Jekyll testing on a budget (rake-flavored)

Rakefile

desc 'Test site output for Liquid template errors'
task :test => :build do
  errors = `grep --exclude Rakefile -R 'Liquid error:' _site`
  if errors.nil? || errors.empty?
    puts "No errors"
  else
    puts "Errors:"
    puts errors.inspect
    exit 1
  end
end