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

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