- 4 minutes read #Mozilla , #developer

Automated javascript unit-tests with xpcshell and Hudson

I’m currently re-writing a Thunderbird plugin – and in the last few years have caught the unit-testing and test driven development bug… So, how do I make my life easy by integrating Hudson and Thunderbird?

It turned out to be suprisingly difficult, here’s lots of instructions plus a download.

First job was to find a javascript interpreter and unittest framework:

  • jsunit – jsunit is no longer actively maintained and has become Jasmine.
  • Jasmine – tries to be a whole way of life, very very young, almost no documentation whatsoever.
  • jstest – no longer maintained and has a fatal version dependancy conflict: jstest requires version 1.6R5 of js.jar but envjs requires 1.7R2 or later…
  • rhinounit – rhino is an implementation of javascript in java. Rhinounit has a really horrible output format that dumps the entire java call-stack when a test fails.
  • xpcshell – is a command-line version of the javascript in firefox and thunderbird. It provides a full javascript browser environment including XMLHttpRequest implementations, so envjs is not needed. Also includes runxpcshelltests.py for executing tests.

So xpcshell it is (believe me – that took much longer to research than you took to read it!).

You need to compile a mozilla thunderbird package on your hudson server to get access to xpcshell. These instructions are boiled down from Simple Thunderbird build. Note that my version does not have debug enabled – this is deliberate and important.

apt-get build-dep thunderbird
apt-get install mercurial libasound2-dev libcurl4-openssl-dev libnotify-dev libiw-dev autoconf2.13
mkdir -pf /opt/kits/thunderbird
cd /opt/kits/thunderbird

# this takes a minute or two
hg clone http://hg.mozilla.org/releases/comm-1.9.2/
cd comm-1.9.2

# this takes several minutes
python client.py checkout

# edit/create .mozconfig and enter
mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/objdir-tb
mk_add_options MOZ_MAKE_FLAGS="-j4"
ac_add_options --enable-application=mail

# this takes ages, 2hrs on an EC2 m1.small! Come back tomorrow...
make -f client.mk

runxpcshelltests.py has a very non-standard output format. I’ve implemented a set of plugins for TAP and jUnit output formats – download runxpcsheltests.tgz – this is a drop-in replacement for /opt/kits/thunderbird/comm-1.9.2/mozilla/testing/xpcshell (if you’ve followed the build instruction above) but you can unpack it anywhere on your hudson server – for example, if you have a source directory then create a directory “scripts” and unpack the tgz file in it. This is also the reason for building mozilla without debug – if debug is enabled then xpcshell prints out various usage information that can’t be trapped and excluded from the formatted test output.

Create a directory test/xpcshell in your source root and create a file all.sh in it containing the following:


D=`dirname $0`

/usr/bin/python2.6 -u /opt/kits/thunderbird/comm-1.9.2/mozilla/config/pythonpath.py\
   --output-type=junit --no-leaklog --no-logfiles\

Now you can add test files to that directory, e.g. test_001_pass.js:

function run_test() {

The do_check_true function effectively checks against “arg == true” so I also created a head_test_funcs.js file in that directory to add more testing functions, e.g.:

function do_check_trueish(item, stack) {
  if (!stack)
    stack = Components.stack.caller;

  var text = item + " a true-ish value?";
  if (item) {
    xpcshell_output.pass(stack, text);
  } else {
    do_throw(text, stack);

The last step is to integrate with hudson. Click on the Configure link in a hudson job. In the Execute Shell section add the line

trunk/test/xpcshell/all.sh > report_xpcshell.xml

In the Post-Build Actions section tick on Publish JUnit test result report and in the Test Report XMLs section enter


If you’re already using junit tests then you may need different output file names to suit.

Groovy!  We can now do automated unit/regression testing on plugin base classes! The next step is to figure out how to provide the xul document environment and perform functional testing like Selenium does for browsers…

NB. I’d really like a Mozilla developer to pick up  runxpcsheltests.tgz and drop it into the current Mozilla system – standardised test output is an item on the mozilla software testing wishlist.

Update: the mozilla team have taken this up as bug 595866.

This page and its contents are copyright © 2020, Ian Rogers. Theme derived from Prav