chrome/test/data/extensions/api_test/debugger_file_access/background.js

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

function openTab(url) {
  return new Promise((resolve) => {
    chrome.tabs.onUpdated.addListener(
        function listener(tabId, changeInfo, tab) {
      // Note: Use new URL(...).href to compare in order to normalize the URL,
      // which is important if the path referenced a parent (as happens in the
      // file urls).
      if (changeInfo.status !== 'complete' ||
          (new URL(tab.url)).href !== (new URL(url)).href) {
        return;
      }
      chrome.tabs.onUpdated.removeListener(listener);
      resolve(tab.id);
    });
    chrome.tabs.create({url: url});
  });
}

chrome.test.getConfig((config) => {
  const fileUrl = config.testDataDirectory + '/../body1.html';
  const expectFileAccess = !!config.customArg;

  console.log(fileUrl);

  chrome.test.runTests([
    function verifyInitialState() {
      if (config.customArg)
        chrome.test.assertEq('enabled', config.customArg);
      chrome.extension.isAllowedFileSchemeAccess((allowed) => {
        chrome.test.assertEq(expectFileAccess, allowed);
        chrome.test.succeed();
      });
    },

    function testAttach() {
      openTab(fileUrl).then((tabId) => {
        chrome.debugger.attach({tabId: tabId}, '1.1', function() {
          if (expectFileAccess) {
            chrome.test.assertNoLastError();
            chrome.debugger.detach({tabId: tabId}, function() {
              chrome.test.assertNoLastError();
              chrome.test.succeed();
            });
          } else {
            chrome.test.assertLastError('Cannot attach to this target.');
            chrome.test.succeed();
          }
        });
      });
    },

    function testAttachAndNavigate() {
      openTab(chrome.runtime.getURL('dummy.html')).then((tabId) => {
        chrome.debugger.attach({tabId: tabId}, '1.1', function() {
          chrome.test.assertNoLastError();
          let responded = false;

          function onResponse() {
            responded = true;
            if (expectFileAccess) {
              chrome.test.assertNoLastError();
              chrome.tabs.remove(tabId);
            } else {
              chrome.test.assertLastError('Detached while handling command.');
            }
          }

          function onDetach(from, reason) {
            console.warn('Detached');
            chrome.debugger.onDetach.removeListener(onDetach);
            chrome.test.assertTrue(responded);
            chrome.test.assertEq(tabId, from.tabId);
            chrome.test.assertEq('target_closed', reason);
            chrome.test.succeed();
          }

          chrome.debugger.onDetach.addListener(onDetach);
          chrome.debugger.sendCommand({tabId: tabId}, 'Page.navigate',
                                      {url: fileUrl}, onResponse);
        });
      });
    },
  ]);
});