olor:#66d9ef">_</span><span style="color:#f92672">.</span>qty<span style="color:#f92672">).</span>sum
</code></pre></div><p>A test suite that needs state must implement <code>State[T]</code>, where <code>T</code> is the type carrying
the state you need. There are <em>no requirements</em> on the type <code>T</code> or its signature, you are free
to use whatever type you want. We prefer to use <code>case class</code> as they are immutable, but any
type will do.</p>
<p>The <em>root state</em> gets created in t