@Test
 public void multipleMonoToFlux() {
   Mono<User> skylerMono = repository1.findFirst();
   Mono<User> marieMono = repository2.findFirst();
   Flux<User> flux = createFluxFromMultipleMono(skylerMono, marieMono);
   TestSubscriber.subscribe(flux).await().assertValues(User.SKYLER, MARIE).assertComplete();
 }
 @Test
 public void completableFutureConversion() {
   Mono<User> mono = repository.findFirst();
   CompletableFuture<User> future = fromMonoToCompletableFuture(mono);
   TestSubscriber<User> testSubscriber = new TestSubscriber<>();
   testSubscriber
       .bindTo(fromCompletableFutureToMono(future))
       .await()
       .assertValues(User.SKYLER)
       .assertComplete();
 }
 @Test
 public void singleConversion() {
   Mono<User> mono = repository.findFirst();
   Single<User> single = fromMonoToSingle(mono);
   TestSubscriber<User> testSubscriber = new TestSubscriber<>();
   testSubscriber
       .bindTo(fromSingleToMono(single))
       .await()
       .assertValues(User.SKYLER)
       .assertComplete();
 }