This task will create a folder (doc/coverage) then run all of your tests and produce HTML with code coverage information in that folder. If you are on a mac it will even open the index.html file up for you automatically
namespace :test do
desc "Generate code coverage with rcov"
task :coverage do
rm_f "doc/coverage/coverage.data"
rm_f "doc/coverage"
mkdir "doc/coverage"
rcov = %(rcov --rails --aggregate doc/coverage/coverage.data --text-summary -Ilib --html -o doc/coverage test/**/*_test.rb)
system rcov
system "open doc/coverage/index.html" if PLATFORM['darwin']
end
end