public <T> boolean parse(Handler<T> handler, T target, CharSequence input) {
    if (input == null) throw new NullPointerException("input == null");
    return parse(handler, target, input, 0, input.length());
  }
@Test void parse_valuesAreRequired() {
    for (String missingValue : Arrays.asList("k1", "k1  ", "k1=v1,k2", "k1   ,k2=v1")) {
      assertThatThrownBy(() -> entrySplitter.parse(parseIntoMap, map, missingValue))
        .isInstanceOf(IllegalArgumentException.class)
        .hasMessage("Invalid input: missing key value separator '='");
    }
    assertThat(map.isEmpty());
  }