diff -r 000000000000 -r 6474c204b198 toolkit/webapps/tests/head.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/webapps/tests/head.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,79 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+
+Cu.import("resource://gre/modules/osfile.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://gre/modules/Promise.jsm");
+
+const LINUX = navigator.platform.startsWith("Linux");
+const MAC = navigator.platform.startsWith("Mac");
+const WIN = navigator.platform.startsWith("Win");
+const MAC_106 = navigator.userAgent.contains("Mac OS X 10.6");
+
+function checkFiles(files) {
+  return Task.spawn(function*() {
+    for (let file of files) {
+      if (!(yield OS.File.exists(file))) {
+        info("File doesn't exist: " + file);
+        return false;
+      }
+    }
+
+    return true;
+  });
+}
+
+function checkDateHigherThan(files, date) {
+  return Task.spawn(function*() {
+    for (let file of files) {
+      if (!(yield OS.File.exists(file))) {
+        info("File doesn't exist: " + file);
+        return false;
+      }
+
+      let stat = yield OS.File.stat(file);
+      if (!(stat.lastModificationDate > date)) {
+        info("File not newer: " + file);
+        return false;
+      }
+    }
+
+    return true;
+  });
+}
+
+function wait(time) {
+  let deferred = Promise.defer();
+
+  setTimeout(function() {
+    deferred.resolve();
+  }, time);
+
+  return deferred.promise;
+}
+
+// Helper to create a nsIFile from a set of path components
+function getFile() {
+  let file = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+  file.initWithPath(OS.Path.join.apply(OS.Path, arguments));
+  return file;
+}
+
+function setDryRunPref() {
+  let old_dry_run;
+  try {
+    old_dry_run = Services.prefs.getBoolPref("browser.mozApps.installer.dry_run");
+  } catch (ex) {}
+
+  Services.prefs.setBoolPref("browser.mozApps.installer.dry_run", false);
+
+  SimpleTest.registerCleanupFunction(function() {
+    if (old_dry_run === undefined) {
+      Services.prefs.clearUserPref("browser.mozApps.installer.dry_run");
+    } else {
+      Services.prefs.setBoolPref("browser.mozApps.installer.dry_run", old_dry_run);
+    }
+  });
+}