electron/spec-main/extensions-spec.ts

import { expect } from 'chai';
import { app, session, BrowserWindow, ipcMain, WebContents, Extension } from 'electron';
import { closeAllWindows, closeWindow } from './window-helpers';
import * as http from 'http';
import { AddressInfo } from 'net';
import * as path from 'path';
import * as fs from 'fs';
import { ifdescribe } from './spec-helpers';
import { emittedOnce, emittedNTimes } from './events-helpers';

const fixtures = path.join(__dirname, 'fixtures');

ifdescribe(process.electronBinding('features').isExtensionsEnabled())('chrome extensions', () => {
  // NB. extensions are only allowed on http://, https:// and ftp:// (!) urls by default.
  let server: http.Server;
  let url: string;
  before(async () => {
    server = http.createServer((req, res) => res.end());
    await new Promise(resolve => server.listen(0, '127.0.0.1', () => {
      url = `http://127.0.0.1:${(server.address() as AddressInfo).port}`;
      resolve();
    }));
  });
  after(() => {
    server.close();
  });
  afterEach(closeAllWindows);
  afterEach(() => {
    session.defaultSession.getAllExtensions().forEach((e: any) => {
      session.defaultSession.removeExtension(e.id);
    });
  });

  it('loads an extension', async () => {
    // NB. we have to use a persist: session (i.e. non-OTR) because the
    // extension registry is redirected to the main session. so installing an
    // extension in an in-memory session results in it being installed in the
    // default session.
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    await customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'));
    const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
    await w.loadURL(url);
    const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
    expect(bg).to.equal('red');
  });

  it('serializes a loaded extension', async () => {
    const extensionPath = path.join(fixtures, 'extensions', 'red-bg');
    const manifest = JSON.parse(fs.readFileSync(path.join(extensionPath, 'manifest.json'), 'utf-8'));
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    const extension = await customSession.loadExtension(extensionPath);
    expect(extension.id).to.be.a('string');
    expect(extension.name).to.be.a('string');
    expect(extension.path).to.be.a('string');
    expect(extension.version).to.be.a('string');
    expect(extension.url).to.be.a('string');
    expect(extension.manifest).to.deep.equal(manifest);
  });

  it('removes an extension', async () => {
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    const { id } = await customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'));
    {
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      await w.loadURL(url);
      const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
      expect(bg).to.equal('red');
    }
    customSession.removeExtension(id);
    {
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      await w.loadURL(url);
      const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
      expect(bg).to.equal('');
    }
  });

  it('lists loaded extensions in getAllExtensions', async () => {
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    const e = await customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'));
    expect(customSession.getAllExtensions()).to.deep.equal([e]);
    customSession.removeExtension(e.id);
    expect(customSession.getAllExtensions()).to.deep.equal([]);
  });

  it('gets an extension by id', async () => {
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    const e = await customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'));
    expect(customSession.getExtension(e.id)).to.deep.equal(e);
  });

  it('confines an extension to the session it was loaded in', async () => {
    const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
    await customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'));
    const w = new BrowserWindow({ show: false }); // not in the session
    await w.loadURL(url);
    const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
    expect(bg).to.equal('');
  });

  it('loading an extension in a temporary session throws an error', async () => {
    const customSession = session.fromPartition(require('uuid').v4());
    await expect(customSession.loadExtension(path.join(fixtures, 'extensions', 'red-bg'))).to.eventually.be.rejectedWith('Extensions cannot be loaded in a temporary session');
  });

  describe('chrome.i18n', () => {
    let w: BrowserWindow;
    let extension: Extension;
    const exec = async (name: string) => {
      const p = emittedOnce(ipcMain, 'success');
      await w.webContents.executeJavaScript(`exec('${name}')`);
      const [, result] = await p;
      return result;
    };
    beforeEach(async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      extension = await customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-i18n'));
      w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      await w.loadURL(url);
    });
    it('getAcceptLanguages()', async () => {
      const result = await exec('getAcceptLanguages');
      expect(result).to.be.an('array').and.deep.equal(['en-US']);
    });
    it('getMessage()', async () => {
      const result = await exec('getMessage');
      expect(result.id).to.be.a('string').and.equal(extension.id);
      expect(result.name).to.be.a('string').and.equal('chrome-i18n');
    });
  });

  describe('chrome.runtime', () => {
    let content: any;
    before(async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-runtime'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      try {
        await w.loadURL(url);
        content = JSON.parse(await w.webContents.executeJavaScript('document.documentElement.textContent'));
        expect(content).to.be.an('object');
      } finally {
        w.destroy();
      }
    });
    it('getManifest()', () => {
      expect(content.manifest).to.be.an('object').with.property('name', 'chrome-runtime');
    });
    it('id', () => {
      expect(content.id).to.be.a('string').with.lengthOf(32);
    });
    it('getURL()', () => {
      expect(content.url).to.be.a('string').and.match(/^chrome-extension:\/\/.*main.js$/);
    });
  });

  describe('chrome.storage', () => {
    it('stores and retrieves a key', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      await customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-storage'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      try {
        const p = emittedOnce(ipcMain, 'storage-success');
        await w.loadURL(url);
        const [, v] = await p;
        expect(v).to.equal('value');
      } finally {
        w.destroy();
      }
    });
  });

  describe('chrome.tabs', () => {
    it('executeScript', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      await customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-api'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      await w.loadURL(url);

      const message = { method: 'executeScript', args: ['1 + 2'] };
      w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

      const [,, responseString] = await emittedOnce(w.webContents, 'console-message');
      const response = JSON.parse(responseString);

      expect(response).to.equal(3);
    });

    it('connect', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      await customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-api'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      await w.loadURL(url);

      const portName = require('uuid').v4();
      const message = { method: 'connectTab', args: [portName] };
      w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

      const [,, responseString] = await emittedOnce(w.webContents, 'console-message');
      const response = responseString.split(',');
      expect(response[0]).to.equal(portName);
      expect(response[1]).to.equal('howdy');
    });

    it('sendMessage receives the response', async function () {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      await customSession.loadExtension(path.join(fixtures, 'extensions', 'chrome-api'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      await w.loadURL(url);

      const message = { method: 'sendMessage', args: ['Hello World!'] };
      w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

      const [,, responseString] = await emittedOnce(w.webContents, 'console-message');
      const response = JSON.parse(responseString);

      expect(response.message).to.equal('Hello World!');
      expect(response.tabId).to.equal(w.webContents.id);
    });
  });

  describe('background pages', () => {
    it('loads a lazy background page when sending a message', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      await customSession.loadExtension(path.join(fixtures, 'extensions', 'lazy-background-page'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession, nodeIntegration: true } });
      try {
        w.loadURL(url);
        const [, resp] = await emittedOnce(ipcMain, 'bg-page-message-response');
        expect(resp.message).to.deep.equal({ some: 'message' });
        expect(resp.sender.id).to.be.a('string');
        expect(resp.sender.origin).to.equal(url);
        expect(resp.sender.url).to.equal(url + '/');
      } finally {
        w.destroy();
      }
    });

    it('can use extension.getBackgroundPage from a ui page', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      const { id } = await customSession.loadExtension(path.join(fixtures, 'extensions', 'lazy-background-page'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      await w.loadURL(`chrome-extension://${id}/page-get-background.html`);
      const receivedMessage = await w.webContents.executeJavaScript('window.completionPromise');
      expect(receivedMessage).to.deep.equal({ some: 'message' });
    });

    it('can use extension.getBackgroundPage from a ui page', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      const { id } = await customSession.loadExtension(path.join(fixtures, 'extensions', 'lazy-background-page'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      await w.loadURL(`chrome-extension://${id}/page-get-background.html`);
      const receivedMessage = await w.webContents.executeJavaScript('window.completionPromise');
      expect(receivedMessage).to.deep.equal({ some: 'message' });
    });

    it('can use runtime.getBackgroundPage from a ui page', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      const { id } = await customSession.loadExtension(path.join(fixtures, 'extensions', 'lazy-background-page'));
      const w = new BrowserWindow({ show: false, webPreferences: { session: customSession } });
      await w.loadURL(`chrome-extension://${id}/page-runtime-get-background.html`);
      const receivedMessage = await w.webContents.executeJavaScript('window.completionPromise');
      expect(receivedMessage).to.deep.equal({ some: 'message' });
    });
  });

  describe('devtools extensions', () => {
    let showPanelTimeoutId: any = null;
    afterEach(() => {
      if (showPanelTimeoutId) clearTimeout(showPanelTimeoutId);
    });
    const showLastDevToolsPanel = (w: BrowserWindow) => {
      w.webContents.once('devtools-opened', () => {
        const show = () => {
          if (w == null || w.isDestroyed()) return;
          const { devToolsWebContents } = w as unknown as { devToolsWebContents: WebContents | undefined };
          if (devToolsWebContents == null || devToolsWebContents.isDestroyed()) {
            return;
          }

          const showLastPanel = () => {
            // this is executed in the devtools context, where UI is a global
            const { UI } = (window as any);
            const lastPanelId = UI.inspectorView._tabbedPane._tabs.peekLast().id;
            UI.inspectorView.showPanel(lastPanelId);
          };
          devToolsWebContents.executeJavaScript(`(${showLastPanel})()`, false).then(() => {
            showPanelTimeoutId = setTimeout(show, 100);
          });
        };
        showPanelTimeoutId = setTimeout(show, 100);
      });
    };

    it('loads a devtools extension', async () => {
      const customSession = session.fromPartition(`persist:${require('uuid').v4()}`);
      customSession.loadExtension(path.join(fixtures, 'extensions', 'devtools-extension'));
      const w = new BrowserWindow({ show: true, webPreferences: { session: customSession, nodeIntegration: true } });
      await w.loadURL('data:text/html,hello');
      w.webContents.openDevTools();
      showLastDevToolsPanel(w);
      await emittedOnce(ipcMain, 'winning');
    });
  });

  describe('deprecation shims', () => {
    it('loads an extension through BrowserWindow.addExtension', async () => {
      BrowserWindow.addExtension(path.join(fixtures, 'extensions', 'red-bg'));
      const w = new BrowserWindow({ show: false });
      await w.loadURL(url);
      const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
      expect(bg).to.equal('red');
    });

    it('loads an extension through BrowserWindow.addDevToolsExtension', async () => {
      BrowserWindow.addDevToolsExtension(path.join(fixtures, 'extensions', 'red-bg'));
      const w = new BrowserWindow({ show: false });
      await w.loadURL(url);
      const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
      expect(bg).to.equal('red');
    });

    it('removes an extension through BrowserWindow.removeExtension', async () => {
      await (BrowserWindow.addExtension(path.join(fixtures, 'extensions', 'red-bg')) as any);
      BrowserWindow.removeExtension('red-bg');
      const w = new BrowserWindow({ show: false });
      await w.loadURL(url);
      const bg = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
      expect(bg).to.equal('');
    });
  });

  describe('chrome extension content scripts', () => {
    const fixtures = path.resolve(__dirname, 'fixtures');
    const extensionPath = path.resolve(fixtures, 'extensions');

    const addExtension = (name: string) => session.defaultSession.loadExtension(path.resolve(extensionPath, name));
    const removeAllExtensions = () => {
      Object.keys(session.defaultSession.getAllExtensions()).map(extName => {
        session.defaultSession.removeExtension(extName);
      });
    };

    let responseIdCounter = 0;
    const executeJavaScriptInFrame = (webContents: WebContents, frameRoutingId: number, code: string) => {
      return new Promise(resolve => {
        const responseId = responseIdCounter++;
        ipcMain.once(`executeJavaScriptInFrame_${responseId}`, (event, result) => {
          resolve(result);
        });
        webContents.send('executeJavaScriptInFrame', frameRoutingId, code, responseId);
      });
    };

    const generateTests = (sandboxEnabled: boolean, contextIsolationEnabled: boolean) => {
      describe(`with sandbox ${sandboxEnabled ? 'enabled' : 'disabled'} and context isolation ${contextIsolationEnabled ? 'enabled' : 'disabled'}`, () => {
        let w: BrowserWindow;

        describe('supports "run_at" option', () => {
          beforeEach(async () => {
            await closeWindow(w);
            w = new BrowserWindow({
              show: false,
              width: 400,
              height: 400,
              webPreferences: {
                contextIsolation: contextIsolationEnabled,
                sandbox: sandboxEnabled
              }
            });
          });

          afterEach(() => {
            removeAllExtensions();
            return closeWindow(w).then(() => { w = null as unknown as BrowserWindow; });
          });

          it('should run content script at document_start', async () => {
            await addExtension('content-script-document-start');
            w.webContents.once('dom-ready', async () => {
              const result = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
              expect(result).to.equal('red');
            });
            w.loadURL(url);
          });

          it('should run content script at document_idle', async () => {
            await addExtension('content-script-document-idle');
            w.loadURL(url);
            const result = await w.webContents.executeJavaScript('document.body.style.backgroundColor');
            expect(result).to.equal('red');
          });

          it('should run content script at document_end', async () => {
            await addExtension('content-script-document-end');
            w.webContents.once('did-finish-load', async () => {
              const result = await w.webContents.executeJavaScript('document.documentElement.style.backgroundColor');
              expect(result).to.equal('red');
            });
            w.loadURL(url);
          });
        });

        // TODO(nornagon): real extensions don't load on file: urls, so this
        // test needs to be updated to serve its content over http.
        describe.skip('supports "all_frames" option', () => {
          const contentScript = path.resolve(fixtures, 'extensions/content-script');

          // Computed style values
          const COLOR_RED = 'rgb(255, 0, 0)';
          const COLOR_BLUE = 'rgb(0, 0, 255)';
          const COLOR_TRANSPARENT = 'rgba(0, 0, 0, 0)';

          before(() => {
            BrowserWindow.addExtension(contentScript);
          });

          after(() => {
            BrowserWindow.removeExtension('content-script-test');
          });

          beforeEach(() => {
            w = new BrowserWindow({
              show: false,
              webPreferences: {
                // enable content script injection in subframes
                nodeIntegrationInSubFrames: true,
                preload: path.join(contentScript, 'all_frames-preload.js')
              }
            });
          });

          afterEach(() =>
            closeWindow(w).then(() => {
              w = null as unknown as BrowserWindow;
            })
          );

          it('applies matching rules in subframes', async () => {
            const detailsPromise = emittedNTimes(w.webContents, 'did-frame-finish-load', 2);
            w.loadFile(path.join(contentScript, 'frame-with-frame.html'));
            const frameEvents = await detailsPromise;
            await Promise.all(
              frameEvents.map(async frameEvent => {
                const [, isMainFrame, , frameRoutingId] = frameEvent;
                const result: any = await executeJavaScriptInFrame(
                  w.webContents,
                  frameRoutingId,
                  `(() => {
                    const a = document.getElementById('all_frames_enabled')
                    const b = document.getElementById('all_frames_disabled')
                    return {
                      enabledColor: getComputedStyle(a).backgroundColor,
                      disabledColor: getComputedStyle(b).backgroundColor
                    }
                  })()`
                );
                expect(result.enabledColor).to.equal(COLOR_RED);
                if (isMainFrame) {
                  expect(result.disabledColor).to.equal(COLOR_BLUE);
                } else {
                  expect(result.disabledColor).to.equal(COLOR_TRANSPARENT); // null color
                }
              })
            );
          });
        });
      });
    };

    generateTests(false, false);
    generateTests(false, true);
    generateTests(true, false);
    generateTests(true, true);
  });

  describe('extension ui pages', () => {
    afterEach(() => {
      session.defaultSession.getAllExtensions().forEach(e => {
        session.defaultSession.removeExtension(e.id);
      });
    });

    it('loads a ui page of an extension', async () => {
      const { id } = await session.defaultSession.loadExtension(path.join(fixtures, 'extensions', 'ui-page'));
      const w = new BrowserWindow({ show: false });
      await w.loadURL(`chrome-extension://${id}/bare-page.html`);
      const textContent = await w.webContents.executeJavaScript('document.body.textContent');
      expect(textContent).to.equal('ui page loaded ok\n');
    });

    it('can load resources', async () => {
      const { id } = await session.defaultSession.loadExtension(path.join(fixtures, 'extensions', 'ui-page'));
      const w = new BrowserWindow({ show: false });
      await w.loadURL(`chrome-extension://${id}/page-script-load.html`);
      const textContent = await w.webContents.executeJavaScript('document.body.textContent');
      expect(textContent).to.equal('script loaded ok\n');
    });
  });
});

ifdescribe(!process.electronBinding('features').isExtensionsEnabled())('chrome extensions', () => {
  const fixtures = path.resolve(__dirname, 'fixtures');
  let w: BrowserWindow;

  before(() => {
    BrowserWindow.addExtension(path.join(fixtures, 'extensions/chrome-api'));
  });

  after(() => {
    BrowserWindow.removeExtension('chrome-api');
  });

  beforeEach(() => {
    w = new BrowserWindow({ show: false });
  });

  afterEach(() => closeWindow(w).then(() => { w = null as unknown as BrowserWindow; }));

  it('chrome.runtime.connect parses arguments properly', async function () {
    await w.loadURL('about:blank');

    const promise = emittedOnce(w.webContents, 'console-message');

    const message = { method: 'connect' };
    w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

    const [,, responseString] = await promise;
    const response = JSON.parse(responseString);

    expect(response).to.be.true();
  });

  it('runtime.getManifest returns extension manifest', async () => {
    const actualManifest = (() => {
      const data = fs.readFileSync(path.join(fixtures, 'extensions/chrome-api/manifest.json'), 'utf-8');
      return JSON.parse(data);
    })();

    await w.loadURL('about:blank');

    const promise = emittedOnce(w.webContents, 'console-message');

    const message = { method: 'getManifest' };
    w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

    const [,, manifestString] = await promise;
    const manifest = JSON.parse(manifestString);

    expect(manifest.name).to.equal(actualManifest.name);
    expect(manifest.content_scripts).to.have.lengthOf(actualManifest.content_scripts.length);
  });

  it('chrome.tabs.sendMessage receives the response', async function () {
    await w.loadURL('about:blank');

    const promise = emittedOnce(w.webContents, 'console-message');

    const message = { method: 'sendMessage', args: ['Hello World!'] };
    w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

    const [,, responseString] = await promise;
    const response = JSON.parse(responseString);

    expect(response.message).to.equal('Hello World!');
    expect(response.tabId).to.equal(w.webContents.id);
  });

  it('chrome.tabs.executeScript receives the response', async function () {
    await w.loadURL('about:blank');

    const promise = emittedOnce(w.webContents, 'console-message');

    const message = { method: 'executeScript', args: ['1 + 2'] };
    w.webContents.executeJavaScript(`window.postMessage('${JSON.stringify(message)}', '*')`);

    const [,, responseString] = await promise;
    const response = JSON.parse(responseString);

    expect(response).to.equal(3);
  });

  describe('extensions and dev tools extensions', () => {
    let showPanelTimeoutId: NodeJS.Timeout | null = null;

    const showLastDevToolsPanel = (w: BrowserWindow) => {
      w.webContents.once('devtools-opened', () => {
        const show = () => {
          if (w == null || w.isDestroyed()) return;
          const { devToolsWebContents } = w as unknown as { devToolsWebContents: WebContents | undefined };
          if (devToolsWebContents == null || devToolsWebContents.isDestroyed()) {
            return;
          }

          const showLastPanel = () => {
            // this is executed in the devtools context, where UI is a global
            const { UI } = (window as any);
            const lastPanelId = UI.inspectorView._tabbedPane._tabs.peekLast().id;
            UI.inspectorView.showPanel(lastPanelId);
          };
          devToolsWebContents.executeJavaScript(`(${showLastPanel})()`, false).then(() => {
            showPanelTimeoutId = setTimeout(show, 100);
          });
        };
        showPanelTimeoutId = setTimeout(show, 100);
      });
    };

    afterEach(() => {
      if (showPanelTimeoutId != null) {
        clearTimeout(showPanelTimeoutId);
        showPanelTimeoutId = null;
      }
    });

    describe('BrowserWindow.addDevToolsExtension', () => {
      describe('for invalid extensions', () => {
        it('throws errors for missing manifest.json files', () => {
          const nonexistentExtensionPath = path.join(__dirname, 'does-not-exist');
          expect(() => {
            BrowserWindow.addDevToolsExtension(nonexistentExtensionPath);
          }).to.throw(/ENOENT: no such file or directory/);
        });

        it('throws errors for invalid manifest.json files', () => {
          const badManifestExtensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', 'bad-manifest');
          expect(() => {
            BrowserWindow.addDevToolsExtension(badManifestExtensionPath);
          }).to.throw(/Unexpected token }/);
        });
      });

      describe('for a valid extension', () => {
        const extensionName = 'foo';

        before(() => {
          const extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', 'foo');
          BrowserWindow.addDevToolsExtension(extensionPath);
          expect(BrowserWindow.getDevToolsExtensions()).to.have.property(extensionName);
        });

        after(() => {
          BrowserWindow.removeDevToolsExtension('foo');
          expect(BrowserWindow.getDevToolsExtensions()).to.not.have.property(extensionName);
        });

        describe('when the devtools is docked', () => {
          let message: any;
          let w: BrowserWindow;
          before(async () => {
            w = new BrowserWindow({ show: false, webPreferences: { nodeIntegration: true } });
            const p = new Promise(resolve => ipcMain.once('answer', (event, message) => {
              resolve(message);
            }));
            showLastDevToolsPanel(w);
            w.loadURL('about:blank');
            w.webContents.openDevTools({ mode: 'bottom' });
            message = await p;
          });
          after(closeAllWindows);

          describe('created extension info', function () {
            it('has proper "runtimeId"', async function () {
              expect(message).to.have.ownProperty('runtimeId');
              expect(message.runtimeId).to.equal(extensionName);
            });
            it('has "tabId" matching webContents id', function () {
              expect(message).to.have.ownProperty('tabId');
              expect(message.tabId).to.equal(w.webContents.id);
            });
            it('has "i18nString" with proper contents', function () {
              expect(message).to.have.ownProperty('i18nString');
              expect(message.i18nString).to.equal('foo - bar (baz)');
            });
            it('has "storageItems" with proper contents', function () {
              expect(message).to.have.ownProperty('storageItems');
              expect(message.storageItems).to.deep.equal({
                local: {
                  set: { hello: 'world', world: 'hello' },
                  remove: { world: 'hello' },
                  clear: {}
                },
                sync: {
                  set: { foo: 'bar', bar: 'foo' },
                  remove: { foo: 'bar' },
                  clear: {}
                }
              });
            });
          });
        });

        describe('when the devtools is undocked', () => {
          let message: any;
          let w: BrowserWindow;
          before(async () => {
            w = new BrowserWindow({ show: false, webPreferences: { nodeIntegration: true } });
            showLastDevToolsPanel(w);
            w.loadURL('about:blank');
            w.webContents.openDevTools({ mode: 'undocked' });
            message = await new Promise(resolve => ipcMain.once('answer', (event, message) => {
              resolve(message);
            }));
          });
          after(closeAllWindows);

          describe('created extension info', function () {
            it('has proper "runtimeId"', function () {
              expect(message).to.have.ownProperty('runtimeId');
              expect(message.runtimeId).to.equal(extensionName);
            });
            it('has "tabId" matching webContents id', function () {
              expect(message).to.have.ownProperty('tabId');
              expect(message.tabId).to.equal(w.webContents.id);
            });
          });
        });
      });
    });

    it('works when used with partitions', async () => {
      const w = new BrowserWindow({
        show: false,
        webPreferences: {
          nodeIntegration: true,
          partition: 'temp'
        }
      });

      const extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', 'foo');
      BrowserWindow.addDevToolsExtension(extensionPath);
      try {
        showLastDevToolsPanel(w);

        const p: Promise<any> = new Promise(resolve => ipcMain.once('answer', function (event, message) {
          resolve(message);
        }));

        w.loadURL('about:blank');
        w.webContents.openDevTools({ mode: 'bottom' });
        const message = await p;
        expect(message.runtimeId).to.equal('foo');
      } finally {
        BrowserWindow.removeDevToolsExtension('foo');
        await closeAllWindows();
      }
    });

    it('serializes the registered extensions on quit', () => {
      const extensionName = 'foo';
      const extensionPath = path.join(__dirname, 'fixtures', 'devtools-extensions', extensionName);
      const serializedPath = path.join(app.getPath('userData'), 'DevTools Extensions');

      BrowserWindow.addDevToolsExtension(extensionPath);
      app.emit('will-quit');
      expect(JSON.parse(fs.readFileSync(serializedPath, 'utf8'))).to.deep.equal([extensionPath]);

      BrowserWindow.removeDevToolsExtension(extensionName);
      app.emit('will-quit');
      expect(fs.existsSync(serializedPath)).to.be.false('file exists');
    });

    describe('BrowserWindow.addExtension', () => {
      it('throws errors for missing manifest.json files', () => {
        expect(() => {
          BrowserWindow.addExtension(path.join(__dirname, 'does-not-exist'));
        }).to.throw('ENOENT: no such file or directory');
      });

      it('throws errors for invalid manifest.json files', () => {
        expect(() => {
          BrowserWindow.addExtension(path.join(__dirname, 'fixtures', 'devtools-extensions', 'bad-manifest'));
        }).to.throw('Unexpected token }');
      });
    });
  });
});