[
  {
    "id": "$subPipeline example",
    "stage": "$subPipeline",
    "kind": "example",
    "pipeline": [
      {
        "$subPipeline": [
          {
            "pipeline": [
              {
                "$set": {
                  "approved": true
                }
              }
            ]
          }
        ]
      }
    ],
    "input": [
      {
        "orderId": "A"
      }
    ],
    "result": [
      {
        "orderId": "A",
        "approved": true
      }
    ]
  },
  {
    "id": "$subPipeline empty input",
    "stage": "$subPipeline",
    "kind": "empty input",
    "pipeline": [
      {
        "$subPipeline": [
          {
            "pipeline": [
              {
                "$set": {
                  "approved": true
                }
              }
            ]
          }
        ]
      }
    ],
    "input": [],
    "result": []
  },
  {
    "id": "$subPipeline invalid specification",
    "stage": "$subPipeline",
    "kind": "invalid specification",
    "pipeline": [
      {
        "$subPipeline": null
      }
    ],
    "input": [
      {
        "orderId": "A"
      }
    ],
    "error": "IllegalArgumentException",
    "message": "$subPipeline requires an array of steps"
  },
  {
    "id": "$subPipeline missing resolver",
    "stage": "$subPipeline",
    "kind": "missing resolver",
    "pipeline": [
      {
        "$subPipeline": [
          {
            "ref": "unknown"
          }
        ]
      }
    ],
    "input": [
      {
        "orderId": "A"
      }
    ],
    "error": "IllegalArgumentException",
    "message": "Unknown pinned sub-pipeline: unknown"
  }
]