You know all those other Macs you have lying around the house sitting idle all the time? Well I have some great news. You can finally put those freeloaders to work! With specjour ( http://github.com/sandro/specjour ), you can distribute your test suite across all the cores on your network!

It uses bonjour to communicate and can support multiple projects simultaneously. As long as the machine has the dependencies required for the test suite (gems and unix packages), it can participate in the testing goodness. The current contents of your project get rsync’d to the managers, so they will always match your local changes.

You get started by installing it into your Rails project. First, setup the dependency in the test group of your Gemfile.

group :test do
  gem ‘specjour’, ‘0.2.5’
end

Now make a small update to your config/database.yml. A number needs to be appended to the test database name to support multiple simultaneous tests for the same project. It matches that used by parallel_test, so if you used that previously you should be all set.

test:
  database: blog_test<%=ENV['TEST_ENV_NUMBER']%>

To fire up a local manager, open up a new terminal tab and simply run:

specjour

To execute your test suite, run:

rake specjour

It will automatically determine the number of cores on your machine and utilize them all. With it working on your main dev machine, you are all ready to get the real magic started!

SSH to another machine on your network that you want to run the tests for you. Make sure you install the dependencies your project needs (mysql, imagemagick, mongodb, etc) and all the gems it needs. Run specjour just like you did on the first machine.

Back on your dev machine, run rake specjour again. This time you will see more workers in the list and your suite should run considerably faster.

There are additional options you can pass to specify project names to listen for and how many cores to use, but for most people the defaults should work fine. Those options are passed to the manager and would look something like this:

specjour --workers 4 --projects blinq,workbeast

We have seen drastic improvements in the execution times of long running test suites using specjour. But even if your suite only takes a couple of minutes to run and you only have one machine, you should still seen a nice performance gain.