Skip to content


Subversion checkout URL

You can clone with
Download ZIP
The YUI Easy Testing Interface: run browser JS unit tests from the command line!
JavaScript Shell

Fetching latest commit…

Cannot retrieve the latest commit at this time

Failed to load latest commit information.


Build Status

Yeti is a command-line tool for launching JavaScript unit tests in a browser and reporting the results without leaving your terminal. Yeti is designed to work with tests built on YUI Test just as they are.

Using Yeti

Running a test

Just run Yeti with the HTML files containing your tests.

$ yeti test/*.html
Creating a Hub at http://localhost:9000
Waiting for agents to connect at http://localhost:9000.
When ready, press Enter to begin testing.

Point your browsers at that URL, then come back and press Enter.

[Open some browsers...]

  Agent connected: Safari (6.0) / Mac OS
  Agent connected: Chrome (22.0.1221.0) / Mac OS

[Come back, press Enter]

✔ Testing started on Safari (6.0) / Mac OS, Chrome (22.0.1221.0) / Mac OS
Testing... / 86% complete (19/22) 121.99 tests/sec ✔ Agent completed: Safari (6.0) / Mac OS
Testing... | 95% complete (21/22) 115.40 tests/sec ✔ Agent completed: Chrome (22.0.1221.0) / Mac OS
Testing... \ 100% complete (22/22) 115.23 tests/sec 504 tests passed! (9164ms)

Yeti exits automatically when all tests complete. If test failures occur, Yeti will exit with a non-zero status code.

Code coverage

Yeti automatically includes a line coverage summary if your tests were instrumented with [YUI Test Coverage][yuitest].

✔ Testing started on Safari (6.0) / Mac OS
Testing... \ 13% complete (10/60) 11.85 tests/sec 44% line coverage

Yeti Hub

To save time, start a Yeti Hub.

$ yeti --server
Yeti Hub listening on port 9000.

Point browsers at your local Yeti on port 9000. Now, you're ready to run tests without having to reconnect browsers each time.

Starting Yeti in another terminal will connect to that Hub instead of starting a new one and will begin testing immediately if browsers are already connected.

$ yeti test/*.html
Connected to http://localhost:9000
  Agent connected: Chrome (22.0.1221.0) / Mac OS
  Agent connected: Safari (6.0) / Mac OS
✔ Testing started on Chrome (22.0.1221.0) / Mac OS, Safari (6.0) / Mac OS
Testing... / 68% complete (15/22) 98.84 tests/sec ✔ Agent completed: Chrome (22.0.1221.0) / Mac OS
Testing... | 95% complete (21/22) 91.65 tests/sec ✔ Agent completed: Safari (6.0) / Mac OS
Testing... \ 100% complete (22/22) 91.60 tests/sec 504 tests passed! (11529ms)

Sharing Your Yeti Hub

Your Yeti Hub can be shared with other developers.

First, I'll start a Hub on on port 80.

$ yeti --server --port 80

Go ahead and point a few browsers there.

Now, others can connect to it from their computer like so:

$ yeti --hub test/*.html
Connected to
Waiting for agents to connect at
When ready, press Enter to begin testing.

Your pwd and your test file will be served through the Hub. Like magic.

[Hit Enter]
  Agent connected: Chrome (22.0.1221.0) / Mac OS
  Agent connected: Safari (6.0) / Mac OS
✔ Testing started on Chrome (22.0.1221.0) / Mac OS, Safari (6.0) / Mac OS
Testing... - 91% complete (20/22) 122.51 tests/sec ✔ Agent completed: Safari (6.0) / Mac OS
Testing... | 95% complete (21/22) 120.21 tests/sec ✔ Agent completed: Chrome (22.0.1221.0) / Mac OS
Testing... \ 100% complete (22/22) 120.05 tests/sec 504 tests passed! (8763ms)

This makes it really simple to setup an ad-hoc testing lab shared with your team.


Yeti will disconnect a browser if it does not record any activity from it for 45 seconds. You can adjust this interval with the --timeout option.

This will run Yeti with a 120 second timeout:

$ yeti --timeout 120 test.html

Query string parameters

Yeti can include a query string parameter to add to your test URLs. This can be used to pass information to your tests that control its behavior.

This will append ?fliter=coverage to your tests, which is used by the tests for the YUI Library to trigger loading instrumented code.

$ yeti --query 'filter=coverage' test/*.html

Error handling

Yeti will report an uncaught exceptions as Script Errors.

Yeti enforces No-Quirks Mode in your tests because it may impact DOM-related APIs. Add a DOCTYPE to your test document to fix this.

Mobile testing made easy

When combined with localtunnel, mobile testing is simple. If you're not dealing with sensitive information, startup your Yeti Hub and then run:

$ localtunnel 9000
   Port 9000 is now publicly accessible from ...

You can then visit that URL on your mobile (or any other) device and have it run new tests.

Yeti API

You can require("yeti") inside your application to script Yeti for your own use.

For API documentation:

  • Run make html to build HTML documentation to ./build_docs.
  • Review code comments inside lib/yeti.js, lib/client.js and lib/hub/index.js.

Yeti follows Semantic Versioning but is currently at a 0.x.y release. The public API is not stable. There will be changes.


Yeti should work on all platforms supported by Node.js. It's tested on Linux and OS X.

You must start Yeti's client in the directory you'll be serving tests from. For security reasons, Yeti will reject requests that try to access files outside of the directory you start Yeti in.


Yeti requires Node.js v0.6 or v0.8.

Latest snapshot

# Install Yeti from the latest source from GitHub's yui/yeti repo.
npm install -g

Latest release

If you have problems with the latest Yeti, you may install the last stable release instead:

npm install -g yeti


Installing localtunnel helps proxy Yeti outside of your firewall. It's available as a Ruby gem:

gem install localtunnel

Develop Yeti

Do you want to add new features or fix bugs in Yeti itself? We made it easy for you to hack on Yeti.

Experimental: Develop on Windows

After running npm install, replace the make commands below with .\jake.bat to use the experimental Jake tasks that are Windows ready.

Install dependencies

Clone Yeti.

git clone
cd yeti

Install Yeti's devDependencies.

npm install

Yeti's automated tests use PhantomJS. Install it.

# For Mac OS X and Homebrew:
brew update
brew install phantomjs

Run tests

Requires PhantomJS to be installed.

make test

Code coverage

Requires PhantomJS to be installed.

make coverage

This command uses JSCoverage for Node.js, which will be built and installed to ./tools/jscoverage.

HTML documentation


Documentation will be built to build_docs/.

make html

Yeti uses Selleck to generate its website. Selleck files are located in doc/.

JavaScript API

Documentation will be built to build_docs/api/everything/.

make html-api

Yeti uses YUIDocJS to generate API documentation from inline JSDoc comment blocks.


make lint

You may also run the linter on individual files with ./go lint:

./go lint test/blizzard.js

Yeti uses JSHint to analyze code for problems. See .jshintrc for options used by Yeti.


Requires Google Chrome Canary and Mac OS X.

Profile the Yeti Hub:

./go profile --server

Using ./go profile without --server to profile the Yeti client requires an interactive terminal, which does not yet work.

Contribute to Yeti

Your contributions are welcome! Please review the YUI contributor guide before contributing.

If you haven't contributed to a YUI project before, you'll need to review and sign the YUI CLA before we can accept your pull request.

Contribution Checklist

  1. Run make lint and make sure your new code runs through the linter without error.
  2. Run make coverage and make sure your new code is covered with a test. Tests are located in test and use Vows.

Bugs & Feedback

Open a ticket on's Yeti Issue Tracker to report bugs or feature requests.

Yeti is an experimental project of YUI Labs. As such, it doesn't receive the same level of support as other mature YUI projects.


Yeti is free to use under YUI's BSD license. See the LICENSE file or the YUI license page for license text and copyright information.

Something went wrong with that request. Please try again.