@Test
public void success_GeneratePrivateKey_from_hexString() {

    String hexStr = "ab4195d4123f0594e5341c45134c5938cc5913d34aa951234c5938cc2a6eb487";
    byte[] result = HexEncoder.getBytes(hexStr);
    assertThat(result.length, is(32));
    PrivateKey privateKey = PrivateKeyEd25519.fromHexString(hexStr);
    byte[] raw = privateKey.getRaw();
    assertThat(raw, is(result));
}