title: Testing Right[Seq[MyClass]] and properties
body: <p>I am trying to implement a test with ScalaTest (<code>WordSpecLike</code>, <code>MustMatchers</code>) that verify if an <code>Either[Seq[Error], Seq[Value]]</code> contains one value and if the value has some specific attributes.</p>
  
  <p>Ideally I would like to have something like:</p>
  
  <pre><code>val result:Either[Seq[Error], Seq[Value]] = ...
  result.value must contain { _ have (
    'prop ("value")
  )}
  </code></pre>
  
  <p>But this does not compile and I have no clue on how to achieve this kind of matching.</p>
  
  <p>Is there documentation on deep tests or some best practices for that?</p>