@Test
  public void emptyExtraDataThrowsException() {
    final Bytes bufferToInject = Bytes.EMPTY;

    assertThatThrownBy(() -> bftExtraDataEncoder.decodeRaw(bufferToInject))
        .isInstanceOf(IllegalArgumentException.class)
        .hasMessage("Invalid Bytes supplied - Bft Extra Data required.");
  }
This test specifically verifies that {@link IbftExtraDataCodec#decode(BlockHeader)} uses {@link
RLPInput#readInt()} rather than {@link RLPInput#readIntScalar()} to decode the round number
consensus/ibft/src/test/java/org/hyperledger/besu/consensus/ibft/IbftExtraDataRLPEncoderTest.java