Fix scala style and other minor changes

streaming/src/test/scala/org/apache/spark/streaming/ReceiverInputDStreamSuite.scala

@@ -36,10 +36,10 @@ class ReceiverInputDStreamSuite extends TestSuiteBase with BeforeAndAfterAll {
     StreamingContext.getActive().map { _.stop() }
   }
 
-
   testWithoutWAL("createBlockRDD creates empty BlockRDD when no block info") { receiverStream =>
     val rdd = receiverStream.createBlockRDD(Time(0), Seq.empty)
     assert(rdd.isInstanceOf[BlockRDD[_]])
+    assert(!rdd.isInstanceOf[WriteAheadLogBackedBlockRDD[_]])
     assert(rdd.isEmpty())
   }
 
@@ -52,6 +52,7 @@ class ReceiverInputDStreamSuite extends TestSuiteBase with BeforeAndAfterAll {
 
     val rdd = receiverStream.createBlockRDD(Time(0), blockInfos)
     assert(rdd.isInstanceOf[BlockRDD[_]])
+    assert(!rdd.isInstanceOf[WriteAheadLogBackedBlockRDD[_]])
     val blockRDD = rdd.asInstanceOf[BlockRDD[_]]
     assert(blockRDD.blockIds.toSeq === blockIds)
   }
@@ -111,7 +112,7 @@ class ReceiverInputDStreamSuite extends TestSuiteBase with BeforeAndAfterAll {
     }
   }
 
-  private def testWithWAL(msg: String)(body: ReceiverInputDStream[_] => Unit):Unit = {
+  private def testWithWAL(msg: String)(body: ReceiverInputDStream[_] => Unit): Unit = {
     test(s"With WAL enabled: $msg") {
       runTest(enableWAL = true, body)
     }
@@ -131,6 +132,12 @@ class ReceiverInputDStreamSuite extends TestSuiteBase with BeforeAndAfterAll {
     }
   }
 
+  /**
+   * Create a block info for input to the ReceiverInputDStream.createBlockRDD
+   * @param withWALInfo Create block with WAL info in it
+   * @param createBlock Actually create the block in the BlockManager
+   * @return
+   */
   private def createBlockInfo(
       withWALInfo: Boolean,
       createBlock: Boolean = true): ReceivedBlockInfo = {