builder.append("C");
    assertEquals("C", iterator.next());
    assertFalse(iterator.hasNext());
  }

  public void testFixedLengthSimpleSplit() {
    String simple = "abcde";
    Iterable<String> letters = Splitter.fixedLength(2).split(simple);
    assertThat(letters).containsExactly("ab", "cd", "e").inOrder();
  }

  public void testFixedLengthSplitEqualChunkLength() {

    builder.append("C");
    assertEquals("C", iterator.next());
    assertFalse(iterator.hasNext());
  }

  public void testFixedLengthSimpleSplit() {
    String simple = "abcde";
    Iterable<String> letters = Splitter.fixedLength(2).split(simple);
    assertThat(letters).containsExactly("ab", "cd", "e").inOrder();
  }

  public void testFixedLengthSplitEqualChunkLength() {

    //     the smaller of these blocks with the far end of the other one. That leaves us with a
    //     smaller version of the same problem.
    //     Say we are rotating abcdefgh by 5. We start with abcde|fgh. The smaller block is [fgh]:
    //     [abc]de|[fgh] -> [fgh]de|[abc]. Now [fgh] is in the right place, but we need to swap [de]
    //     with [abc]: fgh[de]|a[bc] -> fgh[bc]|a[de]. Now we need to swap [a] with [bc]:

//		{Offset: 21, Length: 4},  // Hole fragment for 21..24
//	}
//
// Then the content of the resulting sparse file with a Header.Size of 25 is:
//
//	var sparseFile = "\x00"*2 + "abcde" + "\x00"*11 + "fgh" + "\x00"*4
type (
	sparseDatas []sparseEntry
	sparseHoles []sparseEntry
)

// validateSparseEntries reports whether sp is a valid sparse map.