Test ColdSignal.filter
Test ColdSignal.map
Test ColdSignal.scan
Test ColdSignal.reduce
Test ColdSignal.combinePrevious
Test ColdSignal.skip
Test ColdSignal.skipRepeats
Test ColdSignal.skipWhile
Test ColdSignal.take
Test ColdSignal.takeLast
Test ColdSignal.takeWhile
Test ColdSignal.takeUntil