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

  public void testSortedCopyOf_natural_singleton() {
    Collection<Integer> c = MinimalCollection.of(100);
    ImmutableList<Integer> list = ImmutableList.sortedCopyOf(c);
    assertEquals(asList(100), list);
  }