fune/testing/mochitest/chrome/test_chromeGetTestFile.xhtml

<?xml version="1.0"?>
<!-- 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/. -->
<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
                 type="text/css"?>
<window title="Test chrome harness functions"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
  <script src="chrome://mochikit/content/chrome-harness.js"></script>
  <script type="application/javascript">
  <![CDATA[
    let {Promise} = ChromeUtils.import("resource://gre/modules/Promise.jsm");
    const {OS} = ChromeUtils.import("resource://gre/modules/osfile.jsm");
    let decoder = new TextDecoder();

    SimpleTest.waitForExplicitFinish();

    SimpleTest.doesThrow(function () {
      getTestFilePath("/test_chromeGetTestFile.xhtml")
    }, "getTestFilePath rejects absolute paths");

    Promise.all([
      OS.File.exists(getTestFilePath("test_chromeGetTestFile.xhtml"))
        .then(function (exists) {
          ok(exists, "getTestFilePath consider the path as being relative");
        }),

      OS.File.exists(getTestFilePath("./test_chromeGetTestFile.xhtml"))
        .then(function (exists) {
          ok(exists, "getTestFilePath also accepts explicit relative path");
        }),

      OS.File.exists(getTestFilePath("./test_chromeGetTestFileTypo.xhtml"))
        .then(function (exists) {
          ok(!exists, "getTestFilePath do not throw if the file doesn't exists");
        }),

      OS.File.read(getTestFilePath("test-dir/test-file"))
        .then(function (array) {
          is(decoder.decode(array), "foo\n", "getTestFilePath can reach sub-folder files 1/2");
        }),

      OS.File.read(getTestFilePath("./test-dir/test-file"))
        .then(function (array) {
          is(decoder.decode(array), "foo\n", "getTestFilePath can reach sub-folder files 2/2");
        })

    ]).then(function () {
      SimpleTest.finish();
    }, console.error);
  ]]>
  </script>
</window>