@Test public void shouldRecognizeMemoizedFunctions() { final Function4<Integer, Integer, Integer, Integer, Integer> f = (i1, i2, i3, i4) -> null; final Function4<Integer, Integer, Integer, Integer, Integer> memo = f.memoized(); assertThat(f.isMemoized()).isFalse(); assertThat(memo.isMemoized()).isTrue(); }