code: @Test public void testAddDeletion(){
    Deletion deletion=new Deletion(System.currentTimeMillis());
    SlicePredicate slicePredicate=new SlicePredicate();
    slicePredicate.addToColumn_names(StringSerializer.get().toByteBuffer("c_name"));
    deletion.setPredicate(slicePredicate);
    batchMutate.addDeletion("key1",columnFamilies,deletion);
    assertEquals(1,batchMutate.getMutationMap().get(StringSerializer.get().toByteBuffer("key1")).size());
    deletion=new Deletion(System.currentTimeMillis());
    slicePredicate=new SlicePredicate();
    slicePredicate.addToColumn_names(StringSerializer.get().toByteBuffer("c_name2"));
    deletion.setPredicate(slicePredicate);
    batchMutate.addDeletion("key1",columnFamilies,deletion);
    assertEquals(2,batchMutate.getMutationMap().get(StringSerializer.get().toByteBuffer("key1")).get("Standard1").size());
  }
  