Index: lucene/facet/src/test/org/apache/lucene/facet/taxonomy/directory/TestDirectoryTaxonomyWriter.java
===================================================================
--- lucene/facet/src/test/org/apache/lucene/facet/taxonomy/directory/TestDirectoryTaxonomyWriter.java	(revision 1490938)
+++ lucene/facet/src/test/org/apache/lucene/facet/taxonomy/directory/TestDirectoryTaxonomyWriter.java	(working copy)
@@ -17,11 +17,12 @@
 import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
+import org.apache.lucene.index.IndexWriterConfig.OpenMode;
 import org.apache.lucene.index.IndexWriterConfig;
-import org.apache.lucene.index.IndexWriterConfig.OpenMode;
 import org.apache.lucene.index.SegmentInfos;
 import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.Directory;
+import org.apache.lucene.util._TestUtil;
 import org.junit.Test;
 
 /*
@@ -412,5 +413,34 @@
     taxoWriter.close();
     dir.close();
   }
-  
+
+  @Test
+  public void testHugeLabel() throws Exception {
+    Directory dir = newDirectory();
+    DirectoryTaxonomyWriter taxoWriter = new DirectoryTaxonomyWriter(dir);
+
+    // Add one huge label:
+    while (true) {
+      String s = _TestUtil.randomRealisticUnicodeString(random(), 32767, 32767);
+      if (s.indexOf('\u001f') != -1) {
+        continue;
+      }
+      taxoWriter.addCategory(new CategoryPath("dimdimdim", s));
+      break;
+    }
+
+    // Then lots of tiny ones:
+    for(int i=0;i<10000;i++) {
+      String s = _TestUtil.randomUnicodeString(random());
+      if (s.length() == 0) {
+        continue;
+      }
+      if (s.indexOf('\u001f') != -1) {
+        continue;
+      }
+      taxoWriter.addCategory(new CategoryPath("dim", s));
+    }
+    taxoWriter.close();
+    dir.close();
+  }
 }