title: Rails "assert" undefined method '+'
body: <p>I think this is a very basic question...Why isn't the <code>assert</code> method working in this simple example?</p>
  
  <pre><code>assert true
  </code></pre>
  
  <p>I get the following error message: </p>
  
  <pre><code>NoMethodError Exception: undefined method `+' for nil:NilClass
  </code></pre>
  
  <p>This is in rails 4.2.1. </p>
  
  <p>Edit: This is literally the whole block of code. All I do is enter the rails console and type assert true.</p>