Iterable<String> threeCommasThenThreeSpaces = Splitter.on(", ").split(fourCommasAndFourSpaces);
    assertThat(threeCommasThenThreeSpaces).containsExactly(",,,", "   ").inOrder();
  }

  public void testStringSplitWithEmptyString() {
    assertThrows(IllegalArgumentException.class, () -> Splitter.on(""));
  }

  public void testStringSplitOnEmptyString() {
    Iterable<String> notMuch = Splitter.on(".").split("");