2.x: coverage, add SingleToFlowableTest

[ggikko]

Add "SingleToFlowableTest" to cover toFlowable with test.

[codecov]

Codecov Report

Merging #5673 into 2.x will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##                2.x    #5673      +/-   ##
============================================
- Coverage     96.28%   96.26%   -0.03%     
  Complexity     5817     5817              
============================================
  Files           633      633              
  Lines         41552    41552              
  Branches       5751     5751              
============================================
- Hits          40007    39998       -9     
- Misses          613      621       +8     
- Partials        932      933       +1

Impacted Files	Coverage Δ	Complexity Δ
...tivex/internal/schedulers/InstantPeriodicTask.java	61.11% <0%> (-5.56%)	7% <0%> (-2%)
...nternal/operators/parallel/ParallelReduceFull.java	91.17% <0%> (-3.93%)	2% <0%> (ø)
...l/operators/observable/ObservableFlatMapMaybe.java	88.23% <0%> (-3.93%)	2% <0%> (ø)
.../operators/observable/ObservableFlatMapSingle.java	88.8% <0%> (-3.74%)	2% <0%> (ø)
.../internal/operators/flowable/FlowableInterval.java	94.44% <0%> (-2.78%)	3% <0%> (ø)
...ternal/operators/observable/ObservablePublish.java	92.98% <0%> (-2.64%)	11% <0%> (+1%)
...ex/internal/subscribers/InnerQueuedSubscriber.java	96.07% <0%> (-1.97%)	18% <0%> (-1%)
...a/io/reactivex/internal/queue/MpscLinkedQueue.java	98.03% <0%> (-1.97%)	17% <0%> (-1%)
...a/io/reactivex/internal/util/QueueDrainHelper.java	60.28% <0%> (-1.42%)	32% <0%> (-1%)
...vex/internal/operators/flowable/FlowableCache.java	92.61% <0%> (-1.35%)	7% <0%> (ø)
... and 23 more

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[akarnokd]

My mistake, looked at the complexity column.

[ggikko]

well.. I thought it was not covered "if (DisposableHelper.validate(this.d, d))" in SingleToFlowable

I got it. thanks for link.

[ggikko]

I have a question. There are many duplicate codes in Test code. How about zip these codes to one method for cleaning.

[akarnokd]

You mean TestHelper? The types are different and they can't be reasonably factored out.

[ggikko]

I see. :)