I’ve played with Ruby, but not with Rails. Upon being handed a Rails project to run with the CI Server I was a little thrown and confused. Here’s the solution we came to with some greatly appreciated help from @fearoffish to get Hudson to run the tests on a ruby project:

1. check out the project source code.
2. Download and install Ruby (if you’re on windows try the one click installer) and install rubygems too.
3. try to figure out which database the developer has used (ask them! or check the config/database.yml file adapter value) – usually sqlite3 or mysql (after install use the detailed configuration and follow the defaults remembering to set your root password!). I used mysql and these instructions
4. run:

gem install rails

5. in your source code there is a config folder with an automagically created “database.yml” file. Edit this to only show the “test” section as we’re only going to be running rake tests.

6. 

7. run

gem install mysql

8. If you’re on a windows box you’ll see a few errors, in which case you need to (courtesy of the MySQL forum post below) download http://instantrails.rubyforge.org/svn/trunk/InstantRails-win/InstantRails/mysql/bin/libmySQL.dll and save it to your Ruby bin directory.
9. now you’ll need to create the meh_test database:

   rake db:create RAILS_ENV=test

   
   rake db:migrate RAILS_ENV=test
   

10. go to the root directory of your source code and run:

    rake

11. this should run all your tests.
12. restart Hudson
13. in Hudson, configure the project to check out the code and the other usual gubbins, but for the build step select “Execute Windows batch command” and in the text write:

rake RAILS_ENV=test

14. To get the bloody thing running:

 Ruby script/sever –e production –d

-e to specify the db (was using development one by default which we didn’t have a definition for in conf/database.yml so it complained)

-d to daemonize it so it doesn’t just run on the command line but goes off to run in the background