diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 2c7fbc74fd2..1801d2fbe6e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -281,6 +281,9 @@ Trunk (Unreleased)
     HDFS-7634. Disallow truncation of Lazy persist files. (Yi Liu via
     Arpit Agarwal)
 
+    HDFS-7643. Test case to ensure lazy persist files cannot be truncated.
+    (Yi Liu via Arpit Agarwal)
+
 Release 2.7.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestLazyPersistFiles.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestLazyPersistFiles.java
index ad2197a631b..84ac2a59bc6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestLazyPersistFiles.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestLazyPersistFiles.java
@@ -23,13 +23,10 @@ import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
-import org.apache.hadoop.hdfs.server.datanode.DatanodeUtil;
-import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
 import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.Assert;
 import org.junit.Test;
 
-import java.io.File;
 import java.io.IOException;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
@@ -37,9 +34,6 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
 
 import static org.apache.hadoop.hdfs.DFSConfigKeys.*;
 import static org.apache.hadoop.hdfs.StorageType.DEFAULT;
@@ -247,6 +241,26 @@ public class TestLazyPersistFiles extends LazyPersistTestCase {
     }
   }
 
+  /**
+   * Truncate to lazy persist file is denied.
+   * @throws IOException
+   */
+  @Test
+  public void testTruncateIsDenied() throws IOException {
+    startUpCluster(true, -1);
+    final String METHOD_NAME = GenericTestUtils.getMethodName();
+    Path path = new Path("/" + METHOD_NAME + ".dat");
+
+    makeTestFile(path, BLOCK_SIZE, true);
+
+    try {
+      client.truncate(path.toString(), BLOCK_SIZE/2);
+      fail("Truncate to LazyPersist file did not fail as expected");
+    } catch (Throwable t) {
+      LOG.info("Got expected exception ", t);
+    }
+  }
+
   /**
    * If one or more replicas of a lazyPersist file are lost, then the file
    * must be discarded by the NN, instead of being kept around as a