{
  "name": "invalid/duplicate-column-key",
  "rules": {
    "columns": [
      {
        "key": "v"
      },
      {
        "key": "v"
      }
    ]
  },
  "rows": [
    {
      "v": "x"
    }
  ],
  "expect": {
    "throws": "duplicate column key \"v\""
  }
}