Javascript Unit Test Framework
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Javascript Unit Testing Environment (JUTE)


JUTE enables unobtrusive, automated JavaScript YUI3 unit testing with code coverage. Command line and web-based interfaces make JUTE easy to integrate with Hudson, developers, and even (gasp!) managers. There are 3 backends available to test your code: Selenium (1, 2, and grid), Capture, PhantomJS/WebKit, and V8.


NodeJS .4 compiled with SSL support

npm 1.x

java (any modern version should do)

Super Quick Start


JUTE is a standalone HTTP server that serves your test files to a JUTE backend for testing. Three of the four backends (Selenium, Capture, and PhantomJS) serve files to a browser, the third backend (V8) will run your tests directly in V8. JUTE then collects and stores test output in JUnit XML format and code coverage information in 'lcov' format and generates pretty HTML to view your coverage results. That is it!

Variable Setup

To do its magic JUTE need some information from you. All configuration variables are provided by 'npm' using npm config variables. See

% npm help config

For gory details. But simply:

% npm config set jute:port 80

Will set the port the JUTE webserver listens on to 80. You must 'npm restart jute -g' for any setting changesto take effect!

Here are some important JUTE configuration variables and their defaults:

            port:           8080
            docRoot:        '/var/www/'
            testDir:        'test/'
            outputDir:      'output/'
            java:           '/usr/bin/java'
            logfile:        '/tmp/jute.log'
            pidfile:        '/tmp/'
            phantomjs:      '/usr/local/bin/phantomjs'

To set any of these do:

% npm config set jute:<variable> <value>


% npm config set jute:docRoot /var/htmlroot

What the variables mean:

  • port: Port JUTE should listen on
  • docRoot: Your document root
  • testDir: A directory RELATIVE to docRoot where all your Javascript test files live
  • outputDir: A directory REALTIVE to docRoot where JUTE will dump output (test results and code coverage information)
  • java: Location of 'java' executable
  • logfile: Where JUTE dumps debug output
  • pidfile: Where JUTE keeps its PID
  • phantomjs: Path to 'phantomjs' executable

You MUST restart JUTE after you change any variable:

% npm restart jute -g

Install JUTE

% npm install jute -g

Start JUTE

% npm start jute -g

That will dump output to STDOUT & JUTE does NOT self-daemonize SO in reality you probably really want something like:

% nohup npm start jute -g 2>&1 > LOGFILE &

The JUTE server is now running as YOU - keep that in mind if you want to listen on priviliedged ports...

Connect to JUTE

Point your browser to the host your started JUTE on - make sure the port is correct (port 8080 by default)!

Click on a test & run it!

In-Depth Start

JUTE output directory

JUTE writes unit test results and optionally coverage information into an output directory. By default this output directory is docRoot/output. Ensure the user JUTE runs as can write to this directory! You can change the directory name by:

% npm config set:outputDir juteOutput

Now it will put output files into docRoot/juteOutput

You must restart JUTE after changing this setting:

% npm restart jute

JUTE test directory

By default JUTE looks in docRoot/test for test HTML files. This can be changed:

% npm config set:testDir juteTests

Now it will look for test files in docRoot/juteTests

You must restart JUTE after changing this setting:

% npm restart jute

Starting and Stopping JUTE

JUTE is a standalone HTTP server. You control when JUTE is running

% npm start jute -g
% npm stop jute -g
% npm restart jute -g

JUTE Backends


This is the default mode for the JUTE UI. Any captured browsers (see 'Browsers' below) will run any submitted unit tests in parallel. To capture a browser point it to:


The browser is now 'captured'. Any submitted unit tests will be run in parallel through all currently captured browsers.

Each captured browser will create a test results file whose name contains the modified user agent string of that browser (so you can tell them apart).

However only ONE code coverage output file will be created regardless of how many browsers are connected.

When you click to run (a) unit test(s) in the JUTE UI the test(s) will be run in 'capture' mode - meaning any captured browser will run the selected test(s).


This mode can currently only be accessed via the command line tool 'jute_submit_test'. See below for documentation. Basically you submit tests from the command line too 'jute_submit_test' along with your Selenium RC or Grid host (and an optional Selenium browser specification)

Tests are expected to be in the standard test location and output will go into the standard output location as detailed above.

To use WebDriver (Selenium2) you must use the '--sel2' flag on the command line


This mode can currently only be accessed via the command line tool 'jute_submit_test'. See below for documentation. Basically you submit tests from the command line too 'jute_submit_test' along with the '--v8' command line option.

Tests are expected to be in the standard test location and output will go into the standard output location as detailed above. Note NOT all client-side javascript unit tests are guaranteed to run in the V8 backend!! Tests which require browser-y features like event simulation will not run as mouseclicks and keyevents and the like do not exist in nodejs. HOWEVER DOM manipulation DOES work thanks to jsdom - which is provided by the nodejs-ized YUI3 - which JUTE automatically installs for you.


PhantomJS is standalone (potentially) headless WebKit. This backend behaves similarly to Selenium but without the need of a head! Further ANY client-side unit test should run just fine as Webkit has both a Javascript parser and DOM support built in.

If you have PhantomJS installed point JUTE to the location of the 'phantomjs' executable the 'phantomjs'. JUTE will run fine regardless of if you're using a 'real' X Server or Xvfb. And yes there is snapshot support.

This mode can currently only be accessed via the command line tool 'jute_submit_test'. See below for documentation. Basically you submit tests from the command line too 'jute_submit_test' along with the '--phantomjs' command line option.

Tests are expected to be in the standard test location and output will go into the standard output location as detailed above.

Using JUTE


Now that JUTE is up and running you can contact it here:


This browser is now 'captured' and is ready to run unit tests. Here is what you are seeing:

JUTE UI Status


This lists all the currently captured browsers. Any submitted unit tests (that are not meant for Selenium (more below)) will be run in parallel in each of the captured browsers.


These are list of currently running/queued tests. A highlighted row means that test is currently running. You can watch tests running and being popped off the stack and subsequent tests run. These are the tests for this captured browser specifically. Browsers will run tests at different speeds.

Test Files

The middle panel is the list of all the test files JUTE knows about. If you do not see any files here JUTE is misconfigured. Look above at the 'docRoot' and 'testDir' setting and ensure they are set properly.

Running a Single Test

Click on the test file link to run that test immediately without coverage. When running a single test the output will remain in the center panel (so you can see it) until you click 'Kick Lower Frame' to go back to the test listing.

Running Multiple Tests

Clicking the checkboxes allows you to run multiple tests, either with or without coverage.

Clicking the top checkboxes will select or unselect all tests in that column.

Click 'Run Tests' to run selected tests.

After running multiple tests the middle panel will return to the list of unit tests.

Kick Lower Frame

This button reloads the list of unit tests in the center panel. Espeically handy after running a single unit test.

Clear Tests

This button deletes any pending/queued unit tests

Clear Results

This will clear all results - both unit test results and coverage information


This column allows you to see the unit test results and code coverage information. For each browser there will be unit test output. Note this output is XML and the file contents may NOT be visible in your browser. 'View Source' if this is the case. A green link means all tests passed successfully and red link means at least one test failed. If you requested code coverage it will also show up here. Note results are shown for Capture, Selenium, and V8 tests even though you can only kick off Capture tests from the WebUI.

Command Line

The script


Is the main command line interface to JUTE. This script allows you to submit unit tests to JUTE to run either in Capture, Selenium, or V8 mode. Do:

% jute_submit_test --help

For help.


Submitting Tests

There are several ways to submit unit tests. You must specify ONLY relative path from the testDir directory you defined above.

One Test
jute_submit_test --test path/to/my/test/index.html

Note the docRoot/testDir will be prepended to the specified file.

Multiple Tests

On command line:

jute_submit_test --test path/to/my/test/index.html --test path/to/other/test/index.html --test path/to/other/other/test.html
jute_submit_test --test -

jute_submit_test accept a test filename per line until EOF

Running tests through Selenium

Specify --sel_host to run the submitted tests through Selenium. You can optionally also supply -sel_browser to give a Selenium browser specification. -sel_browser defaults to '*firefox'.

jute_submit_test --sel_host [ --sel_browser '*ieexplore' ] --test path/to/test/index.html

Of course --sel_host can either point to an individual Selenium RC host or a Selenium grid host.

Note the docRoot/testDir prepended to the specified test files.

For Selenium2 (WebDriver) use:

jute_submit_test --sel_host [ --sel_browser firefox ] --test path/to/test/index.html --sel2

Selenium Snapshots

When running your tests thru Selenium you can get a screen snapshot of your test! If ANY Selenium test fails JUTE will take a screenshot which will be available along with all the usual test output.

If you specify '--snapshot' JUTE will ALWAYS take a screen snapshot AT THE END of ALL the tests from the *.html file. So:

jute_submit_test --sel_host --snapshot --test path/to/test/index.html

Will generate a screenshot of the browser when all tests included by index.html are complete.

For Selenium2 (WebDriver):

jute_submit_test --sel_host --snapshot --test path/to/test/index.html --sel2

Paralellized Selenium tests via Selenium Grid

IF you have a Selenium grid set up AND would like to paralellize your unit tests thru it ensure your remote-controls all provide the same environment (like *firefox).

Now using the '--seleniums <#>' command line option you can specify how many remote-controls for Selenium Grid you want to spawn in parallel to run all of the submitted unit tests - SO:

jute_submit_test --sel_host --seleniums 5 --test path/to/test/index.html --test path/to/other/test.html ....

Or even better to specify a krap-load of tests at once:

cd /path/to/tests && find . -name '*.html' -printf '%p?do_coverage=1\n' | jute_submit_test --sel_host --seleniums 5 --test -

This will attempt to spawn off 5 Selenium Grid remote-controls - EACH WILL RUN 20% OF THE TESTS - to run your tests 5x faster.

Note this is DIFFERENT than capture mode testing where ALL tests run through ALL browsers - in this case EACH browser gets 1/5th of the total number of tests. This is because each remote-control is exactly the same!

Running tests through V8

Specify '--v8' on the command line and all of the specified tests will be run through V8.

% --v8 --test path/to/test/index.html

OR any other permutation of test specification as outlined above.

Running tests through PhantomJS

Once you have set the 'phantomjs' npm variable you can use the PhantomJS backend.

Specify --phantomjs to run the submitted tests through PhantomJS:

jute_submit_test --phantomjs --test path/to/test/index.html

Currently the PhantomJS backend will snapshot EVERY test regardless of success or failure.

Specifying code coverage

Note code coverage is now enabled BY DEFAULT!

If you do NOT want code coverage use the '?do_coverage=0' query string.

% jute_submit_test --test path/to/my/test/index.html?do_coverage=0


% jute_submit_test --sel_host --test path/to/test/index.html?do_coverage=0


% jute_submit_test --test path/to/my/test/index.html?do_coverage=0 --test path/to/other/test/index.html --test path/to/other/other/test.html

!! NOTE docRoot/testDir will be prepended to the specified test files. !!

Again by default JUTE ALWAYS generates code coverage information

JUTE Output

JUTE output all goes into the outputDir as specified above. outputDir is RELATIVE to docRoot so actual test output will be in docRoot/outputDir. Within that directory will be a directory for each unit test. The name of the directory is the NAME OF THE TEST SUITE as specified in your javascript test file. This will be explained in more detail below.

Note both test results and coverage information are available for easy viewing via the JUTE WebUI

Test Results

For each browser an XML file will be created. The name of the XML file is a modified version of the USER AGENT string of that browser. An example:


This unit test was run in the Chrome browser an Intel Mac OS version 10.5.8.

The format of this file is JUnit XML style test output recognizable by most tools including Hudson.

This looks like:

       <testsuite name="" tests="3" failures="0" time="0.021">
           <testcase name="testLoggerNotInitialized" time="0.001"><testcase>
           <testcase name="testInitRocketStats" time="0.001"><testcase>
           <testcase name="testLoggerInititialized" time="0"> <testcase>
       <testsuite name="" tests="4" failures="0" time="0.025">
           <testcase name="testGetTheInitializedLoggerObject" time="0"> <testcase>
           <testcase name="testLoggerHasCorrectLogLevels" time="0.001"> <testcase>
           <testcase name="testLoggerHasRightNumberOfAppenders" time="0.001"><testcase>
           <testcase name="testAddAppenderToLogger" time="0.001"><testcase>

Coverage Output

The the same directory as the test result output will be a directory named 'lcov-report'. In that directory will be an index.html file you can load into your browser to see coverage results. JUTE uses yuitest_coverage to instrument and exact coverage information form the requested Javascript files. See below for how to tell JUTE to instrument selected Javascript files for code coverage.

Also in the same directory is a '' file - which has your code coverage information in the standardized 'lcov' format if you want to run any other tools on it.

Writing Unit Tests for JUTE

JUTE requires VERY LITTLE from the developer to have their unit tests incorporated into the JUTE framework. Any new or already-written Unit Tests can easily be added to the JUTE framework.

The YUI3 test module

The main requirement is using the YUI3 Test and Assertion Framework for running and creating your Unit Tests. Look here for detailed information about getting started with YUI3 test module, including running, asserting, and potentially mocking objects for your unit tests.

Note you must use YUI3 version 3.1.1+.

Code Requirements

To utilize JUTE you DO NOT ANY CHANGES to your test YUI3-based Javascript test files! Look at the client-side examples to see a standard YUI3 unit test.

Require the YUI3 seed (3.1+) in your test HTML file

&lt;script src="" charset="utf-8">&lt;/script>

'Tag' the file(s) you are testing to be code coverage'd

&lt;script src="toolbar.js?coverage=1" charset="utf-8">&lt;/script>

Here we are testing code in the 'toolbar.js' file - and telling JUTE that IF the test is run with code coverage turned on to generate code coverage infomation for this file. You can have multiple files being tested that you want code coverage generated for - just tack the '?coverage=1' querystring onto them and JUTE will hook you up.

Write your unit tests!

V8 Caveats

Not all client-side unit tests will run in the V8 backend!! Event simulation is not supported. Crazy iframe stuff can be problematic. Anything expecting a real browser will be disappointed. All the basic DOM manipulation is available, UI events are not. No mouse events, No key events, No focus events. So be safe out there!

Testing NodeJS Code

So far we have primarily been talking about testing client-side code - FEAR NOT!! You can also easily test NodeJS server-side code jute as easily!! Of course you can only test NodeJS code using the V8 backend. But you can use the YUI test framework and generate code coverage no problem! Let's see what that looks like:

Here is a sample NodeJS module called 'spiffy.js':

module.exports = (function() {
    var spiffy = 'SPIF!';
    return function() { return spiffy };

Here is a Javascript test file for that module using JUTE:

    logInclude: { TestRunner: true },
}).use('test', function(Y) {

    var suite  = new Y.Test.Suite('spiffy'),
        spiffy = require('./spiffy', true), // 'true' here means do code coverae on it!
        fs      = require('fs');

    suite.add(new Y.Test.Case({
        name: 'spiffy test!',
        testSpiff: function() {
            Y.Assert.areEqual(spiffy(), 'SPIF!');


SNAZZY!!! Run it like this:

% jute_submit_test --v8 --test ./testSpiffy.js

To run with code coveage for spiffy.js:

% jute_submit_test --v8 --test ./testSpiffy.js?do_coverage=1

This will, like for client-side code, generate coverage information for all modules with require('', true) EXECPT NATIVE MODULES like 'fs' or 'sys', &c. You CAN however generate code coverage for other npm modules your code may use if you are curious.

Things to Note

  • We told 'jute_submit_test' to load a JAVASCRIPT file, NOT an HTML one
  • YUI3 was automatically imported for us
  • Look at the the 'require' statement where we imported our 'spiffy' module - note it has an extra parameter!!!! If this parameter is 'true' then JUTE will generate code coverage for it - exactly similar to adding the '?coverage=1' query string in your client-side HTML file.

Writing unit tests for NodeJS with code coverage has never been easier!!!


If you set the JUTE_DEBUG environment variable:

% export JUTE_DEBUG=1

You'll see even more gory debug output.

Developer Environment

Point jute.docRoot to your development environment - ideally your tests are set up in a separate directory tree that mirrors your source directory tree. Regardless any *.html file will be picked up by JUTE under docRoot/testDir.

Developer Build Environment

A Captured Browser

a local dev build can run all available unit tests - if they're all in a 'test' directory the command to run the tests can be as easy as:

    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --test {}?do_coverage=$(DO_COVERAGE) --wait \\; -print

DO_COVERAGE can be set to '1' to generate coverage reports:

% make run_unit_tests DO_COVERAGE=1

Note this assumes you have at least 1 captured browser. This will run all of your unit tests with code coverage.

You can of course also select all checkboxes in the webui and the result is the same.


    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --v8 --test {}?$(DO_COVERAGE) \\;

All output will go to STDOUT.


    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --phantomjs --test {}?$(DO_COVERAGE) \\;

All output will go to STDOUT.


All of your tests can be run thru Selenium - they all need to submitted at once to run as one job:

    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -printf '%p?do_coverage=$(DO_COVERAGE)\\n' | --test - --sel_host $(SEL_HOST) --sel_browser $(SEL_BROWSER) --send_output

This will return once all tests have run.

For Selenium2 append the '--sel2' option

Hudson Build Environment

Ensure Hudson is configured correctly to look in the output directory for test results and code coverage. If a unit test fails Hudson will label the build 'Unstable'. Clicking thru the "Test Results" will reveal the failed test(s).

Build/Hudson integration

Running tests and result and code coverage information are easily integrated into your builds and Hudson.

Running Tests


  • LOCAL_TEST_DIR is the root of where your test files live on the build or local host (testDir)
  • SEL_HOST is the hostname/IP of your Selenium box or grid
  • SEL_BROWSER is '*firefox' or '*iexplore' or whatever browser specification you want to use
  • DO_COVERAGE is 1 or 0 depending on if you want coverage (you probably do)


Running JUTE/browser tests locally is a simple Makefile rule.

Captured Browser(s)

    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --test {}?do_coverage=$(DO_COVERAGE} --wait \\; -print


    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -printf '%p?do_coverage=$(DO_COVERAGE)\\n' | jute_submit_test --test - --sel_host $(SEL_HOST) --sel_browser $(SEL_BROWSER) --send_output 

Append '--sel2' for Selenium2/WebDriver


    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --v8 --test {}?$(DO_COVERAGE} \\; 


    cd $(LOCAL_TEST_DIR) && find . -not \\( -path "*/.svn/*" \\) -name '*.html' -exec jute_submit_test --phantomjs --test {}?$(DO_COVERAGE} \\; 

Viewing Test Results

Output Directory

All results are stored in outputDir - you can look at the *.xml files to view the raw JUnit XML output.


http://<jute host>:<jute port>/

& click on links in the 'Results' column - this will show results for captured, Selenium, PhantomJS, and V8 tests.

Hudson Code Coverage

Running individual tests will generate a directory hierarchy rooted at your output_dir. The first thing you need to do is to aggregate all the individual coverage output into one mongo output files containing all the the individual output files.

This can be accomplished by a simple Makefile rule:

LCOV_GENHTML = /usr/local/bin/genhtml # Freely available - probably already installed!
OUTPUT_DIR = <outputDir>
    /bin/rm -f /tmp/
    @echo "OUTPUT DIR: ${OUTPUT_DIR}"
    find $(OUTPUT_DIR) -name -exec cat {} >> /tmp/ \\;
    @cp /tmp/ $(TOTAL_LCOV_FILE)
    @ls ${OUTPUT_DIR}
    /bin/rm -rf $(OUTPUT_DIR)/lcov-report
    $(LCOV_GENHTML) -o $(OUTPUT_DIR)/lcov-report $(TOTAL_LCOV_FILE)

Now simply point Hudson to this aggregated '' file - check 'Publish Lcov Coverage Report' and set ' file mask' to something similar to '<outputDir>/' depending on where your outputDir is relative to your workspace root.

Instead of 'cat'ing all the files together - IF there is overlap of the same JS files in multiple lcov.out files you should use 'lcov -a' instead.


Please file all JUTE issues here on github: JUTE Issue Tracker


This software is licensed under the BSD license available at