@Test public void wrapFuture_futureIsUnexpectedUncheckedException_idempotence() throws Exception {

  RuntimeException exception = new RuntimeException("test");
  CompletionStage<?> stage =
      Maybe.catchException(IOException.class, exceptionally(exception));
  stage = Maybe.catchException(IOException.class, stage);
  stage = Maybe.catchException(MyException.class, stage);
  stage = Maybe.catchException(Error.class, stage);
  assertCauseOf(ExecutionException.class, stage).isSameAs(exception);
}