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0.0.46 • Public • Published


This module helps testing VS Code web extensions locally.

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See the web extensions guide to learn about web extensions.

The node module runs a local web server that serves VS Code in the browser including the extension under development. Additionally the extension tests are automatically run.

The node module provides a command line as well as an API.


Via command line:

Test a web extension in a browser:

vscode-test-web --browserType=chromium --extensionDevelopmentPath=$extensionLocation

Run web extension tests:

vscode-test-web --browserType=chromium --extensionDevelopmentPath=$extensionLocation --extensionTestsPath=$extensionLocation/dist/web/test/suite/index.js

Open VS Code in the Browser on a folder with test data from the local disk:

vscode-test-web --browserType=chromium --extensionDevelopmentPath=$extensionLocation $testDataLocation

VS Code for the Web will open on a virtual workspace (scheme vscode-test-web), backed by a file system provider that gets the file/folder data from the local disk. Changes to the file system are kept in memory and are not written back to disk.

Via API:

async function go() {
  try {
    // The folder containing the Extension Manifest package.json
    const extensionDevelopmentPath = path.resolve(__dirname, '../../../');

    // The path to module with the test runner and tests
    const extensionTestsPath = path.resolve(__dirname, './suite/index');

    // Start a web server that serves VSCode in a browser, run the tests
    await runTests({
		browserType: 'chromium',
  } catch (err) {
    console.error('Failed to run tests');


CLI options:

Option Argument Description
--browser The browser to launch: chromium (default), firefox, webkit or none.
--extensionDevelopmentPath A path pointing to an extension under development to include.
--extensionTestsPath A path to a test module to run.
--quality insiders (default), or stable. Ignored when sourcesPath is provided.
--sourcesPath If set, runs the server from VS Code sources located at the given path. Make sure the sources and extensions are compiled (yarn compile and yarn compile-web).
--headless If set, hides the browser. Defaults to true when an extensionTestsPath is provided, otherwise false.
--permission Permission granted to the opened browser: e.g. clipboard-read, clipboard-write. See full list of options. Argument can be provided multiple times.
--coi If set, enables cross origin isolation. Defaults to false.
--folder-uri URI of the workspace to open VS Code on. Ignored when folderPath is provided.
--extensionPath A path pointing to a folder containing additional extensions to include. Argument can be provided multiple times.
--extensionId The id of an extension include. The format is ${publisher}.${name}. Append @prerelease to use the prerelease version.
--host The host name the server is opened on. Defaults to localhost.
--port The port the server is opened on. Defaults to 3000.
--open-devtools If set, opens the dev tools in the browser.
--verbose If set, prints out more information when running the server.
--printServerLog If set, prints the server access log.
--testRunnerDataDir If set, the temporary folder for storing the VS Code builds used for running the tests
folderPath A local folder to open VS Code on. The folder content will be available as a virtual file system and opened as workspace.

Corresponding options are available in the API.


  • yarn && yarn install-extensions

  • Make necessary changes in src

  • yarn compile (or yarn watch)

  • run yarn sample to launch VS Code Browser with the sample extension bundled in this repo.

  • run yarn sample-tests to launch VS Code Browser running the extension tests of the sample extension bundled in this repo.




This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.




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