@BeforeClass
public static void setUpRxSchedulers() {
    Scheduler immediate = new Scheduler() {
        @Override
        public Disposable scheduleDirect(@NonNull Runnable run, long delay, @NonNull TimeUnit unit) {
            // this prevents StackOverflowErrors when scheduling with a delay
            return super.scheduleDirect(run, 0, unit);
        }

        @Override
        public Scheduler.Worker createWorker() {
            return new ExecutorScheduler.ExecutorWorker(Runnable::run, false);
        }
    };

    RxJavaPlugins.setInitIoSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitComputationSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitNewThreadSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitSingleSchedulerHandler(scheduler -> immediate);
    RxAndroidPlugins.setInitMainThreadSchedulerHandler(scheduler -> immediate);
}
 

@BeforeClass
public static void init() {
    Scheduler immediate = new Scheduler() {
        @Override
        public Disposable scheduleDirect(@NonNull Runnable run, long delay, @NonNull TimeUnit unit) {
            return super.scheduleDirect(run, 0, unit);
        }

        @Override
        public Worker createWorker() {
            return new ExecutorScheduler.ExecutorWorker(Runnable::run, false);
        }
    };

    RxJavaPlugins.setInitIoSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitComputationSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitNewThreadSchedulerHandler(scheduler -> immediate);
    RxJavaPlugins.setInitSingleSchedulerHandler(scheduler -> immediate);
    RxAndroidPlugins.setInitMainThreadSchedulerHandler(scheduler -> immediate);

    OkHttpClient httpClient = TLSCompactHelper.getOKHttpClient();
    GsonConverterFactory gsonConverterFactory = GsonConverterFactory.create();
    RxJava2CallAdapterFactory rxJava2CallAdapterFactory = RxJava2CallAdapterFactory.create();
    CompositeDisposable disposable = new CompositeDisposable();

    photoService = new PhotoService(
            httpClient,
            gsonConverterFactory,
            rxJava2CallAdapterFactory,
            disposable
    );
}