display_case testing with rspec

gistfile1.rb

# app/models/post.rb
class Post < ActiveRecord::Base
  has_many :comments
end

# app/exhibits/post_exhibit.rb
class PostExhibit< DisplayCase::Exhibit

  def self.applicable_to?(object)
    object_is_any_of?(object, Post)
  end

  exhibit_query :comments
end

# spec/exhibits/post_exhibit_spec.rb
require 'spec_helper'
require 'ostruct'

describe PostExhibit do
  subject        { PostExhibit.new(post, context) }

  let(:post)     { OpenStruct.new(:comments => comments) }
  let(:comments) { Object.new }
  let(:context)  { Object.new }

  it 'exhibits its comments' do
    exhibited_comments = Object.new
    subject.should_receive(:exhibit).with(comments).and_return(exhibited_comments)
    subject.comments.should equal(exhibited_comments)
  end

end