diff -r 000000000000 -r 6474c204b198 xpcom/tests/unit/test_file_equality.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/tests/unit/test_file_equality.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* 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/. */
+
+const Cr = Components.results;
+const Ci = Components.interfaces;
+
+const CC = Components.Constructor;
+var LocalFile = CC("@mozilla.org/file/local;1", "nsILocalFile", "initWithPath");
+
+function run_test()
+{
+  test_normalized_vs_non_normalized();
+}
+
+function test_normalized_vs_non_normalized()
+{
+  // get a directory that exists on all platforms
+  var dirProvider = Components.classes["@mozilla.org/file/directory_service;1"].getService(Ci.nsIProperties);
+  var tmp1 = dirProvider.get("TmpD", Ci.nsILocalFile);
+  var exists = tmp1.exists();
+  do_check_true(exists);
+  if (!exists)
+    return;
+
+  // this has the same exact path as tmp1, it should equal tmp1
+  var tmp2 = new LocalFile(tmp1.path);
+  do_check_true(tmp1.equals(tmp2));
+
+  // this is a non-normalized version of tmp1, it should not equal tmp1
+  tmp2.appendRelativePath(".");
+  do_check_false(tmp1.equals(tmp2));
+
+  // normalize and make sure they are equivalent again
+  tmp2.normalize();
+  do_check_true(tmp1.equals(tmp2));
+}