Update ReceiverTrackerSuite.scala

streaming/src/test/scala/org/apache/spark/streaming/scheduler/ReceiverTrackerSuite.scala

@@ -32,6 +32,7 @@ class ReceiverTrackerSuite extends TestSuiteBase {
   val executors: List[String] = List("0", "1", "2", "3")
 
   test("receiver scheduling - all or none have preferred location") {
+
     def parse(s: String): Array[Array[String]] = {
       val outerSplit = s.split("\\|")
       val loc = new Array[Array[String]](outerSplit.length)
@@ -41,18 +42,20 @@ class ReceiverTrackerSuite extends TestSuiteBase {
       }
       loc
     }
+
     def testScheduler(numReceivers: Int, preferredLocation: Boolean, allocation: String) {
       val receivers =
         if (preferredLocation) {
-          (0 until numReceivers).map(i => new DummyReceiver(host =
+          Array.tabulate(numReceivers)(i => new DummyReceiver(host =
             Some(((i + 1) % executors.length).toString)))
         } else {
-          (0 until numReceivers).map(i => new DummyReceiver)
+          Array.tabulate(numReceivers)(_ => new DummyReceiver)
         }
       val locations = launcher.scheduleReceivers(receivers, executors)
       val expectedLocations = parse(allocation)
       assert(locations.deep === expectedLocations.deep)
     }
+
     testScheduler(numReceivers = 5, preferredLocation = false, allocation = "0|1|2|3|0")
     testScheduler(numReceivers = 3, preferredLocation = false, allocation = "0,3|1|2")
     testScheduler(numReceivers = 4, preferredLocation = true, allocation = "1|2|3|0")