Lists { static <T> Gen<List<T>> listsOf( Gen<T> generator, Gen<Integer> sizes) { return listsOf(generator, arrayList(), sizes).mix( listsOf(generator, linkedList(), sizes)); }  static Collector<T, List<T>, List<T>> arrayList(); static Collector<T, List<T>, List<T>> linkedList(); static Collector<T, A, A> toList(
      Supplier<A> collectionFactory);  }
@Test public void shouldGenerateBothTypesOfList() { Gen<List<Integer>> testee = listsOf( Generate.range(1, 1), Generate.constant(5)); assertThatGenerator(testee).generatesAllOf(Arrays.asList(1, 1, 1, 1, 1), new LinkedList<>(Arrays.asList(1, 1, 1, 1, 1))); }