acts_as_commentable.rb

module ActsAsCommentable
  module Shoulda
    def should_be_commentable
      should_have_many :comments
      should_have_class_methods :find_comments_for, :find_comments_by_user
      should_have_instance_methods :add_comment, :comments_ordered_by_submitted
    end
  end
end

Test::Unit::TestCase.extend(ActsAsCommentable::Shoulda)

acts_as_taggable.rb

module ActsAsTaggableOn
  module Shoulda
    def should_be_taggable
      should_be_taggable_on(:tags)
    end

    def should_be_taggable_on(*args)
      klass = self.name.gsub(/Test$/, '').constantize
      
      args.flatten! if args
      args.compact! if args
      for tag_type in args
        tag_type = tag_type.to_s
      
        context "Class #{klass.name} with tag #{tag_type}" do
          should_have_class_methods :taggable?, "caching_#{tag_type.singularize}_list?".to_sym, "#{tag_type.singularize}_counts".to_sym
          should_have_instance_methods "#{tag_type.singularize}_list".to_sym, "#{tag_type.singularize}_list=".to_sym, "#{tag_type.singularize}_counts".to_sym, "#{tag_type}_from".to_sym, "find_related_#{tag_type}".to_sym, "find_related_on_#{tag_type}".to_sym, "find_related_#{tag_type}_for".to_sym

          base_assoc = "#{tag_type.singularize}_taggings".to_sym
          should_have_many base_assoc
          should_have_many tag_type.to_sym, :through => base_assoc
        end
        
      end      
    end
  end
end

Test::Unit::TestCase.extend(ActsAsTaggableOn::Shoulda)

salty_slugs.rb

module SaltySlugs
  module Shoulda
    def should_be_slugged(*args)
      klass = self.name.gsub(/Test$/, '').constantize
      
      options = args.extract_options!
      slug_column = options[:slug_column] || 'slug'
      source_column = options[:source_column] || 'title'
      
      context "Class #{klass.name} with a slug" do
        should_have_db_column slug_column
        should_have_instance_methods source_column
      end
    end
  end
end

Test::Unit::TestCase.extend(SaltySlugs::Shoulda)