diff --git a/lucene/core/src/test/org/apache/lucene/search/TestMultiPhraseEnum.java b/lucene/core/src/test/org/apache/lucene/search/TestMultiPhraseEnum.java
index d31d6524836..f930e221137 100644
--- a/lucene/core/src/test/org/apache/lucene/search/TestMultiPhraseEnum.java
+++ b/lucene/core/src/test/org/apache/lucene/search/TestMultiPhraseEnum.java
@@ -86,6 +86,7 @@ public class TestMultiPhraseEnum extends LuceneTestCase {
     doc.add(new TextField("field", "bar", Field.Store.NO));
     writer.addDocument(doc);
     
+    writer.forceMerge(1);
     DirectoryReader ir = DirectoryReader.open(writer, true);
     writer.close();