[
  {
    "id": "$firstN baseline",
    "operator": "$firstN",
    "kind": "baseline",
    "operand": "all",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": 2
      }
    },
    "input": {},
    "srotax": {
      "bson": "{\"v\": [{\"$numberInt\": \"3\"}, {\"$numberInt\": \"1\"}]}",
      "present": true
    }
  },
  {
    "id": "$firstN input: null",
    "operator": "$firstN",
    "kind": "null",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": null
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: missing",
    "operator": "$firstN",
    "kind": "missing",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: zero",
    "operator": "$firstN",
    "kind": "zero",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": 0
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: negative",
    "operator": "$firstN",
    "kind": "negative",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": -2
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: decimal",
    "operator": "$firstN",
    "kind": "decimal",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": 2.5
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: numeric string",
    "operator": "$firstN",
    "kind": "numeric string",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": "12"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: text",
    "operator": "$firstN",
    "kind": "text",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": "hello"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: empty string",
    "operator": "$firstN",
    "kind": "empty string",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": ""
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: boolean",
    "operator": "$firstN",
    "kind": "boolean",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": true
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: false",
    "operator": "$firstN",
    "kind": "false",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": false
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: typed date",
    "operator": "$firstN",
    "kind": "typed date",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": {
        "$date": "2026-01-15T15:00:00Z"
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: decimal128",
    "operator": "$firstN",
    "kind": "decimal128",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": {
        "$numberDecimal": "1.25"
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: empty array",
    "operator": "$firstN",
    "kind": "empty array",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": []
    },
    "srotax": {
      "bson": "{\"v\": []}",
      "present": true
    }
  },
  {
    "id": "$firstN input: numeric array",
    "operator": "$firstN",
    "kind": "numeric array",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": [
        1,
        2,
        3
      ]
    },
    "srotax": {
      "bson": "{\"v\": [{\"$numberInt\": \"1\"}, {\"$numberInt\": \"2\"}]}",
      "present": true
    }
  },
  {
    "id": "$firstN input: mixed array",
    "operator": "$firstN",
    "kind": "mixed array",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": [
        1,
        null,
        "x",
        3
      ]
    },
    "srotax": {
      "bson": "{\"v\": [{\"$numberInt\": \"1\"}, null]}",
      "present": true
    }
  },
  {
    "id": "$firstN input: nested array",
    "operator": "$firstN",
    "kind": "nested array",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": [
        [
          1,
          2
        ],
        [
          3
        ]
      ]
    },
    "srotax": {
      "bson": "{\"v\": [[{\"$numberInt\": \"1\"}, {\"$numberInt\": \"2\"}], [{\"$numberInt\": \"3\"}]]}",
      "present": true
    }
  },
  {
    "id": "$firstN input: empty object",
    "operator": "$firstN",
    "kind": "empty object",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": {}
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: object",
    "operator": "$firstN",
    "kind": "object",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": {
        "x": 1
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN input: ISO date string",
    "operator": "$firstN",
    "kind": "ISO date string",
    "operand": "input",
    "expression": {
      "$firstN": {
        "input": "$probe",
        "n": 2
      }
    },
    "input": {
      "probe": "2026-01-15T15:00:00Z"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN input must be an array"
    }
  },
  {
    "id": "$firstN n: null",
    "operator": "$firstN",
    "kind": "null",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": null
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: missing",
    "operator": "$firstN",
    "kind": "missing",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: zero",
    "operator": "$firstN",
    "kind": "zero",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": 0
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: negative",
    "operator": "$firstN",
    "kind": "negative",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": -2
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: decimal",
    "operator": "$firstN",
    "kind": "decimal",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": 2.5
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: numeric string",
    "operator": "$firstN",
    "kind": "numeric string",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": "12"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: text",
    "operator": "$firstN",
    "kind": "text",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": "hello"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: empty string",
    "operator": "$firstN",
    "kind": "empty string",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": ""
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: boolean",
    "operator": "$firstN",
    "kind": "boolean",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": true
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: false",
    "operator": "$firstN",
    "kind": "false",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": false
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: typed date",
    "operator": "$firstN",
    "kind": "typed date",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": {
        "$date": "2026-01-15T15:00:00Z"
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: decimal128",
    "operator": "$firstN",
    "kind": "decimal128",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": {
        "$numberDecimal": "1.25"
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: empty array",
    "operator": "$firstN",
    "kind": "empty array",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": []
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: numeric array",
    "operator": "$firstN",
    "kind": "numeric array",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": [
        1,
        2,
        3
      ]
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: mixed array",
    "operator": "$firstN",
    "kind": "mixed array",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": [
        1,
        null,
        "x",
        3
      ]
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: nested array",
    "operator": "$firstN",
    "kind": "nested array",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": [
        [
          1,
          2
        ],
        [
          3
        ]
      ]
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: empty object",
    "operator": "$firstN",
    "kind": "empty object",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": {}
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: object",
    "operator": "$firstN",
    "kind": "object",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": {
        "x": 1
      }
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN n: ISO date string",
    "operator": "$firstN",
    "kind": "ISO date string",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ],
        "n": "$probe"
      }
    },
    "input": {
      "probe": "2026-01-15T15:00:00Z"
    },
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN n must be a positive 64-bit integer"
    }
  },
  {
    "id": "$firstN omit input",
    "operator": "$firstN",
    "kind": "omitted named argument",
    "operand": "input",
    "expression": {
      "$firstN": {
        "n": 2
      }
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN requires input and n"
    }
  },
  {
    "id": "$firstN omit n",
    "operator": "$firstN",
    "kind": "omitted named argument",
    "operand": "n",
    "expression": {
      "$firstN": {
        "input": [
          3,
          1,
          2
        ]
      }
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN requires input and n"
    }
  },
  {
    "id": "$firstN empty arguments",
    "operator": "$firstN",
    "kind": "empty arguments",
    "operand": "all",
    "expression": {
      "$firstN": []
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN requires input and n"
    }
  },
  {
    "id": "$firstN unknown option",
    "operator": "$firstN",
    "kind": "unknown option",
    "operand": "all",
    "expression": {
      "$firstN": {
        "unexpected": 1
      }
    },
    "input": {},
    "srotax": {
      "error": "IllegalArgumentException",
      "message": "$firstN requires input and n"
    }
  }
]