From d0c786db4de99a72802e844a3a2a717a64845cda Mon Sep 17 00:00:00 2001
From: Ahmed Hussein <50450311+amahussein@users.noreply.github.com>
Date: Tue, 27 Oct 2020 20:56:40 -0500
Subject: [PATCH] HDFS-15460.
 TestFileCreation#testServerDefaultsWithMinimalCaching fails intermittently.
 (#2406)

---
 .../apache/hadoop/hdfs/TestFileCreation.java  | 20 ++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java
index 93687b680a..a7cf68b101 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestFileCreation.java
@@ -239,9 +239,8 @@ public void testServerDefaultsWithCaching()
    * Test that server defaults are updated on the client after cache expiration.
    */
   @Test
-  public void testServerDefaultsWithMinimalCaching()
-      throws IOException, InterruptedException {
-    // Create cluster with an explicit block size param
+  public void testServerDefaultsWithMinimalCaching() throws Exception  {
+    // Create cluster with an explicit block size param.
     Configuration clusterConf = new HdfsConfiguration();
     long originalBlockSize = DFS_BLOCK_SIZE_DEFAULT * 2;
     clusterConf.setLong(DFS_BLOCK_SIZE_KEY, originalBlockSize);
@@ -273,10 +272,17 @@ public void testServerDefaultsWithMinimalCaching()
               defaults.getDefaultStoragePolicyId());
       doReturn(newDefaults).when(spyNamesystem).getServerDefaults();
 
-      Thread.sleep(1);
-      defaults = dfsClient.getServerDefaults();
-      // Value is updated correctly
-      assertEquals(updatedDefaultBlockSize, defaults.getBlockSize());
+      // Verify that the value is updated correctly. Wait for 3 seconds.
+      GenericTestUtils.waitFor(()->{
+        try {
+          FsServerDefaults currDef = dfsClient.getServerDefaults();
+          return (currDef.getBlockSize() == updatedDefaultBlockSize);
+        } catch (IOException e) {
+          // do nothing;
+          return false;
+        }
+      }, 1, 3000);
+
     } finally {
       cluster.shutdown();
     }