The following syntax should work using this plugin:

<pre><code class="hljs javascript"><span class="hljs-keyword">var</span> myCodeBlock = <span class="hljs-string">'```'</span> +
  <span class="hljs-string">'some-code'</span> +
  <span class="hljs-string">'```'</span>;
done();</code></pre>

And be a single js code block