{
  "expression": [
    "to-string",
    [
      "format",
      "a",
      {},
      "b",
      {
        "font-scale": 2
      },
      "c",
      {
        "text-font": [
          "literal",
          [
            "a",
            "b"
          ]
        ]
      }
    ]
  ],
  "inputs": [
    [
      {},
      {}
    ]
  ],
  "expected": {
    "compiled": {
      "result": "success",
      "isFeatureConstant": true,
      "isZoomConstant": true,
      "type": "string"
    },
    "outputs": [
      "abc"
    ],
    "serialized": "abc"
  }
}