!str #16039 Remove old scaladsl, rename scaladsl2

* and impl2, testkit2
* keeping io2 for now

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowAppendSpec.scala

@@ -0,0 +1,62 @@
+/**
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.stream.scaladsl
+
+import akka.actor.ActorSystem
+import akka.stream.FlowMaterializer
+import akka.stream.MaterializerSettings
+import akka.stream.testkit.{ AkkaSpec, StreamTestKit }
+import org.reactivestreams.Subscriber
+import org.scalatest.Matchers
+
+class FlowAppendSpec extends AkkaSpec with River {
+
+  val settings = MaterializerSettings(system)
+  implicit val materializer = FlowMaterializer(settings)
+
+  "Flow" should {
+    "append Flow" in riverOf[String] { subscriber ⇒
+      val flow = Flow[Int].connect(otherFlow)
+      Source(elements).connect(flow).connect(Sink(subscriber)).run()
+    }
+
+    "append Sink" in riverOf[String] { subscriber ⇒
+      val sink = Flow[Int].connect(otherFlow.connect(Sink(subscriber)))
+      Source(elements).connect(sink).run()
+    }
+  }
+
+  "Source" should {
+    "append Flow" in riverOf[String] { subscriber ⇒
+      Source(elements)
+        .connect(otherFlow)
+        .connect(Sink(subscriber)).run()
+    }
+
+    "append Sink" in riverOf[String] { subscriber ⇒
+      Source(elements)
+        .connect(otherFlow.connect(Sink(subscriber)))
+        .run()
+    }
+  }
+
+}
+
+trait River { self: Matchers ⇒
+
+  val elements = (1 to 10)
+  val otherFlow = Flow[Int].map(_.toString)
+
+  def riverOf[T](flowConstructor: Subscriber[T] ⇒ Unit)(implicit system: ActorSystem) = {
+    val subscriber = StreamTestKit.SubscriberProbe[T]()
+
+    flowConstructor(subscriber)
+
+    val subscription = subscriber.expectSubscription()
+    subscription.request(elements.size)
+    subscriber.probe.receiveN(elements.size) should be(elements.map(_.toString).map(StreamTestKit.OnNext(_)))
+    subscription.request(1)
+    subscriber.expectComplete()
+  }
+}