public void testClear() {
   DocumentsWriterDeleteQueue queue = new DocumentsWriterDeleteQueue();
   assertFalse(queue.anyChanges());
   queue.clear();
   assertFalse(queue.anyChanges());
   final int size = 200 + random().nextInt(500) * RANDOM_MULTIPLIER;
   int termsSinceFreeze = 0;
   int queriesSinceFreeze = 0;
   for (int i = 0; i < size; i++) {
     Term term = new Term("id", "" + i);
     if (random().nextInt(10) == 0) {
       queue.addDelete(new TermQuery(term));
       queriesSinceFreeze++;
     } else {
       queue.addDelete(term);
       termsSinceFreeze++;
     }
     assertTrue(queue.anyChanges());
     if (random().nextInt(10) == 0) {
       queue.clear();
       queue.tryApplyGlobalSlice();
       assertFalse(queue.anyChanges());
     }
   }
 }