title: Get nested attributes associated with a model
body: <p>I am trying to write one of the test case where i am looking for a cleaner way of fetching nested attributes associated with the model</p>
  
  <p>For eg</p>
  
  <pre><code>class Category &lt; ActiveRecord::Base
  
  accepts_nested_attributes_for :devices, :books
  
  #other association and code is not written here
  
  end
  </code></pre>
  
  <p><strong>I expect</strong></p>
  
  <pre><code>$ Category.get_nested_attributes #this is a dummy method
  $ ["devices","books"] #this is the return i expect
  </code></pre>
  
  <p>Is there any already existing helper method? If yes please let me know. :)</p>
  
  <p>Thanks</p>