2.x: Clarify TestObserver.assertValueSet in docs and via tests

[akarnokd]

Clarify that {TestObserver|TestSubscriber}.assertValueSet checks for all received items to be in the provided set, but that set can contain additional elements that could have been received. Unit tests have been added to demonstrate the expected behavior.

Resolves: #6151.

[artem-zinnatullin]

I guess ideally method name would indicate that by using a word like contains, maybe add it to 3.x list of changes?

[sircelsius]

assertValuesIn(Collection<? extends T> expected)?

[akarnokd]

Posted #6153.

[Stephan202]

One grammar nit and one question :)

Thanks for the rapid response!

[Stephan202]

collection as well irrespective of the order they were received.

->

collection as well, irrespective of the order in which they were received.

[Stephan202]

As-is this method "ignores" duplicates, while assertValueCount doesn't. If a user wishes to assert that all values were received while allowing for duplicates, they could to .distinct().test(). Is this the preferred approach, and if so, is it worth documenting that too? (Maybe have an example of that in the test below?)

[akarnokd]

The aim is to provide some typical set of assertions with TestObserver. You can always modulate the input flow or simply enumerate contents of the TestObserver manually. I usually try to minimize the cases where additional operators are mentioned in the javadocs because it triggers "what about when using X" type of comments.

[codecov]

Codecov Report

Merging #6152 into 2.x will decrease coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##                2.x   #6152      +/-   ##
===========================================
- Coverage     98.26%   98.2%   -0.07%     
+ Complexity     6199    6197       -2     
===========================================
  Files           667     667              
  Lines         44857   44857              
  Branches       6213    6213              
===========================================
- Hits          44078   44051      -27     
- Misses          246     263      +17     
- Partials        533     543      +10

Impacted Files	Coverage Δ	Complexity Δ
.../java/io/reactivex/observers/BaseTestConsumer.java	100% <ø> (ø)	116 <0> (ø)	⬇️
.../operators/flowable/FlowableBlockingSubscribe.java	93.02% <0%> (-4.66%)	10% <0%> (-1%)
...ernal/operators/flowable/FlowableFlatMapMaybe.java	88.88% <0%> (-4.35%)	2% <0%> (ø)
...nternal/operators/parallel/ParallelReduceFull.java	91.08% <0%> (-3.97%)	2% <0%> (ø)
...ternal/operators/observable/ObservablePublish.java	96.46% <0%> (-3.54%)	11% <0%> (ø)
.../io/reactivex/disposables/CompositeDisposable.java	98.14% <0%> (-1.86%)	39% <0%> (-1%)
...internal/operators/flowable/FlowableSwitchMap.java	95.28% <0%> (-1.42%)	3% <0%> (ø)
...a/io/reactivex/internal/util/QueueDrainHelper.java	98.61% <0%> (-1.39%)	57% <0%> (-1%)
...l/operators/observable/ObservableFlatMapMaybe.java	88.23% <0%> (-1.31%)	2% <0%> (ø)
...ernal/operators/flowable/FlowableFromIterable.java	95.18% <0%> (-1.07%)	5% <0%> (ø)
... and 18 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 0e7b8ea...2dd535b. Read the comment docs.