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Minimal WebDriver

Build Status SemVer License

Pipe scripts to browsers using the Selenium WebDriver protocol.

  • SauceLabs support
  • Selenium Server 2 support
  • Concurrent test runs
  • No web server required


npm install min-wd


Put a config file name .min-wd in your project directory:

  "hostname": "localhost",
  "port": 4444,
  "browsers": [{
    "name": "internet explorer",
    "version": "10"
  }, {
    "name": "chrome"

You can also have the .min-wd file be loaded as a module:

var hostname = true ? "localhost" : "otherhost";
module.export = {
  "hostname": hostname,
  "port": 4444,
  "browsers": [{
    "name": "internet explorer",
    "version": "10"
  }, {
    "name": "chrome"

Alternatively, add a webdriver property with the configs to your package.json file.

Assuming my-script.js contains this:

console.log('Hello %s!', 'browser');

Use with browserify:

$ browserify -p min-wd my-script.js
# internet explorer 9:
Hello browser!
# chrome *:
Hello browser!


Export your SauceLabs credentials:

export SAUCE_USERNAME="your-user-name"
export SAUCE_ACCESS_KEY="your-access-key"

Enable SauceLabs in your .min-wd file:

  "sauceLabs": true,
  "browsers": [...]

See "Supported options" for additional SauceLabs specific options and "SauceLabs on Travis" on how to run min-webdriver tests on Travis.

Loading a web page

By default, min-webdriver will folk a new browser and inject the given script straight away without loading any web page. If you want to run your test cases in the context of a web page, you can configure the start page in the .min-wd file:

  "url": "http://my-test-page"

Mocha Support

Testing with Mocha requires mocaccino:

$ browserify -p mocaccino -p min-wd my-test.js

If this is your use case, make sure to give Mochify a try.


The default timeout for the log polling script is 10 seconds. If you have long running test cases that don't print anything for more than 10 seconds, you can increase the timeout by adding a timeout property to your config:

"timeout": 20000

Notice: This option is not used if explicitly setting the asyncPolling option to false.


Use min-wd programatically with browserify like this:

var browserify = require('browserify');
var minWd = require('min-wd');
var b = browserify();
b.plugin(minWd, { timeout : 0 });

Supported options

  • wdFile specify the location of the .min-wd config file. Defaults to .min-wd.
  • sauceLabs whether to run tests with saucelabs. Defaults to false.
  • hostname the host to connect to. Defaults to localhost. If sauceLabs is true, is used.
  • port the port to connect to. Defaults to 4444. If sauceLabs is true, 80 is used.
  • asyncPolling whether to use async polling when looking for test results. Defaults to true.
  • timeout if a script does not respond to log polling calls for this amount of milliseconds, the test run is aborted. Defaults to 10 seconds.
  • url the URL to open in each browser. Defaults to no URL.
  • closeOnSuccess whether to close browsers on success. Defaults to true.
  • closeOnError whether to close browsers on error. Defaults to true.
  • browsers an array of browser config objects, each with these properties:
    • name the name of the browser to launch, e.g. chrome, firefox or internet explorer
    • version the browser version to launch. Use * for any.
    • url an optional URL to launch for this browser

Some options are only considered depending on the asyncPolling value:

  • pollingInterval sets the time interval between test log checks. Only apply if asyncPolling is false. Defaults to 1000 milliseconds.
  • timeout option won't apply if asyncPolling is set to false because the test log is checked manually respecting pollingInterval.

SauceLabs specific options that only apply if sauceLabs is set to true:

  • sauceJobName sets a custom name for the SauceLabs job. If a package.json file exists in the current directory, this defaults to the package name.
  • BUILD_VAR sets the environment variable name that contains a build number to set, e.g. TRAVIS_BUILD_NUMBER.

SauceLabs on Travis

Assuming you have your linter and headless tests in an npm "test" script and the SauceLabs tests in a script called "wd", then the SauceLabs builds can be used by configuring your .travis.yml like this:

language: node_js
  - "0.12"
  - "4.2"
    - SAUCE_USERNAME=mantoni
    - secure: "your-secured-access-key"
  - 'npm test'
  - 'if [ "x$TRAVIS_NODE_VERSION" = "x4.2" ]; then npm run wd; fi'

This will run npm test on Node 0.12 and 4.2 while running the "wd" script only in the node 4.2 build. See the Travis documentation for encryption keys for details about the secure config.

Known issues and solutions

min-webdriver injects your script directly into the default page launched by the Selenium driver. In some cases browsers behave strangely in this context. Work around this by specifying a URL to a simple web page that is loaded before running the tests:

  "browsers": [{
    "name": "Internet Explorer",
    "version": "9",
    "url": "http://my-server/doctype.html"

With this content in the doctype.html:

<!DOCTYPE html><html><head><meta encoding="utf-8"></head><body></body></html>

You can also specify a "url" for all browser on the root level.

Loading a page before injecting the scripts is solving these issues:

  • IE 9 reporting it can't find JSON because the Selenium default page makes IE switch to quirks mode
  • Error: SECURITY_ERR: DOM Exception 18 because setting cookies is not allowed for file:// URLs
  • Error: access to the Indexed Database API is denied in this context
  • localStorage being inaccessible.

Usage with Microsoft Edge browser

To configure edge use { "name": "microsoftedge" }. For the time being, MS Edge doesn't support asyncPolling set to true. If you want to test with that browser you must set asyncPolling to false.


  • Node 0.10, 0.12, 4.x, 5.x
  • Selenium Server 2.39 or later