/** no block information. */
 @Test
 public void no_info() {
   BlockBuilder builder = new BlockBuilder();
   builder.seek(1000);
   List<DirectInputFragment> results = builder.compute(50, 100, true, true);
   assertThat(results.size(), is(10));
 }
 /** block information is sparse. */
 @Test
 public void sparse() {
   BlockBuilder builder = new BlockBuilder();
   builder.seek(5);
   builder.add(10, "a");
   builder.seek(5);
   builder.add(10, "a");
   builder.seek(5);
   builder.add(10, "a");
   builder.seek(5);
   builder.add(10, "a");
   builder.seek(5);
   builder.add(10, "a");
   builder.seek(5);
   List<DirectInputFragment> results = builder.compute(50, 100, true, true);
   assertThat(results.size(), is(1));
   assertThat(find(results, 0).getOwnerNodeNames(), hasItem("a"));
 }