{
  "$defs": {
    "TestNullable": {
      "additionalProperties": false,
      "properties": {
        "child1": {
          "oneOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ]
        }
      },
      "required": [
        "child1"
      ],
      "type": "object"
    }
  },
  "$id": "https://github.com/invopop/jsonschema/test-nullable",
  "$ref": "#/$defs/TestNullable",
  "$schema": "https://json-schema.org/draft/2020-12/schema"
}