@Test
public void mustBeAbleToUseBuffer() throws Exception {
final JavaTestKit probe = new JavaTestKit(system);
final List<String> input = Arrays.asList("A", "B", "C");
final CompletionStage<List<String>> future =
Source.from(input)
.buffer(2, OverflowStrategy.backpressure())
.grouped(4)
.runWith(Sink.<List<String>>head(), materializer);
List<String> result = future.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals(input, result);
}
