@Test public void mapT1() { Tuple4<String, Integer, Integer, Integer> base = Tuples.of("Foo", 200, 300, 400); Tuple2<?,?> mapped = base.mapT1(String::length); assertThat(mapped).isNotSameAs(base) .hasSize(4) .containsExactly(3, base.getT2(), base.getT3(), base.getT4()); }