Operator: SequenceEqual

[benjchristensen]

http://msdn.microsoft.com/en-us/library/hh229024(v=vs.103).aspx
http://msdn.microsoft.com/en-us/library/hh212108(v=vs.103).aspx

[benjchristensen]

Looking at these implementations it seems that by using zip it will emit a sequence of true/false values rather than a single boolean specifying if the entire sequence is true/false.

I think it is supposed to emit only a single value based on reading the MSDN docs.

@mairbek If you re-read the docs, is it supposed to be a single value, or sequence of values emitted? If single, can you submit a fix? Probably a reduce type function that keeps going until it finds a false otherwise if it hits onComplete/onError the same on both sides it returns true.

[mairbek]

@benjchristensen okay, I'll submit the patch.

[mairbek]

Reduce doesn't seems to be a good choice in this case since it would wait for all pairs of events, even if first two were different.

I will start by implementing All Operation #21 and applying it to a zip of two observables.

[benjchristensen]

Okay, thanks.

[mairbek]

This happens to be more complicated that I've expected.

I've come up with a test case that fails on all + zip implementation. Looks like zip operation completes the observation as fast as first observable completes which leads to wrong behaviour of sequenceEqual operation.

        @Test
        public void testSequenceEqual3() {
            Observable<Integer> first = Observable.toObservable(1, 2);
            Observable<Integer> second = Observable.toObservable(1, 2, 3);
            @SuppressWarnings("unchecked")
            Observer<Boolean> result = mock(Observer.class);
            sequenceEqual(first, second).subscribe(result);
            verify(result, times(1)).onNext(false);
            verify(result, times(1)).onCompleted();
            verifyNoMoreInteractions(result);
        }

[benjchristensen]

Done.