Writing a unit test for Play websockets - unit-testing

Question

I am working on a Scala + Play application utilizing websockets. I have a simple web socket defined as such:
def indexWS = WebSocket.using[String] { request =>
val out = Enumerator("Hello!")
val in = Iteratee.foreach[String](println).map { _ =>
println("Disconnected")
}
(in,out)
}
I have verified this works using Chrome's console. The issue I'm having is trying to write a unit test for this. Currently I have this:
"send awk for websocket connection" in {
running(FakeApplication()){
val js = route(FakeRequest(GET,"/WS")).get
status(js) must equalTo (OK)
contentType(js) must beSome.which(_ == "text/javascript")
}
}
However, when running my tests in play console, I receive this error, where line 35 corresponds to this line 'val js = route(FakeRequest(GET,"/WS")).get':
NoSuchElementException: None.get (ApplicationSpec.scala:35)
I have not been able to find a good example of unit testing scala/play websockets and am confused on how to properly write this test.

Answer 1

Inspired by answer from bruce-lowe, here is the alternative example with Hookup:
import java.net.URI
import io.backchat.hookup._
import org.specs2.mutable._
import play.api.test._
import scala.collection.mutable.ListBuffer
class ApplicationSpec extends Specification {
"Application" should {
"Test websocket" in new WithServer(port = 9000) {
val hookupClient = new DefaultHookupClient(HookupClientConfig(URI.create("ws://localhost:9000/ws"))) {
val messages = ListBuffer[String]()
def receive = {
case Connected =>
println("Connected")
case Disconnected(_) =>
println("Disconnected")
case JsonMessage(json) =>
println("Json message = " + json)
case TextMessage(text) =>
messages += text
println("Text message = " + text)
}
connect() onSuccess {
case Success => send("Hello Server")
}
}
hookupClient.messages.contains("Hello Client") must beTrue.eventually
}
}
}
The example assumed the websocket actor would reply with "Hello Client" text.
To include the library, add this line to libraryDependencies in build.sbt:
"io.backchat.hookup" %% "hookup" % "0.4.2"

Answer 2

A bit late to answer this one, but in case its useful, here is how I wrote a test for my Websockets. It uses a library from here (https://github.com/TooTallNate/Java-WebSocket)
import org.specs2.mutable._
import play.api.test.Helpers._
import play.api.test._
class ApplicationSpec extends Specification {
"Application" should {
"work" in {
running(TestServer(9000)) {
val clientInteraction = new ClientInteraction()
clientInteraction.client.connectBlocking()
clientInteraction.client.send("Hello Server")
eventually {
clientInteraction.messages.contains("Hello Client")
}
}
}
}
}
And a little utility class to store all messages / events (I'm sure you can enhance it yourself to meet your needs)
import java.net.URI
import org.java_websocket.client.WebSocketClient
import org.java_websocket.drafts.Draft_17
import org.java_websocket.handshake.ServerHandshake
import collection.JavaConversions._
import scala.collection.mutable.ListBuffer
class ClientInteraction {
val messages = ListBuffer[String]()
val client = new WebSocketClient(URI.create("ws://localhost:9000/wsWithActor"),
new Draft_17(), Map("HeaderKey1" -> "HeaderValue1"), 0) {
def onError(p1: Exception) {
println("onError")
}
def onMessage(message: String) {
messages += message
println("onMessage, message = " + message)
}
def onClose(code: Int, reason: String, remote: Boolean) {
println("onClose")
}
def onOpen(handshakedata: ServerHandshake) {
println("onOpen")
}
}
}
This is in my SBT file
libraryDependencies ++= Seq(
ws,
"org.java-websocket" % "Java-WebSocket" % "1.3.0",
"org.specs2" %% "specs2-core" % "3.7" % "test"
)
( There is a sample program here https://github.com/BruceLowe/play-with-websockets with a test )

Answer 3

I think That you can check this site it has a pretty good example about testing websockets with Spec
This a sample from typesafe:
/*
* Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
*/
package play.it.http.websocket
import play.api.test._
import play.api.Application
import scala.concurrent.{Future, Promise}
import play.api.mvc.{Handler, Results, WebSocket}
import play.api.libs.iteratee._
import java.net.URI
import org.jboss.netty.handler.codec.http.websocketx._
import org.specs2.matcher.Matcher
import akka.actor.{ActorRef, PoisonPill, Actor, Props}
import play.mvc.WebSocket.{Out, In}
import play.core.Router.HandlerDef
import java.util.concurrent.atomic.AtomicReference
import org.jboss.netty.buffer.ChannelBuffers
object WebSocketSpec extends PlaySpecification with WsTestClient {
sequential
def withServer[A](webSocket: Application => Handler)(block: => A): A = {
val currentApp = new AtomicReference[FakeApplication]
val app = FakeApplication(
withRoutes = {
case (_, _) => webSocket(currentApp.get())
}
)
currentApp.set(app)
running(TestServer(testServerPort, app))(block)
}
def runWebSocket[A](handler: (Enumerator[WebSocketFrame], Iteratee[WebSocketFrame, _]) => Future[A]): A = {
val innerResult = Promise[A]()
WebSocketClient { client =>
await(client.connect(URI.create("ws://localhost:" + testServerPort + "/stream")) { (in, out) =>
innerResult.completeWith(handler(in, out))
})
}
await(innerResult.future)
}
def textFrame(matcher: Matcher[String]): Matcher[WebSocketFrame] = beLike {
case t: TextWebSocketFrame => t.getText must matcher
}
def closeFrame(status: Int = 1000): Matcher[WebSocketFrame] = beLike {
case close: CloseWebSocketFrame => close.getStatusCode must_== status
}
def binaryBuffer(text: String) = ChannelBuffers.wrappedBuffer(text.getBytes("utf-8"))
/**
* Iteratee getChunks that invokes a callback as soon as it's done.
*/
def getChunks[A](chunks: List[A], onDone: List[A] => _): Iteratee[A, List[A]] = Cont {
case Input.El(c) => getChunks(c :: chunks, onDone)
case Input.EOF =>
val result = chunks.reverse
onDone(result)
Done(result, Input.EOF)
case Input.Empty => getChunks(chunks, onDone)
}
/*
* Shared tests
*/
def allowConsumingMessages(webSocket: Application => Promise[List[String]] => Handler) = {
val consumed = Promise[List[String]]()
withServer(app => webSocket(app)(consumed)) {
val result = runWebSocket { (in, out) =>
Enumerator(new TextWebSocketFrame("a"), new TextWebSocketFrame("b"), new CloseWebSocketFrame(1000, "")) |>>> out
consumed.future
}
result must_== Seq("a", "b")
}
}
def allowSendingMessages(webSocket: Application => List[String] => Handler) = {
withServer(app => webSocket(app)(List("a", "b"))) {
val frames = runWebSocket { (in, out) =>
in |>>> Iteratee.getChunks[WebSocketFrame]
}
frames must contain(exactly(
textFrame(be_==("a")),
textFrame(be_==("b")),
closeFrame()
).inOrder)
}
}
def cleanUpWhenClosed(webSocket: Application => Promise[Boolean] => Handler) = {
val cleanedUp = Promise[Boolean]()
withServer(app => webSocket(app)(cleanedUp)) {
runWebSocket { (in, out) =>
out.run
cleanedUp.future
} must beTrue
}
}
def closeWhenTheConsumerIsDone(webSocket: Application => Handler) = {
withServer(app => webSocket(app)) {
val frames = runWebSocket { (in, out) =>
Enumerator[WebSocketFrame](new TextWebSocketFrame("foo")) |>> out
in |>>> Iteratee.getChunks[WebSocketFrame]
}
frames must contain(exactly(
closeFrame()
))
}
}
def allowRejectingTheWebSocketWithAResult(webSocket: Application => Int => Handler) = {
withServer(app => webSocket(app)(FORBIDDEN)) {
implicit val port = testServerPort
await(wsUrl("/stream").withHeaders(
"Upgrade" -> "websocket",
"Connection" -> "upgrade"
).get()).status must_== FORBIDDEN
}
}
"Plays WebSockets" should {
"allow consuming messages" in allowConsumingMessages { _ => consumed =>
WebSocket.using[String] { req =>
(getChunks[String](Nil, consumed.success _), Enumerator.empty)
}
}
"allow sending messages" in allowSendingMessages { _ => messages =>
WebSocket.using[String] { req =>
(Iteratee.ignore, Enumerator.enumerate(messages) >>> Enumerator.eof)
}
}
"close when the consumer is done" in closeWhenTheConsumerIsDone { _ =>
WebSocket.using[String] { req =>
(Iteratee.head, Enumerator.empty)
}
}
"clean up when closed" in cleanUpWhenClosed { _ => cleanedUp =>
WebSocket.using[String] { req =>
(Iteratee.ignore, Enumerator.empty[String].onDoneEnumerating(cleanedUp.success(true)))
}
}
"allow rejecting a websocket with a result" in allowRejectingTheWebSocketWithAResult { _ => statusCode =>
WebSocket.tryAccept[String] { req =>
Future.successful(Left(Results.Status(statusCode)))
}
}
"allow handling a WebSocket with an actor" in {
"allow consuming messages" in allowConsumingMessages { implicit app => consumed =>
WebSocket.acceptWithActor[String, String] { req => out =>
Props(new Actor() {
var messages = List.empty[String]
def receive = {
case msg: String =>
messages = msg :: messages
}
override def postStop() = {
consumed.success(messages.reverse)
}
})
}
}
"allow sending messages" in allowSendingMessages { implicit app => messages =>
WebSocket.acceptWithActor[String, String] { req => out =>
Props(new Actor() {
messages.foreach { msg =>
out ! msg
}
out ! PoisonPill
def receive = PartialFunction.empty
})
}
}
"close when the consumer is done" in closeWhenTheConsumerIsDone { implicit app =>
WebSocket.acceptWithActor[String, String] { req => out =>
Props(new Actor() {
out ! PoisonPill
def receive = PartialFunction.empty
})
}
}
"clean up when closed" in cleanUpWhenClosed { implicit app => cleanedUp =>
WebSocket.acceptWithActor[String, String] { req => out =>
Props(new Actor() {
def receive = PartialFunction.empty
override def postStop() = {
cleanedUp.success(true)
}
})
}
}
"allow rejecting a websocket with a result" in allowRejectingTheWebSocketWithAResult { implicit app => statusCode =>
WebSocket.tryAcceptWithActor[String, String] { req =>
Future.successful(Left(Results.Status(statusCode)))
}
}
"aggregate text frames" in {
val consumed = Promise[List[String]]()
withServer(app => WebSocket.using[String] { req =>
(getChunks[String](Nil, consumed.success _), Enumerator.empty)
}) {
val result = runWebSocket { (in, out) =>
Enumerator(
new TextWebSocketFrame("first"),
new TextWebSocketFrame(false, 0, "se"),
new ContinuationWebSocketFrame(false, 0, "co"),
new ContinuationWebSocketFrame(true, 0, "nd"),
new TextWebSocketFrame("third"),
new CloseWebSocketFrame(1000, "")) |>>> out
consumed.future
}
result must_== Seq("first", "second", "third")
}
}
"aggregate binary frames" in {
val consumed = Promise[List[Array[Byte]]]()
withServer(app => WebSocket.using[Array[Byte]] { req =>
(getChunks[Array[Byte]](Nil, consumed.success _), Enumerator.empty)
}) {
val result = runWebSocket { (in, out) =>
Enumerator(
new BinaryWebSocketFrame(binaryBuffer("first")),
new BinaryWebSocketFrame(false, 0, binaryBuffer("se")),
new ContinuationWebSocketFrame(false, 0, binaryBuffer("co")),
new ContinuationWebSocketFrame(true, 0, binaryBuffer("nd")),
new BinaryWebSocketFrame(binaryBuffer("third")),
new CloseWebSocketFrame(1000, "")) |>>> out
consumed.future
}
result.map(b => b.toSeq) must_== Seq("first".getBytes("utf-8").toSeq, "second".getBytes("utf-8").toSeq, "third".getBytes("utf-8").toSeq)
}
}
"close the websocket when the buffer limit is exceeded" in {
withServer(app => WebSocket.using[String] { req =>
(Iteratee.ignore, Enumerator.empty)
}) {
val frames = runWebSocket { (in, out) =>
Enumerator[WebSocketFrame](
new TextWebSocketFrame(false, 0, "first frame"),
new ContinuationWebSocketFrame(true, 0, new String(Array.range(1, 65530).map(_ => 'a')))
) |>> out
in |>>> Iteratee.getChunks[WebSocketFrame]
}
frames must contain(exactly(
closeFrame(1009)
))
}
}
}
"allow handling a WebSocket in java" in {
import play.core.Router.HandlerInvokerFactory
import play.core.Router.HandlerInvokerFactory._
import play.mvc.{ WebSocket => JWebSocket, Results => JResults }
import play.libs.F
implicit def toHandler[J <: AnyRef](javaHandler: J)(implicit factory: HandlerInvokerFactory[J]): Handler = {
val invoker = factory.createInvoker(
javaHandler,
new HandlerDef(javaHandler.getClass.getClassLoader, "package", "controller", "method", Nil, "GET", "", "/stream")
)
invoker.call(javaHandler)
}
"allow consuming messages" in allowConsumingMessages { _ => consumed =>
new JWebSocket[String] {
#volatile var messages = List.empty[String]
def onReady(in: In[String], out: Out[String]) = {
in.onMessage(new F.Callback[String] {
def invoke(msg: String) = messages = msg :: messages
})
in.onClose(new F.Callback0 {
def invoke() = consumed.success(messages.reverse)
})
}
}
}
"allow sending messages" in allowSendingMessages { _ => messages =>
new JWebSocket[String] {
def onReady(in: In[String], out: Out[String]) = {
messages.foreach { msg =>
out.write(msg)
}
out.close()
}
}
}
"clean up when closed" in cleanUpWhenClosed { _ => cleanedUp =>
new JWebSocket[String] {
def onReady(in: In[String], out: Out[String]) = {
in.onClose(new F.Callback0 {
def invoke() = cleanedUp.success(true)
})
}
}
}
"allow rejecting a websocket with a result" in allowRejectingTheWebSocketWithAResult { _ => statusCode =>
JWebSocket.reject[String](JResults.status(statusCode))
}
"allow handling a websocket with an actor" in allowSendingMessages { _ => messages =>
JWebSocket.withActor[String](new F.Function[ActorRef, Props]() {
def apply(out: ActorRef) = {
Props(new Actor() {
messages.foreach { msg =>
out ! msg
}
out ! PoisonPill
def receive = PartialFunction.empty
})
}
})
}
}
}
}