*
     * @return the application type string, or empty string if not set
     */
    public static String getAppType() {
        final String appType = System.getenv(FESS_APP_TYPE);
        if (StringUtil.isNotBlank(appType)) {
            return appType;
        }
        return StringUtil.EMPTY;
    }

    /**

        assertArrayEquals(emptyHash, avChannelBindings.getRaw(), "Value should be an empty array when empty hash is provided");
    }

    /**
     * Test that the constructor stores the reference to the input byte array.
     * Note: The implementation does not create a defensive copy.
     */
    @Test
    void testConstructorStoresReference() {

     *
     * @param in the input file (must not be {@literal null})
     * @param inputEncoding the input file encoding (must not be {@literal null} or empty)
     * @param out the output file (must not be {@literal null})
     * @param outputEncoding the output file encoding (must not be {@literal null} or empty)
     * @return the number of characters copied
     */

	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 {

     *
     * @return an {@link Optional} containing the boolean value {@code true} if specified, or empty
     */
    Optional<Boolean> force();

    /**
     * Should imply "yes" to all questions.
     *
     * @return an {@link Optional} containing the boolean value {@code true} if specified, or empty
     */
    Optional<Boolean> yes();

    /**
     * Returns the list of encryption goals to be executed.

     *
     * @return default upgrade options
     */
    public static UpgradeOptions createDefaultOptions() {
        UpgradeOptions options = mock(UpgradeOptions.class);
        when(options.all()).thenReturn(Optional.empty());
        when(options.infer()).thenReturn(Optional.empty());
        when(options.model()).thenReturn(Optional.empty());

        assertEquals("Malformed kerberos ticket", exception.getMessage(), "The exception message should indicate a malformed ticket.");
    }

    /**
     * Test constructor with an empty token.
     * Empty token causes readObject() to return null, which leads to NullPointerException.
     */
    @Test
    void testConstructor_EmptyToken() {
        // 1. GIVEN
        byte[] emptyToken = new byte[0];

ECL0001={0} not found
ECL0008=argument[{0}] is null.
ECL0009=argument[{0}] is illegal. because {1}.
ECL0010=argument[{0}] is null or empty string.
ECL0011=argument[{0}] is null or empty array.
ECL0012=argument[{0}] is null or empty collection.
ECL0013=argument[{0}] is null or empty map.
ECL0014=argument[{0}] which is null the index of array is negative integer.
ECL0015=argument[{0}] which is null the index of array exceed the size of array[{1}].

   * otherwise returns an empty stream.
   */
  public static <T> Stream<T> stream(com.google.common.base.Optional<T> optional) {
    return optional.isPresent() ? Stream.of(optional.get()) : Stream.empty();
  }

  /**
   * If a value is present in {@code optional}, returns a stream containing only that element,
   * otherwise returns an empty stream.
   *