e x p r e s s i c a

To use your migrations for preparing test database create a file testdb.rake
in the directory lib/tasks.
Now add the following code in the lib/tasks/testdb.rake file…

module Rake
  module TaskManager
    def redefine_task(task_class, args, &block)
      task_name, deps = resolve_args(args)
      task_name = task_class.scope_name(@scope, task_name)
      deps = [deps] unless deps.respond_to?(:to_ary)
      deps = deps.collect {|d| d.to_s }
      task = @tasks[task_name.to_s] = task_class.new(task_name, self)
      task.application = self
      task.add_comment(@last_comment)
      @last_comment = nil
      task.enhance(deps, &block)
      task
    end
  end
  class Task
    class << self
      def redefine_task(args, &block)
        Rake.application.redefine_task(self, args, &block)
      end
    end
  end
end

def redefine_task(args, &block)
  Rake::Task.redefine_task(args, &block)
end

namespace :db do
  namespace :test do

    desc ‘Prepare the test database and migrate schema’
    redefine_task :prepare => :environment do
      Rake::Task['db:test:migrate_schema'].invoke
    end

    desc ‘Use the migrations to create the test database’
    task :migrate_schema => ‘db:test:purge’ do
      ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations['test'])
      ActiveRecord::Migrator.migrate(”db/migrate/”)
    end

  end
end

To prepare the test database from migrations run this command
$ rake db:test:migrate_schema

To add a rake task to the rails application which removes all the image and audio files created by captcha, create a file named remove_captcha_files.rake in the lib/tasks directory.
Add the following code to the lib/tasks/remove_captcha_files.rake file…

desc "Remove captcha images and audio files"
task :remove_captcha_files do
  image_path = "#{RAILS_ROOT}/public/images/captcha/"
  audio_path = "#{RAILS_ROOT}/public/captcha_audio/"
  Dir.foreach(image_path){|file| File.delete(image_path+file) if (/^.*.jpg$/).match(file)} if File.exist?(image_path)
  Dir.foreach(audio_path){|file| File.delete(audio_path+file) if (/^.*.wav$/).match(file)} if File.exist?(audio_path)
  puts "Captcha files removed."
end

You can confirm that task is added to your app by running
rake –task

To remove all the files created by captcha, simply run the command
rake remove_captcha_files
from the command line from your application root.
To better view the code visit here