String doubled = "a,,b,c";
    Iterable<String> letters = COMMA_SPLITTER.split(doubled);
    assertThat(letters).containsExactly("a", "", "b", "c").inOrder();
  }

  public void testCharacterSplitWithDoubleDelimiterAndSpace() {
    String doubled = "a,, b,c";
    Iterable<String> letters = COMMA_SPLITTER.split(doubled);
    assertThat(letters).containsExactly("a", "", " b", "c").inOrder();
  }