{
  "expression": ["concat", "a", "b", "c"],
  "inputs": [[{}, {}]],
  "expected": {
    "compiled": {
      "result": "success",
      "isFeatureConstant": true,
      "isZoomConstant": true,
      "type": "string"
    },
    "outputs": ["abc"],
    "serialized": "abc"
  }
}