@Override
                  protected Set<String> create(String[] elements) {
                    return union(emptySet(), emptySet());
                  }
                })
            .named("empty U empty")
            .withFeatures(CollectionSize.ZERO, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(

     * If the virtual host is blank or null, returns an empty string.
     *
     * @param entity the RelatedQuery entity to extract the host key from
     * @return the virtual host key, or empty string if blank or null
     */
    protected String getHostKey(final RelatedQuery entity) {
        final String key = entity.getVirtualHost();
        return StringUtil.isBlank(key) ? StringUtil.EMPTY : key;
    }

    /**

func (b *Buffer) String() string {
	if b == nil {
		// Special case, useful in debugging.
		return "<nil>"
	}
	return string(b.buf[b.off:])
}

// 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()).

    }

    default void setDefaultLabelValue(final String value) {
        setSystemProperty(Constants.DEFAULT_LABEL_VALUE_PROPERTY, value);
        propMap.remove(DEFAULT_LABEL_VALUES);
    }

    default String getDefaultLabelValue() {
        return getSystemProperty(Constants.DEFAULT_LABEL_VALUE_PROPERTY, StringUtil.EMPTY);
    }

  }

  public void testEmptiesFirst() {
    Optional<String> empty = Optional.empty();
    Optional<String> abc = Optional.of("abc");
    Optional<String> z = Optional.of("z");

    Comparator<Optional<String>> comparator = emptiesFirst(comparing(String::length));
    testComparator(comparator, empty, z, abc);

    // Just demonstrate that no explicit type parameter is required

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

  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))

      assertThat(expected.message).isEqualTo("Code 1005 is reserved and may not be used.")
    }
  }

  @Test fun serverEmptyPing() {
    serverWriter.writePing(EMPTY)
    assertData("8900")
  }

  @Test fun clientEmptyPing() {
    clientWriter.writePing(EMPTY)
    assertData("898060b420bb")
  }

  @Test fun serverPingWithPayload() {
    serverWriter.writePing("Hello".encodeUtf8())
    assertData("890548656c6c6f")

	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 {

/**
 * @param {?string} str
 * @return {boolean} Whether the given string is null or is the empty string.
 * @public
 */
Platform.stringIsNullOrEmpty = function(str) {
  return !str;
};


/**
 * @param {?string} str
 * @return {string} Original str, if it is non-null. Otherwise empty string.
 */
Platform.nullToEmpty = function(str) {
  return str || "";
};


/**
 * @param {?string} str