@Test public void create_invalid() {

  assertThatThrownBy(() -> BaggageField.create(null))
    .isInstanceOf(NullPointerException.class);
  assertThatThrownBy(() -> BaggageField.create(""))
    .isInstanceOf(IllegalArgumentException.class);
  assertThatThrownBy(() -> BaggageField.create("    "))
    .isInstanceOf(IllegalArgumentException.class);
}