@Test
public void testBigIntegerToBytesNegative() {

    byte[] expecteds = new byte[]{(byte) 0xff, 0x0, 0x13, (byte) 0x88};
    BigInteger b = BigInteger.valueOf(-16772216);
    byte[] actuals = ByteUtil.bigIntegerToBytes(b);
    assertArrayEquals(expecteds, actuals);
}