{
  "_comment": [
    "Inputs only. Expectations are measured -- see record.js.",
    "The operator table itself, rather than any one operator: what an update",
    "document may be, and what happens to a name that is not in the table.",
    "This server answers `bad update` with code 2 to every one of these, which",
    "is one message covering several different questions.",
    "A `{b: 1, $set: {...}}` case was authored and then removed: the driver",
    "rejects it before it reaches a server, so there is no server answer to",
    "record and a case with no `errorCode` would assert nothing."
  ],
  "documents": [{ "_id": 1, "a": 1, "t": [1, 2] }],
  "cases": [
    {
      "description": "an unknown modifier",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$bogus": { "a": 1 } } }
    },
    {
      "description": "an unknown modifier beside a known one",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": { "b": 1 }, "$bogus": { "a": 1 } } }
    },
    {
      "description": "a known modifier whose argument is not a document",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": 1 } }
    },
    {
      "description": "an empty argument to a known modifier",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": {} } }
    },
    {
      "description": "a data field after an operator",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": { "c": 1 }, "b": 1 } }
    },
    {
      "description": "two operators writing the same field",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": { "a": 2 }, "$inc": { "a": 1 } } }
    },
    {
      "description": "$inc on a non-numeric field",
      "documents": [{ "_id": 1, "a": "x" }],
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$inc": { "a": 1 } } }
    },
    {
      "description": "$inc by a non-numeric operand",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$inc": { "a": "x" } } }
    },
    {
      "description": "$push onto a non-array field",
      "documents": [{ "_id": 1, "t": 5 }],
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$push": { "t": 1 } } }
    },
    {
      "description": "$pull on a non-array field",
      "documents": [{ "_id": 1, "t": 5 }],
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$pull": { "t": 1 } } }
    },
    {
      "description": "$unset of a field that is not there",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$unset": { "gone": "" } } }
    },
    {
      "description": "$rename onto a field that already exists",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$rename": { "a": "t" } } }
    },
    {
      "description": "$rename of a field that is not there",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$rename": { "gone": "b" } } }
    },
    {
      "description": "an update that writes nothing still reports a match",
      "operation": "updateOne",
      "arguments": { "filter": {}, "update": { "$set": { "a": 1 } } }
    }
  ]
}