LocalListenerRegistry { Flux<MailboxListener.ReactiveMailboxListener> getLocalMailboxListeners(RegistrationKey registrationKey) { return Flux.fromIterable(listenersByKey.getOrDefault(registrationKey, ImmutableSet.of())); } LocalListenerRegistry();   }
@Test void getLocalMailboxListenersShouldReturnEmptyWhenNone() { assertThat(testee.getLocalMailboxListeners(KEY_1).collectList().block()) .isEmpty(); }