adding updateStateByKey object lifecycle test

streaming/src/test/scala/spark/streaming/BasicOperationsSuite.scala

@@ -160,6 +160,51 @@ class BasicOperationsSuite extends TestSuiteBase {
     testOperation(inputData, updateStateOperation, outputData, true)
   }
 
+  test("updateStateByKey - object lifecycle") {
+    val inputData =
+      Seq(
+        Seq("a","b"),
+        null,
+        Seq("a","c","a"),
+        Seq("c"),
+        null,
+        null
+      )
+
+    val outputData =
+      Seq(
+        Seq(("a", 1), ("b", 1)),
+        Seq(("a", 1), ("b", 1)),
+        Seq(("a", 3), ("c", 1)),
+        Seq(("a", 3), ("c", 2)),
+        Seq(("c", 2)),
+        Seq()
+      )
+
+    val updateStateOperation = (s: DStream[String]) => {
+      class StateObject(var counter: Int = 0, var expireCounter: Int = 0) extends Serializable
+
+      // updateFunc clears a state when a StateObject is seen without new values twice in a row
+      val updateFunc = (values: Seq[Int], state: Option[StateObject]) => {
+        val stateObj = state.getOrElse(new StateObject)
+        values.foldLeft(0)(_ + _) match {
+          case 0 => stateObj.expireCounter += 1 // no new values
+          case n => { // has new values, increment and reset expireCounter
+            stateObj.counter += n
+            stateObj.expireCounter = 0
+          }
+        }
+        stateObj.expireCounter match {
+          case 2 => None // seen twice with no new values, give it the boot
+          case _ => Option(stateObj)
+        }
+      }
+      s.map(_ -> 1).updateStateByKey[StateObject](updateFunc).mapValues(_.counter)
+    }
+
+    testOperation(inputData, updateStateOperation, outputData, true)
+  }
+
   test("forgetting of RDDs - map and window operations") {
     assert(batchDuration === Seconds(1), "Batch duration has changed from 1 second")
 

streaming/src/test/scala/spark/streaming/TestSuiteBase.scala

@@ -28,6 +28,11 @@ class TestInputStream[T: ClassManifest](ssc_ : StreamingContext, input: Seq[Seq[
     logInfo("Computing RDD for time " + validTime)
     val index = ((validTime - zeroTime) / slideDuration - 1).toInt
     val selectedInput = if (index < input.size) input(index) else Seq[T]()
+
+    // lets us test cases where RDDs are not created
+    if (selectedInput == null)
+      return None
+
     val rdd = ssc.sc.makeRDD(selectedInput, numPartitions)
     logInfo("Created RDD " + rdd.id + " with " + selectedInput)
     Some(rdd)