}
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> showVersionAndExit() {
        if (commandLine.hasOption(CLIManager.SHOW_VERSION_AND_EXIT)) {
            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> showVersion() {

    expectContents();
  }

  // retainAll(null)

  /*
   * AbstractCollection fails the retainAll(null) test when the subject
   * collection is empty, but we'd still like to test retainAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)

        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> nonRecursive() {
        if (commandLine.hasOption(CLIManager.NON_RECURSIVE)) {
            return Optional.of(Boolean.TRUE);
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> updateSnapshots() {

    data.write("8a00".decodeHex()) // Pong
    data.write("80026c6f".decodeHex()) // lo
    clientReader.processNextFrame()
    callback.assertPong(EMPTY)
    callback.assertPong(EMPTY)
    callback.assertPong(EMPTY)
    callback.assertPong(EMPTY)
    callback.assertTextMessage("Hello")
  }

  @Test fun clientTwoFrameCompressedHelloWithPongs() {

// [Scanner] to read more data into the slice and try again with a
// longer slice starting at the same point in the input.
//
// The function is never called with an empty data slice unless atEOF
// is true. If atEOF is true, however, data may be non-empty and,
// as always, holds unprocessed text.
type SplitFunc func(data []byte, atEOF bool) (advance int, token []byte, err error)

// Errors returned by Scanner.
var (

func (b *Buffer) Peek(n int) ([]byte, error) {
	if b.Len() < n {
		return b.buf[b.off:], io.EOF
	}
	return b.buf[b.off : b.off+n], nil
}

// empty reports whether the unread portion of the buffer is empty.
func (b *Buffer) empty() bool { return len(b.buf) <= b.off }

// Len returns the number of bytes of the unread portion of the buffer;
// b.Len() == len(b.Bytes()).

	if spc {
		s.WriteString(KvDoubleQuote)
	}
	return s.String()
}

// KVS - is a shorthand for some wrapper functions
// to operate on list of key values.
type KVS []KV

// Empty - return if kv is empty
func (kvs KVS) Empty() bool {
	return len(kvs) == 0
}

// Clone - returns a copy of the KVS
func (kvs KVS) Clone() KVS {
	return append(make(KVS, 0, len(kvs)), kvs...)
}

	lc := lru.NewLRU(10, func(key string, value string) { evicted = append(evicted, key, value) }, 150*time.Millisecond)

	k, v, ok := lc.GetOldest()
	if k != "" {
		t.Fatalf("should be empty")
	}
	if v != "" {
		t.Fatalf("should be empty")
	}
	if ok {
		t.Fatalf("should be false")
	}

	lc.Add("key1", "val1")

	time.Sleep(100 * time.Millisecond) // not enough to expire
	if lc.Len() != 1 {

  public void testConcat() {
    assertThat(Shorts.concat()).isEqualTo(EMPTY);
    assertThat(Shorts.concat(EMPTY)).isEqualTo(EMPTY);
    assertThat(Shorts.concat(EMPTY, EMPTY, EMPTY)).isEqualTo(EMPTY);
    assertThat(Shorts.concat(ARRAY1)).isEqualTo(ARRAY1);
    assertThat(Shorts.concat(ARRAY1)).isNotSameInstanceAs(ARRAY1);
    assertThat(Shorts.concat(EMPTY, ARRAY1, EMPTY)).isEqualTo(ARRAY1);
    assertThat(Shorts.concat(ARRAY1, ARRAY1, ARRAY1))

}

// Empty buf through repeated reads into fub.
// The initial contents of buf corresponds to the string s.
func empty(t *testing.T, testname string, buf *Buffer, s string, fub []byte) {
	check(t, testname+" (empty 1)", buf, s)

	for {
		n, err := buf.Read(fub)
		if n == 0 {
			break
		}
		if err != nil {
			t.Errorf(testname+" (empty 2): err should always be nil, found err == %s", err)