title: Akka Http / Circe Decode Result
body: <p>I apologize if I'm missing something simple, but I'm trying to use Akka HTTP with Circe (using the <a href="https://github.com/hseeberger/akka-http-json" rel="nofollow noreferrer">akka-http-json</a> Circe module). I'm trying to retrieve the results of a GET call in a ScalaTest which mixes in the <code>ErrorAccumulatingCirceSupport</code> trait.  The call goes through successfully, but I'm unable to unmarshal the response...It's a pretty simple test, but I'm just not sure how to unmarshal the results into a list of domain objects, eg:</p>
  
  <pre class="lang-scala prettyprint-override"><code>    Get("/path/to/getfoos").withHeaders(auth) ~&gt; Route.seal(service.route) ~&gt; check {
        import io.circe.generic.auto._
        status shouldEqual StatusCodes.OK
        contentType should ===(ContentTypes.`application/json`)
        val reports = responseAs[List[Foo]]
        reports.size shouldBe 1
     }
  </code></pre>
  
  <p>The error I'm getting is:</p>
  
  <pre><code>Could not unmarshal response to type 'scala.collection.immutable.List' for `responseAs` assertion: de.heikoseeberger.akkahttpcirce.ErrorAccumulatingCirceSupport$DecodingFailures: DecodingFailure at [0]: CNil
  </code></pre>
  
  <p>If anyone can point out what I'm dong wrong I would very much appreciate the help!</p>
  
  <p>Thanks!</p>