Rakefile (shoulda + rcov)

Rakefile

## add this to test/test_helper.rb
require 'shoulda/rails'

## add this to Rakefile
require 'shoulda/tasks'
namespace :test do
  desc 'Measures test coverage'
  task :coverage do
    rm_f "coverage"
    rm_f "coverage.data"
    rcov = "rcov -Itest --rails --aggregate coverage.data -T -x \" rubygems/*,/Library/Ruby/Site/*,gems/*,rcov*\""
    system("#{rcov} --no-html test/unit/*_test.rb test/unit/helpers/*_test.rb")
    system("#{rcov} --no-html test/functional/*_test.rb")
    system("#{rcov} --html test/integration/*_test.rb") unless Dir.glob("test/integration/*_test.rb").empty?
    system("open coverage/index.html") if PLATFORM['darwin']
  end
end

## usage
rake test:coverage