HDFS-8834. TestReplication is not valid after HDFS-6482. (Contributed by Lei Xu)

(cherry picked from commit f4f1b8b267)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestReplication.java

@@ -18,6 +18,8 @@
 package org.apache.hadoop.hdfs;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -25,6 +27,10 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.io.RandomAccessFile;
 import java.net.InetSocketAddress;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.Random;
@@ -514,12 +520,28 @@ public class TestReplication {
         if (data_dir.listFiles().length == 0) {
           nonParticipatedNodeDirs.add(data_dir);
         } else {
+          assertNull("participatedNodeDirs has already been set.",
+              participatedNodeDirs);
           participatedNodeDirs = data_dir;
         }
       }
+      assertEquals(2, nonParticipatedNodeDirs.size());
 
       String blockFile = null;
-      File[] listFiles = participatedNodeDirs.listFiles();
+      final List<File> listFiles = new ArrayList<>();
+      Files.walkFileTree(participatedNodeDirs.toPath(),
+          new SimpleFileVisitor<java.nio.file.Path>() {
+            @Override
+            public FileVisitResult visitFile(
+                java.nio.file.Path file, BasicFileAttributes attrs)
+                throws IOException {
+              listFiles.add(file.toFile());
+              return FileVisitResult.CONTINUE;
+            }
+          }
+      );
+      assertFalse(listFiles.isEmpty());
+      int numReplicaCreated = 0;
       for (File file : listFiles) {
         if (file.getName().startsWith(Block.BLOCK_FILE_PREFIX)
             && !file.getName().endsWith("meta")) {
@@ -528,10 +550,12 @@ public class TestReplication {
             file1.mkdirs();
             new File(file1, blockFile).createNewFile();
             new File(file1, blockFile + "_1000.meta").createNewFile();
+            numReplicaCreated++;
           }
           break;
         }
       }
+      assertEquals(2, numReplicaCreated);
 
       fs.setReplication(new Path("/test"), (short) 3);
       cluster.restartDataNodes(); // Lets detect all DNs about dummy copied