title: Set order of RSpec tests
body: <p>I'm building a test suite to teach OOP. I want the files in my <code>spec/lib</code> folder to be executed in a specific order.</p>
  <p>I would like to define an array of class names, and their test suite would be executed in order. For example:</p>
  <pre><code>spec_order = %w(
    FirstClass
    SecondClass
    ThirdClass
  )
  </code></pre>
  <p>How might I accomplish this?</p>