From df08e0de41aa9cd85c50c0f293ae6d72b997582a Mon Sep 17 00:00:00 2001
From: Stephen O'Donnell <stephen.odonnell@gmail.com>
Date: Mon, 19 Aug 2024 11:35:11 +0100
Subject: [PATCH] HDFS-17605. Reduce memory overhead of TestBPOfferService
 (#6996)

---
 .../hadoop/hdfs/server/datanode/TestBPOfferService.java      | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestBPOfferService.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestBPOfferService.java
index d5dbdbcd..2c848ae4 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestBPOfferService.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestBPOfferService.java
@@ -133,8 +133,9 @@ public class TestBPOfferService {
     mockNN2 = setupNNMock(1);
 
     // Set up a mock DN with the bare-bones configuration
-    // objects, etc.
-    mockDn = Mockito.mock(DataNode.class);
+    // objects, etc. Set as stubOnly to save memory and avoid Mockito holding
+    // references to each invocation. This can cause OOM in some runs.
+    mockDn = Mockito.mock(DataNode.class, Mockito.withSettings().stubOnly());
     Mockito.doReturn(true).when(mockDn).shouldRun();
     Configuration conf = new Configuration();
     File dnDataDir = new File(new File(TEST_BUILD_DATA, "dfs"), "data");
-- 
2.27.0