{
  "topic": "BACnet tag header",
  "origin": "本文原创合成数据，未采集真实设备",
  "cases": [
    {
      "case_id": "短应用值",
      "kind": "正例",
      "input": {
        "hex": "21 2A"
      },
      "expected": {
        "tag": 2,
        "context": false,
        "kind": "value",
        "length": 1,
        "payload_hex": "2a"
      }
    },
    {
      "case_id": "扩展五字节",
      "kind": "正例",
      "input": {
        "hex": "65 05 01 02 03 04 05"
      },
      "expected": {
        "tag": 6,
        "context": false,
        "kind": "value",
        "length": 5,
        "payload_hex": "0102030405"
      }
    },
    {
      "case_id": "扩展标签号",
      "kind": "正例",
      "input": {
        "hex": "F9 14 01"
      },
      "expected": {
        "tag": 20,
        "context": true,
        "kind": "value",
        "length": 1,
        "payload_hex": "01"
      }
    },
    {
      "case_id": "开始标签",
      "kind": "正例",
      "input": {
        "hex": "3E"
      },
      "expected": {
        "tag": 3,
        "context": true,
        "kind": "opening",
        "length": 0,
        "payload_hex": ""
      }
    },
    {
      "case_id": "结束标签",
      "kind": "正例",
      "input": {
        "hex": "3F"
      },
      "expected": {
        "tag": 3,
        "context": true,
        "kind": "closing",
        "length": 0,
        "payload_hex": ""
      }
    },
    {
      "case_id": "缺负载",
      "kind": "显式负例",
      "input": {
        "hex": "65 05 01"
      },
      "expected_error": "负载长度不匹配"
    }
  ]
}