Iterable<Integer> mergedIterator = mergeSorted(iterables, Ordering.natural());

    assertEquals(Lists.newLinkedList(expected), Lists.newLinkedList(mergedIterator));
  }

  public void testMergeSorted_stable_allEqual() {
    ImmutableList<Integer> first = ImmutableList.of(0, 2, 4, 6, 8);
    ImmutableList<Integer> second = ImmutableList.of(1, 3, 5, 7, 9);

    Comparator<Object> comparator = Ordering.allEqual();

            new TestDatum("A", 2),
            new TestDatum("B", 1),
            new TestDatum("C", 1),
            new TestDatum("C", 2))
        .inOrder();
  }

  public void testMergeSorted_stable_allEqual() {
    ImmutableList<TestDatum> first = ImmutableList.of(new TestDatum("A", 1), new TestDatum("A", 2));
    ImmutableList<TestDatum> second =
        ImmutableList.of(new TestDatum("A", 3), new TestDatum("A", 4));