Index: lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java	(revision 1064285)
+++ lucene/src/test/org/apache/lucene/index/TestIndexWriterReader.java	(working copy)
@@ -31,7 +31,6 @@
 import org.apache.lucene.document.Field.Index;
 import org.apache.lucene.document.Field.Store;
 import org.apache.lucene.document.Field.TermVector;
-import org.apache.lucene.index.codecs.CodecProvider;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.Query;
@@ -994,16 +993,14 @@
   }
   
   public void testNoTermsIndex() throws Exception {
-    // Some Codecs don't honor the ReaderTermsIndexDiviso, so skip the test if
+    // Some Codecs don't honor the ReaderTermsIndexDivisor, so skip the test if
     // they're picked.
     HashSet<String> illegalCodecs = new HashSet<String>();
     illegalCodecs.add("PreFlex");
-    illegalCodecs.add("MockRandom");
     illegalCodecs.add("SimpleText");
 
     IndexWriterConfig conf = newIndexWriterConfig(TEST_VERSION_CURRENT,
         new MockAnalyzer()).setReaderTermsIndexDivisor(-1);
-    
     // Don't proceed if picked Codec is in the list of illegal ones.
     if (illegalCodecs.contains(conf.getCodecProvider().getFieldCodec("f"))) return;
 
Index: lucene/src/test/org/apache/lucene/index/codecs/mockrandom/MockRandomCodec.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/codecs/mockrandom/MockRandomCodec.java	(revision 1064283)
+++ lucene/src/test/org/apache/lucene/index/codecs/mockrandom/MockRandomCodec.java	(working copy)
@@ -236,7 +236,11 @@
 
     try {
       if (random.nextBoolean()) {
-        state.termsIndexDivisor = _TestUtil.nextInt(random, 1, 10);
+        // if termsIndexDivisor is set to -1, we should not touch it. It means a
+        // test explicitly instructed not to load the terms index.
+        if (state.termsIndexDivisor != -1) {
+          state.termsIndexDivisor = _TestUtil.nextInt(random, 1, 10);
+        }
         if (LuceneTestCase.VERBOSE) {
           System.out.println("MockRandomCodec: fixed-gap terms index (divisor=" + state.termsIndexDivisor + ")");
         }