diff --git a/lucene/test-framework/src/java/org/apache/lucene/index/BaseDocValuesFormatTestCase.java b/lucene/test-framework/src/java/org/apache/lucene/index/BaseDocValuesFormatTestCase.java
index 17caf084cba..5af847d8477 100644
--- a/lucene/test-framework/src/java/org/apache/lucene/index/BaseDocValuesFormatTestCase.java
+++ b/lucene/test-framework/src/java/org/apache/lucene/index/BaseDocValuesFormatTestCase.java
@@ -255,7 +255,7 @@ public abstract class BaseDocValuesFormatTestCase extends BaseIndexFileFormatTes
     HashMap<Integer,BytesRef> writtenValues = new HashMap<>(numDocs);
     
     // Small vocabulary ranges will be highly compressible 
-    int vocabRange = random().nextInt(Byte.MAX_VALUE);
+    int vocabRange = 1 + random().nextInt(Byte.MAX_VALUE - 1);
 
     for (int i = 0; i < numDocs; i++) {
       Document doc = new Document();