@Test
 public void shouldConvertToVector() {
   final Value<Integer> value = of(1, 2, 3);
   final Vector<Integer> vector = value.toVector();
   if (value.isSingleValued()) {
     assertThat(vector).isEqualTo(Vector.of(1));
   } else {
     assertThat(vector).isEqualTo(Vector.of(1, 2, 3));
   }
 }