[SPARK-1817] Cosmetic updates

Author: kanzhang

core/src/main/scala/org/apache/spark/rdd/RDD.scala

@@ -655,7 +655,7 @@ abstract class RDD[T: ClassTag](
    * a map on the other).
    */
   def zip[U: ClassTag](other: RDD[U]): RDD[(T, U)] = {
-    zipPartitions(other, true) {(thisIter, otherIter) =>
+    zipPartitions(other, true) { (thisIter, otherIter) =>
       new Iterator[(T, U)] {
         def hasNext = (thisIter.hasNext, otherIter.hasNext) match {
           case (true, true) => true

core/src/test/scala/org/apache/spark/CheckpointSuite.scala

@@ -167,13 +167,13 @@ class CheckpointSuite extends FunSuite with LocalSparkContext with Logging {
     })
   }
 
-  test("ZippedRDD") {
+  test("ZippedPartitionsRDD") {
     testRDD(rdd => rdd.zip(rdd.map(x => x)))
     testRDDPartitions(rdd => rdd.zip(rdd.map(x => x)))
 
-    // Test that the ZippedPartition updates parent partitions
-    // after the parent RDD has been checkpointed and parent partitions have been changed.
-    // Note that this test is very specific to the current implementation of ZippedRDD.
+    // Test that ZippedPartitionsRDD updates parent partitions after parent RDDs have
+    // been checkpointed and parent partitions have been changed.
+    // Note that this test is very specific to the implementation of ZippedPartitionsRDD.
     val rdd = generateFatRDD()
     val zippedRDD = rdd.zip(rdd.map(x => x)).asInstanceOf[ZippedPartitionsRDD2[_, _, _]]
     zippedRDD.rdd1.checkpoint()
@@ -188,7 +188,7 @@ class CheckpointSuite extends FunSuite with LocalSparkContext with Logging {
         partitionBeforeCheckpoint.partitions(0).getClass &&
       partitionAfterCheckpoint.partitions(1).getClass !=
         partitionBeforeCheckpoint.partitions(1).getClass,
-      "Zipped RDD partition(0) or partition(1) not updated after parent RDDs are checkpointed"
+      "ZippedPartitionsRDD partition 0 (or 1) not updated after parent RDDs are checkpointed"
     )
   }