There are lots of perfectly useful tutorials on getting started with Rails, so I won’t go into a lot of detail there. I assume that you already have Ruby and Rails installed; as of the time of this writing, I’m using versions 1.9.2 and 3.0.4 respectively.

Set up Rails

Create a new Rails application:

  $ rails new bdd
  $ cd bdd
  $ git init .
  $ git commit -a -m 'Initial import'

Now run rails server and point your browser at http://localhost:3000/ to make sure that it runs.

Edit Gemfile and add these lines to the bottom:

  group :development, :test do
    gem "rspec-rails", "~> 2.4"
    gem 'capybara'
    gem 'database_cleaner'
    gem 'cucumber-rails'
    gem 'cucumber', '>= 0.10.0'
    gem 'spork'
    gem 'launchy'
  end

Then run bundle install to update gems. Run rails server again as a sanity check.

Set up RSpec

Install RSpec into the application:

  $ rails generate rspec:install

Configure the application to create specs instead of unit tests. Edit config/application.rb and add to the bottom of the class definition:

  config.generators do | g |
    g.test_framework :rspec
  end

Set up Cucumber

Install Cucumber into the application:

  $ rails generate cucumber:install --rspec --capybara

Test it out

First, generate the database:

  $ rake db:migrate

Make sure RSpec doesn’t choke:

  $ rake spec
  No examples matching ./spec/**/*_spec.rb could be found

And that Cucumber doesn’t, either:

  $ rake cucumber
  bundle exec ...
  Using the default profile...
  0 scenarios
  0 steps
  0m0.000s

Now we’re ready to start writing features and specs.