### Question:
RLP { public static byte[] encodeLength(int length, int offset) { if (length < SIZE_THRESHOLD) { byte firstByte = (byte) (length + offset); return new byte[]{firstByte}; } else if (length < MAX_ITEM_LENGTH) { byte[] binaryLength; if (length > 0xFF) { binaryLength = intToBytesNoLeadZeroes(length); } else { binaryLength = new byte[]{(byte) length}; } byte firstByte = (byte) (binaryLength.length + offset + SIZE_THRESHOLD - 1); return concatenate(new byte[]{firstByte}, binaryLength); } else { throw new RuntimeException("Input too long"); } }  static int decodeInt(byte[] data, int index); static BigInteger decodeBigInteger(byte[] data, int index); static byte[] decodeIP4Bytes(byte[] data, int index); static int getFirstListElement(byte[] payload, int pos); static int getNextElementIndex(byte[] payload, int pos); static void fullTraverse(byte[] msgData, int level, int startPos,
                                    int endPos, int levelToIndex, Queue<Integer> index); static byte getCommandCode(byte[] data); @Nonnull static ArrayList<RLPElement> decode2(@CheckForNull byte[] msgData); static RLPList decodeList(byte[] msgData); @Nullable static RLPElement decode2OneItem(@CheckForNull byte[] msgData, int startPos); @Nonnull static UscAddress parseUscAddress(@Nullable byte[] bytes); @Nonnull static Coin parseCoin(@Nullable byte[] bytes); @Nullable static Coin parseCoinNonNullZero(byte[] bytes); @Nullable static Coin parseSignedCoinNonNullZero(byte[] bytes); static Coin parseCoinNullZero(@Nullable byte[] bytes); @Nullable static BlockDifficulty parseBlockDifficulty(@Nullable byte[] bytes); static byte[] encode(Object input); static byte[] encodeLength(int length, int offset); static byte[] encodeByte(byte singleByte); static byte[] encodeShort(short singleShort); static byte[] encodeInt(int singleInt); static byte[] encodeString(String srcString); static byte[] encodeBigInteger(BigInteger srcBigInteger); static byte[] encodeUscAddress(UscAddress addr); static byte[] encodeCoin(@Nullable Coin coin); static byte[] encodeCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeSignedCoinNonNullZero(@CheckForNull Coin coin); static byte[] encodeCoinNullZero(Coin coin); static byte[] encodeBlockDifficulty(BlockDifficulty difficulty); static byte[] encodeElement(@Nullable byte[] srcData); static byte[] encodeListHeader(int size); static byte[] encodeLongElementHeader(int length); static byte[] encodeSet(Set<ByteArrayWrapper> data); static byte[] encodeList(byte[]... elements);  }### Answer:
@Test public void testEncodeLength() { int length = 1; int offset = 128; byte[] encodedLength = encodeLength(length, offset); String expected = "81"; assertEquals(expected, Hex.toHexString(encodedLength)); length = 56; offset = 192; encodedLength = encodeLength(length, offset); expected = "f838"; assertEquals(expected, Hex.toHexString(encodedLength)); }
@Test @Ignore public void unsupportedLength() { int length = 56; int offset = 192; byte[] encodedLength; double maxLength = Math.pow(256, 8); try { encodedLength = encodeLength((int) maxLength, offset); System.out.println("length: " + length + ", offset: " + offset + ", encoded: " + Arrays.toString(encodedLength)); fail("Expecting RuntimeException: 'Input too long'"); } catch (RuntimeException e) { } }