Route test never finishes waiting on CountDownLatch

[asarkar]

c.f. https://stackoverflow.com/questions/47636871/why-does-this-akka-http-route-test-never-complete-successfully

Some debugging shows that the following code in RouteTestResultComponent is causing the problem

private[testkit] def handleResult(rr: RouteResult): Unit =
 synchronized {
   if (result.isEmpty) {
     result = rr match {
       case RouteResult.Complete(response)   ⇒ Some(Right(response))
       case RouteResult.Rejected(rejections) ⇒ Some(Left(RejectionHandler.applyTransformations(rejections)))
     }
     latch.countDown()
   } else failTest("Route completed/rejected more than once")
 }

private[testkit] def awaitResult: this.type = {
 latch.await(timeout.toMillis, MILLISECONDS)
 this
}

I'm not sure yet why, but the latch is never decremented causing the request to eventually time out within awaitResult

[ktoso]

Please refrain from cross posting like this. Issues are for issues and not general questions.
The question was answered on stack overflow already: https://stackoverflow.com/questions/47636871/why-does-this-akka-http-route-test-never-complete-successfully

You should use probes for each of your tests which were explained in the Stack Overflow answewr

[asarkar]

@ktoso If you looked at the SO thread, you'd see that I clearly mentioned probes are not the issue. Just because someone made an attempt doesn't mean it's the right answer. And as far as cross-posting goes, I did put the SO link, didn't I?
I believe this is an issue, hence I'm raising it here. Can you disprove that?

[jonas]

I don't know if it is related but when I run the complete Akka HTTP test suite I never get back the sbt prompt. I'm assuming the tests hang somewhere but I didn't investigate.

[asarkar]

@jonas I didn’t find any tests for completeWith directive. Do you’ve any?

[jonas]

There are several test in the documentation examples under docs/src/test.

[asarkar]

I searched the whole codebase, and there isn't a single instance of completeWith used with an Actor. Not in main code, or in tests.

[asarkar]

@jonas I got it working myself and have a theory that I'll appreciate if you can comment on.

"Routes" should "respond to get apps request" in {
  testProbe.setAutoPilot((_: ActorRef, msg: Any) => {
    msg match {
      case GetAppsRequest(callback) => callback(List("test")); TestActor.KeepRunning
      case _ => TestActor.NoAutoPilot
    }
  })

  Get("/apps") ~> handler ~> check {
    entityAs[List[String]] should contain("test")
  }
}

My theory is that putting TestProbe inside check hangs forever probably because it creates a deadlock; test waits for callback to be called, and callback isn't called until the body is executed.

Using autopilot sets up an "expectation" that can be fulfilled later thus avoiding the deadlock.