I\'ve just started testing out the Akka HTTP Request-Level Client-Side API (Future-Based). One thing I\'ve been struggling to figure out is how to write a unit test for this. Is
I think in general terms you've already hit on the fact that the best approach is to mock the response. In Scala, this can be done using Scala Mock http://scalamock.org/
If you arrange your code so that your instance of akka.http.scaladsl.HttpExt
is dependency injected into the code which uses it (e.g. as a constructor parameter), then during testing you can inject an instance of mock[HttpExt]
rather than one built using the Http
apply method.
EDIT: I guess this was voted down for not being specific enough. Here is how I would structure the mocking of your scenario. It is made a little more complicated by all the implicitis.
Code in main
:
import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.{Uri, HttpResponse, HttpRequest}
import akka.http.scaladsl.unmarshalling.Unmarshal
import akka.stream.ActorMaterializer
import scala.concurrent.{ExecutionContext, Future}
trait S3BucketTrait {
type HttpResponder = HttpRequest => Future[HttpResponse]
def responder: HttpResponder
implicit def actorSystem: ActorSystem
implicit def actorMaterializer: ActorMaterializer
implicit def ec: ExecutionContext
def sampleTextFile(uri: Uri): Future[String] = {
val responseF = responder(HttpRequest(uri = uri))
responseF.flatMap { response => Unmarshal(response.entity).to[String] }
}
}
class S3Bucket(implicit val actorSystem: ActorSystem, val actorMaterializer: ActorMaterializer) extends S3BucketTrait {
override val ec: ExecutionContext = actorSystem.dispatcher
override def responder = Http().singleRequest(_)
}
Code in test
:
import akka.actor.ActorSystem
import akka.http.scaladsl.model._
import akka.stream.ActorMaterializer
import akka.testkit.TestKit
import org.scalatest.{BeforeAndAfterAll, WordSpecLike, Matchers}
import org.scalamock.scalatest.MockFactory
import scala.concurrent._
import scala.concurrent.duration._
import scala.concurrent.Future
class S3BucketSpec extends TestKit(ActorSystem("S3BucketSpec"))
with WordSpecLike with Matchers with MockFactory with BeforeAndAfterAll {
class MockS3Bucket(reqRespPairs: Seq[(Uri, String)]) extends S3BucketTrait{
override implicit val actorSystem = system
override implicit val ec = actorSystem.dispatcher
override implicit val actorMaterializer = ActorMaterializer()(system)
val mock = mockFunction[HttpRequest, Future[HttpResponse]]
override val responder: HttpResponder = mock
reqRespPairs.foreach{
case (uri, respString) =>
val req = HttpRequest(HttpMethods.GET, uri)
val resp = HttpResponse(status = StatusCodes.OK, entity = respString)
mock.expects(req).returning(Future.successful(resp))
}
}
"S3Bucket" should {
"Marshall responses to Strings" in {
val mock = new MockS3Bucket(Seq((Uri("http://example.com/1"), "Response 1"), (Uri("http://example.com/2"), "Response 2")))
Await.result(mock.sampleTextFile("http://example.com/1"), 1 second) should be ("Response 1")
Await.result(mock.sampleTextFile("http://example.com/2"), 1 second) should be ("Response 2")
}
}
override def afterAll(): Unit = {
val termination = system.terminate()
Await.ready(termination, Duration.Inf)
}
}
build.sbt
dependencies:
libraryDependencies += "com.typesafe.akka" % "akka-http-experimental_2.11" % "2.0.1"
libraryDependencies += "org.scalamock" %% "scalamock-scalatest-support" % "3.2" % "test"
libraryDependencies += "org.scalatest" % "scalatest_2.11" % "2.2.6"
libraryDependencies += "com.typesafe.akka" % "akka-testkit_2.11" % "2.4.1"