diff -r 000000000000 -r 6474c204b198 addon-sdk/source/test/test-test-utils.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/test/test-test-utils.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* 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'
+
+const { setTimeout } = require('sdk/timers');
+const { waitUntil } = require('sdk/test/utils');
+
+exports.testWaitUntil = function (assert, done) {
+  let bool = false;
+  let finished = false;
+  waitUntil(() => {
+    if (finished)
+      assert.fail('interval should be cleared after predicate is truthy');
+    return bool;
+  }).then(function () {
+    assert.ok(bool,
+      'waitUntil shouldn\'t call until predicate is truthy');
+    finished = true;
+    done();
+  });
+  setTimeout(() => { bool = true; }, 20);
+};
+
+exports.testWaitUntilInterval = function (assert, done) {
+  let bool = false;
+  let finished = false;
+  let counter = 0;
+  waitUntil(() => {
+    if (finished)
+      assert.fail('interval should be cleared after predicate is truthy');
+    counter++;
+    return bool;
+  }, 50).then(function () {
+    assert.ok(bool,
+      'waitUntil shouldn\'t call until predicate is truthy');
+    assert.equal(counter, 1,
+      'predicate should only be called once with a higher interval');
+    finished = true;
+    done();
+  });
+  setTimeout(() => { bool = true; }, 10);
+};
+
+require('sdk/test').run(exports);