fix(buffer): cleanup notifier subscription when unsubscribed

[kwonoj]

Code snippet

var source = Rx.Observable.timer(0, 25).buffer(Rx.Observable.interval(50)).take(3);
var subscription = source.subscribe(
  function (x) {
    console.log('Next: %s', x);
  },
  function (err) {
    console.log('Error: %s', err);
  },
  function () {
    console.log('Completed');
  });

emits buffered elements like

Next: 0,1
Next: 2,3
Next: 4,5
Completed

--> But process does not exit here

This PR let buffer unsubscribes closingNotifier to avoid above issue.

[staltz]

Good catch. Should we also add a test for that?

[kwonoj]

Would be better to have, bit unsure how to design test case for this. @staltz any suggestions?

[benlesh]

Looks like we need to add tests for the work? Coveralls is complaining on this one, @kwonoj

[kwonoj]

Yes I agree, as asked above bit unsure how to design test case for this. May I borrow some tips from you for insight?

[staltz]

@kwonoj here's a draft:

  it('should', function () {
    var a = hot('--1--2--^--3--4--5---6----7--8--9---0---|');
    var unsub =         '              !                  ';
    var subs =          '^             !                  ';
    var b = hot('--------^--a-------b---cd|               ');
    var bsubs =         '^             !                  '; // <-----------------
    var expected =      '---a-------b---                  ';
    var expectedValues = {
      a: ['3'],
      b: ['4', '5']
    };
    expectObservable(a.buffer(b), unsub).toBe(expected, expectedValues);
    expectSubscriptions(a.subscriptions).toBe(subs);
    expectSubscriptions(b.subscriptions).toBe(bsubs); // <------------------
  });

[kwonoj]

@staltz Appreciate for help! I'll try to add those test cases.

[kwonoj]

Updated PR by copy-paste of @staltz 's help 😁

[staltz]

Looks good. I wonder why Coveralls is reporting less coverage (by -0.01%, negligible in my opinion).

[kwonoj]

why Coveralls is reporting less coverage

@staltz This was reason I started looking into #557, for this specific it seems because current coverage try to check *spec.js also.

[benlesh]

merged with 1b30aa9 ... thanks @kwonoj!