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Integrating Selenium and Hudson

Hudson http://hudson-ci.org/ is a continuous integration server - it runs and monitors ‘jobs’ in a way that is useful to regularly build software and report on any errors.

Selenium http://seleniumhq.org/ is a suite of tools specifically for testing web applications - it tests the full website by automating the running of one or more browsers (so you can test all that pointy clicky ajaxy stuff)

You can generate selenium tests with a firefox plugin http://seleniumhq.org/projects/ide/ basic tests can be generated just by recording your actions on a website - and saved as an html test suite.

The seleniumhq plugin for hudson http://wiki.hudson-ci.org/display/HUDSON/Seleniumhq+Plugin will start the seleniumrc server, run this test suite, monitor test/failure status and display the selenium report. 

Just add this plugin to hudson, ensure you have the seleniumrc jar file available and configured in the global settings page.

If you are running hudson on your local development system you may just need to download all the components and configure a job for it to just work. BUT if you want to run these jobs on a machine you are not logged in to you will need to run Xvfb to provide a fake display that the browser can use. 

I’ve done this by

setting the environment variable DISPLAY to :99

running the following shell script before the selenium test suite

Xvfb :99 -fp /usr/share/X11/fonts/misc -screen 0 1024x768x24 > xvfb.log 2&>1 &
echo $! > xvfp.pid

The SeleniumHQ testSuite config needs to know which browser to use, the staturl, where to find the tests and where to log the results 

kill $(cat xvfp.pid) rm xvfb.pid

and checked the "Publish Selenium Report" option - configured to match the results file as above.

I had hoped that I could export the DISPLAY variable within the script but that didn’t work - the environment variable setting is global so I’ve limited hudson to run one job at a time as they all share a display.

I have redirected all output from xvfb to a logfile otherwise hudson complains about leaking file descriptors.

So far this is great - my tests get run regularly and reported consistently over time.

But these tests are written in selenese (an html table based markup) which while having a great deal to offer does not have the full power of a programming language so my next step is to run tests via phpunit (this way I can access the database, loop over my test suite for a range of browsers, and more)

This time I need to manage starting the selenium server as well as xvfb

Xvfb :99   -screen 0 1024x768x24 &> xvfb.log & echo $! > xvfb.pid export DISPLAY=:99 sleep 10 java -jar /path-to/selenium-server.jar &> selenium.log & echo $! > selenium.pid sleep 30

phpunit –log-xml phpunit.xml Example.php

kill $(cat xvfb.pid) rm xvfb.pid kill $(cat selenium.pid) rm selenium.pid    

I have instructed phpunit to log in xml format (aka junit format in more recent versions - but I’m running an old version of debian at the moment)

I added the xunit plugin http://wiki.hudson-ci.org/display/HUDSON/xUnit+Plugin to hudson and configured "Publish JUnit test result report" for my project specifying phpunit.xml as in the above script.

It’s worth noting that Drupals simpletest can also provide output in junit format at least according to http://drupal.org/node/1024426 so it should be possible to mix test types and aggregate the reports.

So now it all seems to be working an I can run all my tests overnight - all software has bugs - but at least now we should see fewer bugs reoccur as we’ll keep adding tests to prevent these things creeping up on us.

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