{
  "fixture": "Modbus 0x17 读写结构",
  "cases": [
    {
      "case_id": "重叠先写后读",
      "kind": "正例",
      "result": {
        "read_address": 1,
        "write_address": 2,
        "read_values": [
          20,
          99
        ],
        "after": [
          10,
          20,
          99,
          100,
          101,
          60
        ]
      }
    },
    {
      "case_id": "写字节数不符",
      "kind": "显式负例",
      "rejected": "写区长度错误"
    }
  ],
  "assertions_passed": 2,
  "scope": "合成输入离线演算；未接真实设备"
}