHeight, 1),
+            "The content window height wasn't set correctly after the resize.");
+
+          ok(isApprox(contentWindow.innerWidth * ZOOM, renderer.width, 1),
+            "The renderer width wasn't set correctly after the resize.");
+          ok(isApprox(contentWindow.innerHeight * ZOOM, renderer.height, 1),
+            "The renderer height wasn't set correctly after the resize.");
+
+          ok(isApprox(contentWindow.innerWidth * ZOOM, arcball.width, 1),
+            "The arcball width wasn't set correctly after the resize.");
+          ok(isApprox(contentWindow.innerHeight * ZOOM, arcball.height, 1),
+            "The arcball height wasn't set correctly after the resize.");
+
+
+          window.resizeBy(RESIZE * ZOOM, RESIZE * ZOOM);
+
+
+          Services.obs.addObserver(cleanup, DESTROYED, false);
+          Tilt.destroy(Tilt.currentWindowId);
+        });
+      }
+    }, false, function suddenDeath()
+    {
+      info("Tilt could not be initialized properly.");
+      cleanup();
+    });
+  });
+}
+
+function cleanup() {
+  if (tiltOpened) { Services.obs.removeObserver(cleanup, DESTROYED); }
+  gBrowser.removeCurrentTab();
+  finish();
+}