Collection<Integer> c = MinimalCollection.of(4, 16, 10, -1, 5);
    ImmutableList<Integer> list = ImmutableList.sortedCopyOf(c);
    assertEquals(asList(-1, 4, 5, 10, 16), list);
  }

  public void testSortedCopyOf_natural_empty() {
    Collection<Integer> c = MinimalCollection.of();
    ImmutableList<Integer> list = ImmutableList.sortedCopyOf(c);
    assertEquals(asList(), list);
  }