move code to src/test

* so that it compiles and tests pass
* fix some additional snip references in getting started

akka-docs/src/main/scala/docs/stream/cookbook/RecipeDigest.scala

@@ -1,72 +0,0 @@
-package docs.stream.cookbook
-
-import java.security.MessageDigest
-
-import akka.NotUsed
-import akka.stream.{ Attributes, Outlet, Inlet, FlowShape }
-import akka.stream.scaladsl.{ Sink, Source }
-import akka.util.ByteString
-
-import scala.concurrent.Await
-import scala.concurrent.duration._
-
-class RecipeDigest extends RecipeSpec {
-
-  "Recipe for calculating digest" must {
-
-    "work" in {
-
-      val data = Source(List(
-        ByteString("abcdbcdecdef"),
-        ByteString("defgefghfghighijhijkijkljklmklmnlmnomnopnopq")))
-
-      //#calculating-digest
-      import akka.stream.stage._
-      class DigestCalculator(algorithm: String) extends GraphStage[FlowShape[ByteString, ByteString]] {
-        val in = Inlet[ByteString]("DigestCalculator.in")
-        val out = Outlet[ByteString]("DigestCalculator.out")
-        override val shape = FlowShape.of(in, out)
-
-        override def createLogic(inheritedAttributes: Attributes): GraphStageLogic = new GraphStageLogic(shape) {
-          val digest = MessageDigest.getInstance(algorithm)
-
-          setHandler(out, new OutHandler {
-            override def onPull(): Trigger = {
-              pull(in)
-            }
-          })
-
-          setHandler(in, new InHandler {
-            override def onPush(): Trigger = {
-              val chunk = grab(in)
-              digest.update(chunk.toArray)
-              pull(in)
-            }
-
-            override def onUpstreamFinish(): Unit = {
-              emit(out, ByteString(digest.digest()))
-              completeStage()
-            }
-          })
-
-        }
-      }
-      val digest: Source[ByteString, NotUsed] = data.via(new DigestCalculator("SHA-256"))
-      //#calculating-digest
-
-      Await.result(digest.runWith(Sink.head), 3.seconds) should be(
-        ByteString(
-          0x24, 0x8d, 0x6a, 0x61,
-          0xd2, 0x06, 0x38, 0xb8,
-          0xe5, 0xc0, 0x26, 0x93,
-          0x0c, 0x3e, 0x60, 0x39,
-          0xa3, 0x3c, 0xe4, 0x59,
-          0x64, 0xff, 0x21, 0x67,
-          0xf6, 0xec, 0xed, 0xd4,
-          0x19, 0xdb, 0x06, 0xc1))
-
-    }
-
-  }
-
-}