@Test
 public void shouldConvertToStream() {
   final Value<Integer> value = of(1, 2, 3);
   final Stream<Integer> stream = value.toStream();
   if (value.isSingleValued()) {
     assertThat(stream).isEqualTo(Stream.of(1));
   } else {
     assertThat(stream).isEqualTo(Stream.of(1, 2, 3));
   }
 }