Different behaviors of SequenceEqual in Rx.Net and RxJava

[zsxwing]

Looks SequenceEqual in Rxjava is not correct.

In Rx.Net, SequenceEqual returns an Observable which only has one element indicating if these two sequences are same. For example,

            var o = Observable.SequenceEqual(Observable.Range(1, 100), Observable.Range(1, 100));
            var s = o.Subscribe(
                v => Console.WriteLine("Equal = " + v),
                e =>  Console.WriteLine(e),
                () => Console.WriteLine("onCompleted")
                );
            Console.WriteLine("Press any key...");
            Console.ReadKey();

Outputs:

Equal = True
onCompleted
Press any key...

But in RxJava, the following codes:

        Observable
                .sequenceEqual(Observable.range(1, 100),
                        Observable.range(1, 100)).toBlockingObservable()
                .forEach(new Action1<Boolean>() {
                    @Override
                    public void call(Boolean t1) {
                        System.out.println(t1);
                    }
                });

Output 100 trues.

[akarnokd]

I've noticed that using zip to pair up values is not the same behavior as in Rx.NET. In Rx.NET, the operator checks if the length of the streams are the same or not. Even if we don't want to do that, one could add a simple all operator after the zip:

public static <T> Observable<Boolean> sequenceEqual(Observable<? extends T> first, 
        Observable<? extends T> second, Func2<? super T, ? super T, Boolean> equality) {
    return zip(first, second, equality).all(Functions.<Boolean>identity());
}

Using the materialized view is not an option as errors need to be propagated directly and not compared (and generally, equals doesn't work on Throwables).

[zsxwing]

I can take this this weekend.

[zsxwing]

fixed in #575