HDFS-8521. Add VisibleForTesting annotation to BlockPoolSlice#selectReplicaToDelete. (cmccabe)

(cherry picked from commit 806e407ac8896c4e669dba1fcf86fa5d6fee7c6d)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -525,6 +525,9 @@ Release 2.7.1 - UNRELEASED
     HDFS-8213. DFSClient should use hdfs.client.htrace HTrace configuration
     prefix rather than hadoop.htrace (cmccabe)
 
+    HDFS-8521. Add VisibleForTesting annotation to
+    BlockPoolSlice#selectReplicaToDelete. (cmccabe)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/BlockPoolSlice.java

@@ -57,7 +57,9 @@ import org.apache.hadoop.util.DiskChecker.DiskErrorException;
 import org.apache.hadoop.util.ShutdownHookManager;
 import org.apache.hadoop.util.Time;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.io.Files;
+
 /**
  * A block pool slice represents a portion of a block pool stored on a volume.  
  * Taken together, all BlockPoolSlices sharing a block pool ID across a 
@@ -568,6 +570,7 @@ class BlockPoolSlice {
     return replicaToKeep;
   }
 
+  @VisibleForTesting
   static ReplicaInfo selectReplicaToDelete(final ReplicaInfo replica1,
       final ReplicaInfo replica2) {
     ReplicaInfo replicaToKeep;