Index: src/test/org/apache/lucene/index/TestIndexWriterReader.java
===================================================================
--- src/test/org/apache/lucene/index/TestIndexWriterReader.java	(revision 945391)
+++ src/test/org/apache/lucene/index/TestIndexWriterReader.java	(working copy)
@@ -840,4 +840,23 @@
     w.close();
   }
 
+  public void testSharedReaders() throws Exception {
+    Directory dir = new MockRAMDirectory();
+    IndexWriter w = new IndexWriter(dir, new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer()));
+    IndexReader r = w.getReader();
+    Document doc = new Document();
+    doc.add(new Field("id", "1", Field.Store.NO, Field.Index.ANALYZED));
+    w.addDocument(doc);
+    IndexReader r2 = r.reopen();
+    w.addDocument(doc);
+    IndexReader r3 = r2.reopen();
+
+    assertEquals(r2.getSequentialSubReaders()[0].getFieldCacheKey(), r3.getSequentialSubReaders()[0].getFieldCacheKey());  
+    assertEquals(r2.getSequentialSubReaders()[0], r3.getSequentialSubReaders()[0]);
+    r.close();
+    r2.close();
+    r3.close();
+    w.close();
+  }
+
 }