{
  "expression": ["properties"],
  "inputs": [[{}, {"properties": {"x": 5}}]],
  "expected": {
    "compiled": {
      "result": "success",
      "isFeatureConstant": false,
      "isZoomConstant": true,
      "type": "object"
    },
    "outputs": [{"x": 5}],
    "serialized": ["properties"]
  }
}