556012b7ee
main work by @drewhk with contributions from @2m and @rkuhn This work uncovered many well-hidden bugs in existing Stages, in particular StatefulStage. These were hidden by the behavior of OneBoundedInterpreter that normally behaves more orderly than it guarantees in general, especially with respect to the timeliness of delivery of upstream termination signals; the bugs were then that internal state was not flushed when onComplete arrived “too early”.
111 lines
2.7 KiB
Scala
111 lines
2.7 KiB
Scala
/**
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* Copyright (C) 2015 Typesafe Inc. <http://www.typesafe.com>
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*/
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package docs.stream
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import akka.stream._
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import akka.stream.scaladsl._
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import akka.stream.testkit._
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import akka.stream.testkit.scaladsl._
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import scala.util.Random
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import scala.math._
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import scala.concurrent.Await
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import scala.concurrent.duration._
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import scala.collection.immutable
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import akka.testkit.TestLatch
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class RateTransformationDocSpec extends AkkaSpec {
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type Seq[+A] = immutable.Seq[A]
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val Seq = immutable.Seq
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implicit val mat = ActorMaterializer()
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"conflate should summarize" in {
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//#conflate-summarize
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val statsFlow = Flow[Double]
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.conflate(Seq(_))(_ :+ _)
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.map { s =>
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val μ = s.sum / s.size
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val se = s.map(x => pow(x - μ, 2))
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val σ = sqrt(se.sum / se.size)
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(σ, μ, s.size)
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}
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//#conflate-summarize
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val fut = Source(() => Iterator.continually(Random.nextGaussian))
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.via(statsFlow)
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.grouped(10)
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.runWith(Sink.head)
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Await.result(fut, 100.millis)
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}
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"conflate should sample" in {
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//#conflate-sample
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val p = 0.01
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val sampleFlow = Flow[Double]
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.conflate(Seq(_)) {
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case (acc, elem) if Random.nextDouble < p => acc :+ elem
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case (acc, _) => acc
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}
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.mapConcat(identity)
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//#conflate-sample
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val fut = Source(1 to 1000)
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.map(_.toDouble)
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.via(sampleFlow)
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.runWith(Sink.fold(Seq.empty[Double])(_ :+ _))
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val count = Await.result(fut, 1000.millis).size
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}
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"expand should repeat last" in {
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//#expand-last
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val lastFlow = Flow[Double]
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.expand(identity)(s => (s, s))
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//#expand-last
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val (probe, fut) = TestSource.probe[Double]
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.via(lastFlow)
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.grouped(10)
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.toMat(Sink.head)(Keep.both)
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.run()
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probe.sendNext(1.0)
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val expanded = Await.result(fut, 100.millis)
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expanded.size shouldBe 10
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expanded.sum shouldBe 10
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}
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"expand should track drift" in {
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//#expand-drift
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val driftFlow = Flow[Double]
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.expand((_, 0)) {
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case (lastElement, drift) => ((lastElement, drift), (lastElement, drift + 1))
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}
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//#expand-drift
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val latch = TestLatch(2)
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val realDriftFlow = Flow[Double]
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.expand(d => { latch.countDown(); (d, 0) }) {
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case (lastElement, drift) => ((lastElement, drift), (lastElement, drift + 1))
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}
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val (pub, sub) = TestSource.probe[Double]
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.via(realDriftFlow)
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.toMat(TestSink.probe[(Double, Int)])(Keep.both)
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.run()
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sub.request(1)
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pub.sendNext(1.0)
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sub.expectNext((1.0, 0))
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sub.requestNext((1.0, 1))
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sub.requestNext((1.0, 2))
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pub.sendNext(2.0)
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Await.ready(latch, 1.second)
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sub.requestNext((2.0, 0))
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}
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}
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