Play WS POST with Iteratee to Akka HTTP Server

AkkaHttpWebServer

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.HttpEntity
import akka.http.scaladsl.server.Directives._
import akka.stream.ActorMaterializer

class TestWebServer(testSystem: ActorSystem){

  implicit val system = testSystem
  implicit val materialize = ActorMaterializer()
  implicit val executionContext = system.dispatcher

  val port = 8080
  val route =
    path("test") {
      post {
        complete(HttpEntity("POST Ok"))
      } ~
      get {
        complete(HttpEntity("GET Ok"))
      }
    }
  val bindingFuture = Http().bindAndHandle(route, "localhost", port)

  def shutdown(): Unit = bindingFuture.flatMap(_.unbind())
}

PlayClient.scala

      implicit val httpClient = NingWSClient()
      implicit val execution = play.api.libs.concurrent.Execution.Implicits.defaultContext
      val f = WS.clientUrl("http://localhost:8080/test")
        .withMethod("POST")
        .stream().flatMap {
        case (resp, body) =>
          val it = Iteratee.fold[Array[Byte],Seq[Byte]](Seq.empty[Byte]) { (stream, bytes) =>
            stream ++ bytes
          }

          (body |>>> it).map {
            case stream =>
              new String(stream.toArray, "UTF-8")
          }
      }

      val r = Await.result(f, 1.second)
      assert(r == "POST Ok")