Akka HTTP: Examples of HttpRequest and HttpResponse model

HttpRequestResponseSampleRoutes.scala

package com.tutorial.sample

import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport
import akka.http.scaladsl.model.HttpCharsets._
import akka.http.scaladsl.model.HttpMethods.{POST, PUT}
import akka.http.scaladsl.model.HttpProtocols.`HTTP/1.0`
import akka.http.scaladsl.model.MediaTypes.`text/plain`
import akka.http.scaladsl.model.headers.BasicHttpCredentials
import akka.http.scaladsl.model.{StatusCodes, headers => mHeaders, _}
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.server.Route
import akka.http.scaladsl.server.directives.Credentials
import akka.http.scaladsl.server.directives.MethodDirectives.{get, post}
import akka.http.scaladsl.server.directives.RouteDirectives.complete
import akka.http.scaladsl.testkit.ScalatestRouteTest
import akka.util.ByteString
import org.scalatest.{Matchers, WordSpec}
import spray.json.DefaultJsonProtocol

trait HttpRequestResponseSampleRoutes extends SprayJsonSupport {

  import DefaultJsonProtocol._

  var users: List[String] = Nil

  lazy val userRoutes: Route =
    pathPrefix("users") {
      pathEnd {
        concat(
          get {
            complete(users)
          },
          post {
            entity(as[String]) { user =>
              users ::= user
              complete((StatusCodes.Created, user))
            }
          },
          put {
            authenticateBasic(realm = "secure site", myUserPassAuthenticator) { userName =>
              entity(as[String]) { user =>
                users ::= user
                complete((StatusCodes.Created, user))
              }
            }
          }
        )
      }
    }

  def myUserPassAuthenticator(credentials: Credentials): Option[String] =
    credentials match {
      case p@Credentials.Provided(id) if p.verify("pass") => Some(id)
      case _ => None
    }

}

class HttpRequestResponseSampleRoutesSpec extends WordSpec with Matchers with ScalatestRouteTest
  with HttpRequestResponseSampleRoutes {

  lazy val routes = userRoutes

  "UserRoutes" should {
    "return no users if no present (GET /users)" in {
      val request = HttpRequest(uri = "/users")

      request ~> routes ~> check {
        response should ===(HttpResponse(StatusCodes.OK,List(),HttpEntity(ContentType(MediaTypes.`application/json`), """[]"""),HttpProtocols.`HTTP/1.1`))

        status should ===(StatusCodes.OK)

        entityAs[String] should ===("""[]""")
      }
    }

    "be able to add users (POST /users)" in {
      val request = HttpRequest(POST, uri = "/users", entity = ByteString("User1"))

      request ~> routes ~> check {
        status should ===(StatusCodes.Created)

        entityAs[String] should ===("""User1""")
      }
    }

    "be able to add users (PUT /users) with authentication" in {
      val request = HttpRequest(
        PUT,
        uri = "/users",
        entity = HttpEntity(`text/plain` withCharset `UTF-8`, ByteString("User2")),
        headers = List(mHeaders.Allow(POST, PUT), mHeaders.Authorization(BasicHttpCredentials("user", "pass"))),
        protocol = `HTTP/1.0`)

      request ~> routes ~> check {
        status should ===(StatusCodes.Created)

        entityAs[String] should ===("""User2""")
      }
    }
  }
}

Useful and relates to chapter 4 of your book, which is enjoyable and useful.

Note that your line 9 renaming of import headers to mHeaders makes it a little difficult to track in the book without this gist. That's why I had to come here!