@Test
public void asyncActionSingle() throws Exception {

    AmazonWebServiceRequest someRequest = AmazonWebServiceRequest.NOOP;
    final MockAsyncClient<AmazonWebServiceRequest, String> client = new MockAsyncClient<>(someRequest, "some response");
    Single<String> single = AwsObservableExt.asyncActionSingle(supplier -> client.someAsyncOperation(supplier.handler()));
    TestScheduler testScheduler = Schedulers.test();
    final AssertableSubscriber<String> subscriber = single.subscribeOn(testScheduler).test();
    testScheduler.triggerActions();
    subscriber.assertNoValues();
    subscriber.assertNotCompleted();
    client.run();
    testScheduler.triggerActions();
    subscriber.assertValueCount(1);
    subscriber.assertValue("some response");
    subscriber.assertCompleted();
}