diff --git a/lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java b/lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java
index 7897a70fd0b..8a551cd8689 100644
--- a/lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java
+++ b/lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java
@@ -349,6 +349,9 @@ public class TestIndexWriterReader extends LuceneTestCase {
 
     void close(boolean doWait) throws Throwable {
       didClose = true;
+      if (doWait) {
+        mainWriter.waitForMerges();
+      }
       mainWriter.close(doWait);
     }
 
diff --git a/lucene/src/test/org/apache/lucene/util/_TestUtil.java b/lucene/src/test/org/apache/lucene/util/_TestUtil.java
index e91b50123c2..7ae6f4e0cfc 100644
--- a/lucene/src/test/org/apache/lucene/util/_TestUtil.java
+++ b/lucene/src/test/org/apache/lucene/util/_TestUtil.java
@@ -231,5 +231,11 @@ public class _TestUtil {
     // keep number of open files lowish
     LogMergePolicy lmp = (LogMergePolicy) w.getMergePolicy();
     lmp.setMergeFactor(Math.min(5, lmp.getMergeFactor()));
+
+    MergeScheduler ms = w.getConfig().getMergeScheduler();
+    if (ms instanceof ConcurrentMergeScheduler) {
+      ((ConcurrentMergeScheduler) ms).setMaxThreadCount(2);
+      ((ConcurrentMergeScheduler) ms).setMaxMergeCount(3);
+    }
   }
 }