Index: lucene/src/test-framework/org/apache/lucene/util/LuceneTestCase.java
===================================================================
--- lucene/src/test-framework/org/apache/lucene/util/LuceneTestCase.java	(revision 1131057)
+++ lucene/src/test-framework/org/apache/lucene/util/LuceneTestCase.java	(working copy)
@@ -60,6 +60,7 @@
 import org.apache.lucene.store.FSDirectory;
 import org.apache.lucene.store.LockFactory;
 import org.apache.lucene.store.MockDirectoryWrapper;
+import org.apache.lucene.store.MockDirectoryWrapper.Throttling;
 import org.apache.lucene.util.FieldCacheSanityChecker.Insanity;
 import org.junit.*;
 import org.junit.rules.TestWatchman;
@@ -160,6 +161,8 @@
   public static final String TEST_LINE_DOCS_FILE = System.getProperty("tests.linedocsfile", "europarl.lines.txt.gz");
   /** whether or not to clean threads between test invocations: "false", "perMethod", "perClass" */
   public static final String TEST_CLEAN_THREADS = System.getProperty("tests.cleanthreads", "perClass");
+  /** whether or not to clean threads between test invocations: "false", "perMethod", "perClass" */
+  public static final Throttling TEST_THROTTLING = TEST_NIGHTLY ? Throttling.SOMETIMES : Throttling.NEVER;
 
   private static final Pattern codecWithParam = Pattern.compile("(.*)\\(\\s*(\\d+)\\s*\\)");
 
@@ -938,8 +941,9 @@
     Directory impl = newDirectoryImpl(r, TEST_DIRECTORY);
     MockDirectoryWrapper dir = new MockDirectoryWrapper(r, impl);
     stores.put(dir, Thread.currentThread().getStackTrace());
+    dir.setThrottling(TEST_THROTTLING);
     return dir;
-  }
+   }
 
   /**
    * Returns a new Directory instance, with contents copied from the
@@ -985,6 +989,7 @@
         dir.setLockFactory(lf);
       }
       stores.put(dir, Thread.currentThread().getStackTrace());
+      dir.setThrottling(TEST_THROTTLING);
       return dir;
     } catch (Exception e) {
       throw new RuntimeException(e);
@@ -1003,6 +1008,7 @@
     }
     MockDirectoryWrapper dir = new MockDirectoryWrapper(r, impl);
     stores.put(dir, Thread.currentThread().getStackTrace());
+    dir.setThrottling(TEST_THROTTLING);
     return dir;
   }