@Test
public void testAction8Error() {

    Action8<Integer, Integer, Integer, Integer, Integer, Integer, Integer, Integer> action = new Action8<Integer, Integer, Integer, Integer, Integer, Integer, Integer, Integer>() {
        @Override
        public void call(Integer t1, Integer t2, Integer t3, Integer t4, Integer t5, Integer t6, Integer t7, Integer t8) {
            throw new RuntimeException("Forced failure");
        }
    };
    Async.toAsync(action, Schedulers.immediate())
            .call(1, 2, 4, 8, 16, 32, 64, 128)
            .subscribe(new TestObserver<Object>(observer));
    verify(observer, times(1)).onError(any(Throwable.class));
    verify(observer, never()).onNext(null);
    verify(observer, never()).onCompleted();
}