{
  "expression": ["string", ["get", "x"]],
  "inputs": [
    [{}, {"properties": {"x": "1"}}],
    [{}, {"properties": {"x": 1}}],
    [{}, {"properties": {"x": false}}],
    [{}, {"properties": {"x": null}}]
  ],
  "expected": {
    "compiled": {
      "result": "success",
      "isFeatureConstant": false,
      "isZoomConstant": true,
      "type": "string"
    },
    "outputs": [
      "1",
      {
        "error": "Expected value to be of type string, but found number instead."
      },
      {
        "error": "Expected value to be of type string, but found boolean instead."
      },
      {"error": "Expected value to be of type string, but found null instead."}
    ],
    "serialized": ["string", ["get", "x"]]
  }
}