EchoRequest:
  EchoRequest:
    message:
      header:
        version: 4
        type: OFPT_ECHO_REQUEST
        length: 8
        xid: 0
    expectation: true
    description: plain EchoRequest message
  EchoRequestData:
    message:
      header:
        version: 4
        type: OFPT_ECHO_REQUEST
        length: 15
        xid: 0
      data: '01020304'
    expectation: true
    description: EchoRequest with data