diff --git a/akka-stream-testkit/src/main/scala/akka/stream/testkit/StreamTestKit.scala b/akka-stream-testkit/src/main/scala/akka/stream/testkit/StreamTestKit.scala
index 039f8c9bfc..b37d0a78b2 100644
--- a/akka-stream-testkit/src/main/scala/akka/stream/testkit/StreamTestKit.scala
+++ b/akka-stream-testkit/src/main/scala/akka/stream/testkit/StreamTestKit.scala
@@ -8,9 +8,9 @@ import akka.actor.ActorSystem
 import akka.actor.DeadLetterSuppression
 import akka.stream._
 import akka.stream.impl._
+import akka.testkit.TestProbe
 import akka.stream.impl.StreamLayout.Module
 import akka.stream.scaladsl._
-import akka.testkit.TestProbe
 import org.reactivestreams.{ Publisher, Subscriber, Subscription }
 import scala.collection.immutable
 import scala.concurrent.duration._
diff --git a/akka-stream-testkit/src/main/scala/akka/stream/testkit/scaladsl/TestSink.scala b/akka-stream-testkit/src/main/scala/akka/stream/testkit/scaladsl/TestSink.scala
index 0ae3a86e03..dc62a462f7 100644
--- a/akka-stream-testkit/src/main/scala/akka/stream/testkit/scaladsl/TestSink.scala
+++ b/akka-stream-testkit/src/main/scala/akka/stream/testkit/scaladsl/TestSink.scala
@@ -3,14 +3,12 @@
  */
 package akka.stream.testkit.scaladsl
 
-import akka.stream._
-import akka.stream.impl._
+import akka.actor.ActorSystem
 import akka.stream.OperationAttributes.none
+import akka.stream._
 import akka.stream.scaladsl._
 import akka.stream.testkit._
 
-import akka.actor.ActorSystem;
-
 /**
  * Factory methods for test sinks.
  */
diff --git a/akka-stream-testkit/src/test/scala/akka/stream/testkit/Utils.scala b/akka-stream-testkit/src/test/scala/akka/stream/testkit/Utils.scala
index 29f439fca9..ae3666a875 100644
--- a/akka-stream-testkit/src/test/scala/akka/stream/testkit/Utils.scala
+++ b/akka-stream-testkit/src/test/scala/akka/stream/testkit/Utils.scala
@@ -1,6 +1,7 @@
 package akka.stream.testkit
 
 import akka.actor.ActorRef
+import akka.actor.ActorRefWithCell
 import akka.stream.FlowMaterializer
 import akka.stream.impl._
 import akka.testkit.TestProbe
@@ -33,4 +34,11 @@ object Utils {
       case _ ⇒ block
     }
 
+  def assertDispatcher(ref: ActorRef, dispatcher: String): Unit = ref match {
+    case r: ActorRefWithCell ⇒
+      if (r.underlying.props.dispatcher != dispatcher)
+        throw new AssertionError(s"Expected $ref to use dispatcher [$dispatcher], yet used: [${r.underlying.props.dispatcher}]")
+    case _ ⇒
+      throw new Exception(s"Unable to determine dispatcher of $ref")
+  }
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSinkSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSinkSpec.scala
index 6263fc18f4..aebdaf8bd1 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSinkSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSinkSpec.scala
@@ -5,12 +5,19 @@ package akka.stream.io
 
 import java.io.File
 
-import akka.actor.{ ActorCell, ActorSystem, RepointableActorRef }
+import akka.actor.ActorSystem
+import akka.stream.impl.ActorFlowMaterializerImpl
+import akka.stream.impl.StreamSupervisor
+import akka.stream.impl.StreamSupervisor.Children
 import akka.stream.scaladsl.Source
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
-import akka.stream.{ ActorFlowMaterializer, ActorFlowMaterializerSettings, ActorOperationAttributes }
-import akka.util.{ ByteString, Timeout }
+import akka.stream.testkit.StreamTestKit
+import akka.stream.ActorFlowMaterializer
+import akka.stream.ActorFlowMaterializerSettings
+import akka.stream.ActorOperationAttributes
+import akka.util.ByteString
+import akka.util.Timeout
 
 import scala.collection.mutable.ListBuffer
 import scala.concurrent.Await
@@ -93,8 +100,9 @@ class SynchronousFileSinkSpec extends AkkaSpec(UnboundedMailboxConfig) {
         try {
           Source(() ⇒ Iterator.continually(TestByteStrings.head)).runWith(SynchronousFileSink(f))(mat)
 
-          val ref = Await.result(sys.actorSelection("/user/$a/flow-1-2*").resolveOne(), timeout.duration)
-          ref.asInstanceOf[RepointableActorRef].underlying.asInstanceOf[ActorCell].dispatcher.id should ===("akka.stream.default-file-io-dispatcher")
+          mat.asInstanceOf[ActorFlowMaterializerImpl].supervisor.tell(StreamSupervisor.GetChildren, testActor)
+          val ref = expectMsgType[Children].children.find(_.path.toString contains "File").get
+          assertDispatcher(ref, "akka.stream.default-file-io-dispatcher")
         } finally shutdown(sys)
       }
     }
@@ -111,8 +119,9 @@ class SynchronousFileSinkSpec extends AkkaSpec(UnboundedMailboxConfig) {
             .withAttributes(ActorOperationAttributes.dispatcher("akka.actor.default-dispatcher"))
             .run()(mat)
 
-          val ref = Await.result(sys.actorSelection("/user/$a/flow-1-2*").resolveOne(), timeout.duration)
-          ref.asInstanceOf[RepointableActorRef].underlying.asInstanceOf[ActorCell].dispatcher.id should ===("akka.actor.default-dispatcher")
+          mat.asInstanceOf[ActorFlowMaterializerImpl].supervisor.tell(StreamSupervisor.GetChildren, testActor)
+          val ref = expectMsgType[Children].children.find(_.path.toString contains "File").get
+          assertDispatcher(ref, "akka.actor.default-dispatcher")
         } finally shutdown(sys)
       }
     }
@@ -132,3 +141,4 @@ class SynchronousFileSinkSpec extends AkkaSpec(UnboundedMailboxConfig) {
   }
 
 }
+
diff --git a/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSourceSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSourceSpec.scala
index 19cefa99ed..bffbb5afbd 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSourceSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/io/SynchronousFileSourceSpec.scala
@@ -3,16 +3,25 @@
  */
 package akka.stream.io
 
-import java.io.{ File, FileWriter }
+import java.io.File
+import java.io.FileWriter
 import java.util.Random
 
-import akka.actor.{ ActorCell, RepointableActorRef, ActorSystem }
+import akka.actor.ActorSystem
+import akka.stream.ActorFlowMaterializer
+import akka.stream.ActorFlowMaterializerSettings
+import akka.stream.ActorOperationAttributes
+import akka.stream.OperationAttributes
+import akka.stream.impl.ActorFlowMaterializerImpl
+import akka.stream.impl.StreamSupervisor
+import akka.stream.impl.StreamSupervisor.Children
 import akka.stream.io.SynchronousFileSourceSpec.Settings
 import akka.stream.scaladsl.Sink
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
-import akka.stream.{ ActorOperationAttributes, ActorFlowMaterializer, ActorFlowMaterializerSettings, OperationAttributes }
-import akka.util.{ Timeout, ByteString }
+import akka.stream.testkit.scaladsl.TestSink
+import akka.util.ByteString
+import akka.util.Timeout
 
 import scala.concurrent.Await
 import scala.concurrent.duration._
@@ -157,16 +166,17 @@ class SynchronousFileSourceSpec extends AkkaSpec(UnboundedMailboxConfig) {
         }
       }
 
-    "use dedicated file-io-dispatcher by default" in {
+    "use dedicated file-io-dispatcher by default" in assertAllStagesStopped {
       val sys = ActorSystem("dispatcher-testing", UnboundedMailboxConfig)
       val mat = ActorFlowMaterializer()(sys)
       implicit val timeout = Timeout(500.millis)
 
       try {
-        SynchronousFileSource(manyLines).runWith(Sink.ignore)(mat)
+        val p = SynchronousFileSource(manyLines).runWith(TestSink.probe())(mat)
 
-        val ref = Await.result(sys.actorSelection("/user/$a/flow-*").resolveOne(), timeout.duration)
-        ref.asInstanceOf[RepointableActorRef].underlying.asInstanceOf[ActorCell].dispatcher.id should ===("akka.stream.default-file-io-dispatcher")
+        mat.asInstanceOf[ActorFlowMaterializerImpl].supervisor.tell(StreamSupervisor.GetChildren, testActor)
+        val ref = expectMsgType[Children].children.find(_.path.toString contains "File").get
+        try assertDispatcher(ref, "akka.stream.default-file-io-dispatcher") finally p.cancel()
       } finally shutdown(sys)
     }
 
@@ -176,12 +186,13 @@ class SynchronousFileSourceSpec extends AkkaSpec(UnboundedMailboxConfig) {
       implicit val timeout = Timeout(500.millis)
 
       try {
-        SynchronousFileSource(manyLines)
+        val p = SynchronousFileSource(manyLines)
           .withAttributes(ActorOperationAttributes.dispatcher("akka.actor.default-dispatcher"))
-          .runWith(Sink.ignore)(mat)
+          .runWith(TestSink.probe())(mat)
 
-        val ref = Await.result(sys.actorSelection("/user/$a/flow-*").resolveOne(), timeout.duration)
-        ref.asInstanceOf[RepointableActorRef].underlying.asInstanceOf[ActorCell].dispatcher.id should ===("akka.actor.default-dispatcher")
+        mat.asInstanceOf[ActorFlowMaterializerImpl].supervisor.tell(StreamSupervisor.GetChildren, testActor)
+        val ref = expectMsgType[Children].children.find(_.path.toString contains "File").get
+        try assertDispatcher(ref, "akka.actor.default-dispatcher") finally p.cancel()
       } finally shutdown(sys)
     }
   }
diff --git a/akka-stream/src/main/scala/akka/stream/io/SynchronousFileSource.scala b/akka-stream/src/main/scala/akka/stream/io/SynchronousFileSource.scala
index fc6dd64ab9..a48131b155 100644
--- a/akka-stream/src/main/scala/akka/stream/io/SynchronousFileSource.scala
+++ b/akka-stream/src/main/scala/akka/stream/io/SynchronousFileSource.scala
@@ -29,6 +29,7 @@ object SynchronousFileSource {
    */
   def apply(f: File, chunkSize: Int = DefaultChunkSize): Source[ByteString, Future[Long]] =
     new Source(new SynchronousFileSource(f, chunkSize, DefaultAttributes, Source.shape("SynchronousFileSource")))
+      .named(DefaultAttributes.nameOption.get)
 
   /**
    * Creates a synchronous (Java 6 compatible) Source from a Files contents.