diff -r 000000000000 -r 6474c204b198 browser/devtools/tilt/test/browser_tilt_arcball-reset.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/tilt/test/browser_tilt_arcball-reset.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,129 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+let tiltOpened = false;
+
+function test() {
+  if (!isTiltEnabled()) {
+    info("Skipping part of the arcball test because Tilt isn't enabled.");
+    return;
+  }
+  if (!isWebGLSupported()) {
+    info("Skipping part of the arcball test because WebGL isn't supported.");
+    return;
+  }
+
+  requestLongerTimeout(10);
+  waitForExplicitFinish();
+
+  createTab(function() {
+    createTilt({
+      onTiltOpen: function(instance)
+      {
+        tiltOpened = true;
+
+        performTest(instance.presenter.canvas,
+                    instance.controller.arcball, function() {
+
+          info("Killing arcball reset test.");
+
+          Services.obs.addObserver(cleanup, DESTROYED, false);
+          Tilt.destroy(Tilt.currentWindowId);
+        });
+      }
+    }, false, function suddenDeath()
+    {
+      info("Tilt could not be initialized properly.");
+      cleanup();
+    });
+  });
+}
+
+function performTest(canvas, arcball, callback) {
+  is(document.activeElement, canvas,
+    "The visualizer canvas should be focused when performing this test.");
+
+
+  info("Starting arcball reset test.");
+
+  // start translating and rotating sometime at random
+
+  window.setTimeout(function() {
+    info("Synthesizing key down events.");
+
+    EventUtils.synthesizeKey("VK_W", { type: "keydown" });
+    EventUtils.synthesizeKey("VK_LEFT", { type: "keydown" });
+
+    // wait for some arcball translations and rotations to happen
+
+    window.setTimeout(function() {
+      info("Synthesizing key up events.");
+
+      EventUtils.synthesizeKey("VK_W", { type: "keyup" });
+      EventUtils.synthesizeKey("VK_LEFT", { type: "keyup" });
+
+      // ok, transformations finished, we can now try to reset the model view
+
+      window.setTimeout(function() {
+        info("Synthesizing arcball reset key press.");
+
+        arcball._onResetStart = function() {
+          info("Starting arcball reset animation.");
+        };
+
+        arcball._onResetStep = function() {
+          info("\nlastRot: " + quat4.str(arcball._lastRot) +
+               "\ndeltaRot: " + quat4.str(arcball._deltaRot) +
+               "\ncurrentRot: " + quat4.str(arcball._currentRot) +
+               "\nlastTrans: " + vec3.str(arcball._lastTrans) +
+               "\ndeltaTrans: " + vec3.str(arcball._deltaTrans) +
+               "\ncurrentTrans: " + vec3.str(arcball._currentTrans) +
+               "\nadditionalRot: " + vec3.str(arcball._additionalRot) +
+               "\nadditionalTrans: " + vec3.str(arcball._additionalTrans) +
+               "\nzoomAmount: " + arcball._zoomAmount);
+        };
+
+        arcball._onResetFinish = function() {
+          ok(isApproxVec(arcball._lastRot, [0, 0, 0, 1]),
+            "The arcball _lastRot field wasn't reset correctly.");
+          ok(isApproxVec(arcball._deltaRot, [0, 0, 0, 1]),
+            "The arcball _deltaRot field wasn't reset correctly.");
+          ok(isApproxVec(arcball._currentRot, [0, 0, 0, 1]),
+            "The arcball _currentRot field wasn't reset correctly.");
+
+          ok(isApproxVec(arcball._lastTrans, [0, 0, 0]),
+            "The arcball _lastTrans field wasn't reset correctly.");
+          ok(isApproxVec(arcball._deltaTrans, [0, 0, 0]),
+            "The arcball _deltaTrans field wasn't reset correctly.");
+          ok(isApproxVec(arcball._currentTrans, [0, 0, 0]),
+            "The arcball _currentTrans field wasn't reset correctly.");
+
+          ok(isApproxVec(arcball._additionalRot, [0, 0, 0]),
+            "The arcball _additionalRot field wasn't reset correctly.");
+          ok(isApproxVec(arcball._additionalTrans, [0, 0, 0]),
+            "The arcball _additionalTrans field wasn't reset correctly.");
+
+          ok(isApproxVec([arcball._zoomAmount], [0]),
+            "The arcball _zoomAmount field wasn't reset correctly.");
+
+          executeSoon(function() {
+            info("Finishing arcball reset test.");
+            callback();
+          });
+        };
+
+        EventUtils.synthesizeKey("VK_R", { type: "keydown" });
+
+      }, Math.random() * 1000); // leave enough time for transforms to happen
+    }, Math.random() * 1000);
+  }, Math.random() * 1000);
+}
+
+function cleanup() {
+  info("Cleaning up arcball reset test.");
+
+  if (tiltOpened) { Services.obs.removeObserver(cleanup, DESTROYED); }
+  gBrowser.removeCurrentTab();
+  finish();
+}