@Test public void mustBeAbleToUseOnCompleteSuccess() { final JavaTestKit probe = new JavaTestKit(system); final Iterable<String> input = Arrays.asList("A", "B", "C"); Source.from(input) .runWith( Sink.<String>onComplete( new Procedure<Try<Done>>() { @Override public void apply(Try<Done> param) throws Exception { probe.getRef().tell(param.get(), ActorRef.noSender()); } }), materializer); probe.expectMsgClass(Done.class); }