@Test public void wrapFuture_futureIsUnexpectedError_idempotence() throws Exception {

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