Running rake test on local before deploying using capistrano

deploy.rb

namespace :deploy do

  desc "Runs test before deploying, can't deploy unless they pass"
  task :run_tests do

    puts "--> Running tests, please wait ..."
    test_log = "log/capistrano.log"
    unless system "bundle exec rake > #{test_log} 2>&1" #' > /dev/null'
      puts "--> Tests failed. Run `cat #{test_log}` to see what went wrong."
      exit
    else
      puts "--> Tests passed"
      system "rm #{test_log}"
    end

  end

end

before :deploy, "deploy:run_tests"