### Question:
CompletableProcessor extends Completable implements Processor { @Override public void onError(Throwable t) { terminate(TerminalNotification.error(t)); }  @Override void onSubscribe(Cancellable cancellable); @Override void onComplete(); @Override void onError(Throwable t); @Override void subscribe(final Subscriber subscriber);  }### Answer:
@Test public void testErrorBeforeListen() { CompletableProcessor processor = new CompletableProcessor(); processor.onError(DELIBERATE_EXCEPTION); rule.listen(processor).verifyFailure(DELIBERATE_EXCEPTION); }
@Test public void testErrorAfterListen() { CompletableProcessor processor = new CompletableProcessor(); rule.listen(processor).verifyNoEmissions(); processor.onError(DELIBERATE_EXCEPTION); rule.verifyFailure(DELIBERATE_EXCEPTION); }