Index: src/test/org/apache/lucene/util/LuceneTestCase.java
===================================================================
--- src/test/org/apache/lucene/util/LuceneTestCase.java	(revision 1035418)
+++ src/test/org/apache/lucene/util/LuceneTestCase.java	(working copy)
@@ -35,6 +35,8 @@
 import org.apache.lucene.index.codecs.preflex.PreFlexCodec;
 import org.apache.lucene.index.codecs.preflexrw.PreFlexRWCodec;
 import org.apache.lucene.index.codecs.pulsing.PulsingCodec;
+import org.apache.lucene.index.codecs.simpletext.SimpleTextCodec;
+import org.apache.lucene.index.codecs.standard.StandardCodec;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.FieldCache;
 import org.apache.lucene.search.FieldCache.CacheEntry;
@@ -69,6 +71,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -152,6 +155,9 @@
   static final int TEST_ITER = Integer.parseInt(System.getProperty("tests.iter", "1"));
   /** Get the random seed for tests */
   static final String TEST_SEED = System.getProperty("tests.seed", "random");
+  /** Gets if a random codec per field should be used */
+  static final boolean TEST_RAMDOM_PER_FIELD_CODEC = Boolean.parseBoolean(System.getProperty("tests.randomcodec", "false"));
+
   
   private static final Pattern codecWithParam = Pattern.compile("(.*)\\(\\s*(\\d+)\\s*\\)");
 
@@ -316,6 +322,7 @@
     timeZone = TEST_TIMEZONE.equals("random") ? randomTimeZone(random) : TimeZone.getTimeZone(TEST_TIMEZONE);
     TimeZone.setDefault(timeZone);
     testsFailed = false;
+    randomCodecProvider = new RandomCodecProvider(random);
   }
   
   @AfterClass
@@ -636,7 +643,9 @@
       logmp.setCalibrateSizeByDeletes(r.nextBoolean());
       logmp.setMergeFactor(_TestUtil.nextInt(r, 2, 20));
     }
-    
+    if (TEST_RAMDOM_PER_FIELD_CODEC) {
+      c.setCodecProvider(randomCodecProvider);
+    }
     c.setReaderPooling(r.nextBoolean());
     c.setReaderTermsIndexDivisor(_TestUtil.nextInt(r, 1, 4));
     return c;
@@ -838,6 +847,8 @@
   // seed for individual test methods, changed in @before
   private long seed;
   
+  protected static CodecProvider randomCodecProvider;
+  
   private static final Random seedRand = new Random();
   protected static final Random random = new Random();
 
@@ -901,4 +912,40 @@
       }
     }
   }
+  
+  static class RandomCodecProvider extends CodecProvider {
+
+    private final Codec[] codecs;
+    private final Map<String, String> perFieldMap = new HashMap<String, String>();
+    private final Random random;
+
+    RandomCodecProvider(Random random) {
+      this.codecs = new Codec[] { new StandardCodec(), new SimpleTextCodec(),
+          new MockSepCodec(), new PulsingCodec(1 + random.nextInt(10)),
+          new MockVariableIntBlockCodec(1 + random.nextInt(10)),
+          new MockFixedIntBlockCodec(1 + random.nextInt(10)) };
+      for (int i = 0; i < codecs.length; i++) {
+        super.register(codecs[i]);
+      }
+      // register preflex to support reading of old indexes
+      this.register(new PreFlexCodec());
+      this.random = random;
+    }
+
+    @Override
+    public synchronized String getFieldCodec(String name) {
+      if (!perFieldMap.containsKey(name)) { // select a codec at random
+        setFieldCodec(name, codecs[random.nextInt(codecs.length)].name);
+      }
+      return super.getFieldCodec(name);
+    }
+
+    @Override
+    public synchronized void setFieldCodec(String field, String codec) {
+      if (!perFieldMap.containsKey(field)) {
+        perFieldMap.put(field, codec);
+      }
+      super.setFieldCodec(field, codec);
+    }
+  }
 }