Scala Unit testing for ProcessAllWindowFunction

Question

After Reading the official flink testing documentation ( https://ci.apache.org/projects/flink/flink-docs-release-1.9/dev/stream/testing.html ) I was able to develop tests for a ProcessFunction, using a Test Harness, something like this:

pendingPartitionBuilder = new PendingPartitionBuilder(":::some_name", "")

testHarness =
  new OneInputStreamOperatorTestHarness[StaticAdequacyTilePublishedData, PendingPartition](
    new ProcessOperator[StaticAdequacyTilePublishedData, PendingPartition](pendingPartitionBuilder)
  )

testHarness.open()

now, I'm trying to do the same for a ProcessAllWindowFunction, that looks like this:

class MapVersionValidationDistributor(batchSize: Int) extends
  ProcessAllWindowFunction[MapVersionValidation, Seq[StaticAdequacyTilePublishedData],TimeWindow] {

lazy val state: ValueState[Long] = getRuntimeContext .getState(new ValueStateDescriptor[Long]("latestMapVersion", classOf[Long]))
(...)

First I realized I can't use TestHarness for ProcessAllWindowFunction, because it doesn't have a processElement method. In this case, what unit test strategy should I follow?

EDIT: At the moment my test code looks like this:

val collector = mock[Collector[Seq[StaticAdequacyTilePublishedData]]]
    val mvv = new MapVersionValidationDistributor(1)
    val input3 = Iterable(new MapVersionValidation("123",Seq(TileValidation(1,true,Seq(1,3,4)))))

    val ctx = mock[mvv.Context]
    val streamContext =  mock[RuntimeContext]
    mvv.setRuntimeContext(streamContext)

    mvv.open(mock[Configuration])
    mvv.process(ctx,input3,collector)

and I'm getting this error:

 Unexpected call: <mock-3> RuntimeContext.getState[T](ValueStateDescriptor{name=latestMapVersion, defaultValue=null, serializer=null}) Expected: inAnyOrder { }

Answer 1

You don't really need test harness to unit test the process method of the ProcessAllWindowFunction . The process function takes 3 arguments: Context , Iterable[IN] , Collector[OUT] . You can use some library depending on the language used to mock the Context . You can also easily implement or mock the Collector depending on your prerefences here. And the Iterable[IN] is just an Iterable containing the elements of Your window, that would be passed to the function after the window is triggered.