Guardfile.rb

guard 'shell' do
  watch(/(.*)/) do |m|
    if system("git ls-files --exclude-standard -d -o -m | egrep '.' > /dev/null")
      test_output = Tempfile.new('guard_commit_test_output')
      test_output.close
      tests_passing = system("rake 2>&1 >> #{test_output.path}")

      commit_message = Tempfile.new('guard_commit_message')
      commit_message.write("WIP: #{m[0]} (Tests: #{tests_passing ? 'passing' : 'failing'})\n\n")
      commit_message.write(File.read test_output.path)
      commit_message.close

      system('git add -A')
      system("git commit -F #{commit_message.path}")

      test_output.unlink
      commit_message.unlink
    end
  end
end