json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "title": "Exam test options",
      "description": "Options for an Exam test.",
      "type": "object",
      "additionalProperties": false,
      "properties": {
          "qidGroups": {
              "description": "Array of QID difficulty groups, one per difficulty level of questions.",
              "type": "array",
              "items": {
                  "description": "Array of QID topic groups, one per topic of questions.",
                  "type": "array",
                  "items": {
                      "description": "Array of question IDs (QIDs) for this topic and difficulty.",
                      "type": "array",
                      "_uniqueItems": true,
                      "item": {
                          "description": "A single question ID (QID).",
                          "type": "string"
                      }
                  }
              }
          },
          "availDate": {
              "description": "The date after which the test is available for students to view.",
              "type": "string"
          },
          "nQuestions": {
              "description": "The number of questions to select for each instance of this test.",
              "type": "integer"
          },
          "timeLimitMin": {
              "description": "The number of minutes allowed for this test.",
              "type": "integer"
          },
          "text": {
              "description": "HTML text shown on the test overview page.",
              "type": "string"
          }
      }
  }