// test empty list.
	buckets, err := obj.ListBuckets(context.Background(), BucketOptions{})
	if err != nil {
		t.Fatalf("%s: <ERROR> %s", instanceType, err)
	}
	if len(buckets) != 0 {
		t.Errorf("%s: Expected number of bucket to be `%d`, but instead found `%d`", instanceType, 0, len(buckets))
	}

	// add one and test exists.

    }

    /**
     * Calculates the time at which to next invoke the task.
     *
     * <p>This is guaranteed to be called immediately after the task has completed an iteration and
     * on the same thread as the previous execution of {@link
     * AbstractScheduledService#runOneIteration}.
     *
     * @return a schedule that defines the delay before the next execution.
     */
    // TODO(cpovirk): @ForOverride

    return Iterators.pollNext(descendingIterator());
  }

  @ParametricNullness
  protected E standardFirst() {
    return iterator().next();
  }

  @ParametricNullness
  protected E standardLast() {
    return descendingIterator().next();
  }

  @Override
  public NavigableSet<E> descendingSet() {
    return delegate().descendingSet();
  }

  /**

    }

    /**
     * Calculates the time at which to next invoke the task.
     *
     * <p>This is guaranteed to be called immediately after the task has completed an iteration and
     * on the same thread as the previous execution of {@link
     * AbstractScheduledService#runOneIteration}.
     *
     * @return a schedule that defines the delay before the next execution.
     */
    // TODO(cpovirk): @ForOverride

          LongMath.biggestBinomials[k] == Integer.MAX_VALUE
              || !fitsInLong(BigIntegerMath.binomial(LongMath.biggestBinomials[k] + 1, k)));
      // In the first case, any long is valid; in the second, we want to test that the next-bigger
      // long overflows.
    }
    int k = LongMath.biggestBinomials.length;
    assertFalse(fitsInLong(BigIntegerMath.binomial(2 * k, k)));

   * part of the smeared hash of the key not covered by the hashtable mask, whereas the low bits are
   * the "next" pointer (pointing to the next entry in the bucket chain), which will always be less
   * than or equal to the hashtable mask.
   *
   * <pre>
   * hash  = aaaaaaaa
   * mask  = 00000fff
   * next  = 00000bbb
   * entry = aaaaabbb
   * </pre>
   *

    return Iterators.pollNext(descendingIterator());
  }

  @ParametricNullness
  protected E standardFirst() {
    return iterator().next();
  }

  @ParametricNullness
  protected E standardLast() {
    return descendingIterator().next();
  }

  @Override
  public NavigableSet<E> descendingSet() {
    return delegate().descendingSet();
  }

  /**

    set("c", "c1", "c2")
    val iterator = cache.snapshots()
    assertThat(iterator.hasNext()).isTrue()
    iterator.next().use {
      assertThat(it.key()).isEqualTo("a")
      it.assertValue(0, "a1")
      it.assertValue(1, "a2")
    }
    assertThat(iterator.hasNext()).isTrue()
    iterator.next().use {
      assertThat(it.key()).isEqualTo("b")
      it.assertValue(0, "b1")
      it.assertValue(1, "b2")
    }

		},
	}

	// write a zip file
	buf := new(bytes.Buffer)
	w := NewWriter(buf)

	for _, test := range headerTests {
		h := &FileHeader{
			Name:  test.name,
			Extra: test.extra,
		}
		_, err := w.CreateHeader(h)
		if err != test.wanterr {
			t.Errorf("error=%v, want %v", err, test.wanterr)
		}
	}

	if err := w.Close(); err != nil {
		t.Fatal(err)
	}
}

    assertEquals(ImmutableList.of(789L, 123L), ImmutableList.copyOf(convertedValues));

    Iterator<Long> iterator = convertedValues.iterator();
    iterator.next();
    iterator.remove();
    assertEquals(ImmutableList.of("123"), mutableList);
  }

  public void testReverse() {
    Converter<Long, String> reverseConverter = STR_TO_LONG.reverse();