Using ApiRequest (https://gist.github.com/glowacki-dev/33135500ac72ab53f7a56d114c924db1) as test subject

posts_spec.rb

require 'acceptance_helper'

resource 'Posts' do
  explanation 'Posts are entities holding some text information.
               They can be created and seen by anyone'

  post '/posts' do
    # ... Same as before ...
    
    subject do
      ApiRequest.new
    end

    include_examples 'api_requests',
                     'Creating a post',
                     'You can create a post by sending its body text and an optional title'
  end
end