Rails

Use rspec and rspec-rails gems

See config.gem

Install rspec and rspec-rails plugins for Rails >= 2.1.0

ruby script/plugin install git://github.com/dchelimsky/rspec.git -r 'refs/tags/1.2.7'
ruby script/plugin install git://github.com/dchelimsky/rspec-rails.git -r 'refs/tags/1.2.7.1'
ruby script/generate rspec

Install rspec and rspec-rails plugins for Rails < 2.1.0

cd vendor/plugins
git clone git://github.com/dchelimsky/rspec.git
git clone git://github.com/dchelimsky/rspec-rails.git
cd rspec
git checkout 1.1.8
cd ../rspec-rails
git checkout 1.1.8
cd ..
rm -rf rspec/.git
rm -rf rspec-rails/.git
cd ../../
ruby script/generate rspec