### Question:
DefaultEventCorrelator implements EventCorrelator { @Override public String register(CompletableFuture<Void> future) { var correlationId = randomUUID().toString(); futures.put(correlationId, future); log.debug("registered: {}", correlationId); return correlationId; } DefaultEventCorrelator(); @Override String register(CompletableFuture<Void> future); @Override void received(String correlationId); @Override void failed(String correlationId, Exception e);  }### Answer:
@Test public void register() { var correlationId = underTest.register(future); assertThat(futures.get(correlationId), is(future)); }