Ruby on Rails: Switch from test_unit to rspec

In your config/application.rb file :

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

Now when you run your generators (example rails generate scaffold post), you get rspec test files. Remember to restart your server. For more information on generators see:

RailsCasts #216 Generators in Rails 3

If you really want to use the integration_test generator you'll need to specifically modify the command:

rails g integration_test named --integration-tool=rspec

Working with Rails 3.2.8 and rspec-rails 2.11.4, I discovered that my problem was in my Gemfile. I had rspec-rails in the :test group but not the :development group. Since Rails defaults to running in development mode (including when you're running generate), rspec-rails has to be in your :development group for it to hook into the generators. Once I had that in place, everything worked fine.

As of Rails 3.2.12, follow these steps in order

rails new app_name --skip-test-unit

Add rspec-rails to your Gemfile in the development, test group

group :development, :test do
  gem 'rspec-rails'
end

Run bundle install

Run the generator

rails generate rspec:install

... and cleanup your existing test directory:

rm -Rf $RAILS_ROOT/test