diff -r 000000000000 -r 6474c204b198 testing/xpcshell/example/unit/test_get_file.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/testing/xpcshell/example/unit/test_get_file.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,33 @@
+/* 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/. */
+
+var subscriptLoaded = false;
+
+function run_test() {
+  var lf = do_get_file("file.txt");
+  do_check_true(lf.exists());
+  do_check_true(lf.isFile());
+  // check that allowNonexistent works
+  lf = do_get_file("file.txt.notfound", true);
+  do_check_false(lf.exists());
+  // check that we can get a file from a subdirectory
+  lf = do_get_file("subdir/file.txt");
+  do_check_true(lf.exists());
+  do_check_true(lf.isFile());
+  // and that we can get a handle to a directory itself
+  lf = do_get_file("subdir/");
+  do_check_true(lf.exists());
+  do_check_true(lf.isDirectory());
+  // check that we can go up a level
+  lf = do_get_file("..");
+  do_check_true(lf.exists());
+  lf.append("unit");
+  lf.append("file.txt");
+  do_check_true(lf.exists());
+  // check that do_get_cwd works
+  lf = do_get_cwd();
+  do_check_true(lf.exists());
+  do_check_true(lf.isDirectory());
+}