title: What's this _n_ Ruby koans?
body: <p>I'm trying out Ruby koans and found some tests using this <code>_n_</code> , never seen it before what is it and how do I use it? </p>
  
  <p>Example:</p>
  
  <pre><code>def test_objects_have_methods
             fido = Dog.new
             assert fido.methods.size &gt; _n_
  end
  </code></pre>
  
  <p>// John</p>