assertThrows(
        IllegalArgumentException.class,
        () -> numberOrdering.leastOf(Iterators.forArray(3, 4, 5, -1), -1));
  }

  public void testLeastOfIterable_singleton_0() {
    List<Integer> result = numberOrdering.leastOf(asList(3), 0);
    assertTrue(result instanceof RandomAccess);
    assertListImmutable(result);
    assertEquals(ImmutableList.<Integer>of(), result);
  }

    assertThrows(
        IllegalArgumentException.class,
        () -> numberOrdering.leastOf(Iterators.forArray(3, 4, 5, -1), -1));
  }

  public void testLeastOfIterable_singleton_0() {
    List<Integer> result = numberOrdering.leastOf(asList(3), 0);
    assertTrue(result instanceof RandomAccess);
    assertListImmutable(result);
    assertEquals(ImmutableList.<Integer>of(), result);
  }