Validation of OpenAPI schema fails with unreasonable error of missing items of a schema

[Alexander Hofmeister]

Hello!
I am implementing tests to verify the response from the API against the written schema in OpenAPI. I am using RestAssured with this setup:

‌

OpenApiValidationFilter validationFilter = new OpenApiValidationFilter("src/main/resources/META-INF/openapi.yml");
RestAssured.filters(validationFilter);

The validation fails with:

com.atlassian.oai.validator.OpenApiInteractionValidator$ApiLoadException: Unable to load API spec from provided URL or payload:
    - attribute components.schemas.Error.items is missing

    at com.atlassian.oai.validator.util.OpenApiLoader.loadApi(OpenApiLoader.java:42)
    at com.atlassian.oai.validator.OpenApiInteractionValidator$Builder.build(OpenApiInteractionValidator.java:541)
    at com.atlassian.oai.validator.restassured.OpenApiValidationFilter.<init>(OpenApiValidationFilter.java:41)

This is the mentioned OpenAPI.yml

ErrorResponseBody:
  type: object
  properties:
    errors:
      type: array
      items:
        $ref: "#/components/schemas/Error"
Error:
  type: object
  additionalProperties: true
  required:
    - code
    - message
    - type
  properties:
    code:
      type: number
      format: int32
    message:
      type: string
    attributePath:
      type: string
    givenValue:
      anyOf:
        - type: string
        - type: number
        - type: boolean
        - type: array
        - type: object
    type:
      type: string
      enum:
        - UNKNOWN
        - RANGE_VIOLATION
        - ENTITY_NOT_FOUND
        - VALUE_REQUIRED
        - UNREASONABLE_CHANGE
        - INVALID_JSON
        - LENGTH_VIOLATION
        - NON_EXISTING_ENUM_VALUE
        - WRONG_FORMAT_ATTRIBUTE
        - UNKNOWN_PROPERTY
        - DUPLICATE_ENTITY
        - NOT_EXISTING_ENUM_VALUE
        - INVALID_VALUe

These are the lines in which the error is added to the result:

     if("array".equals( schema.getType()) && !(schema instanceof ArraySchema && ((ArraySchema) schema).getItems() != null)) {
            result.missing(location, "items");
      }

I debugged to the io.swagger.v3.parser.util.OpenAPIDeserializer and found out

• the created schema is a plain Schema, no ArraySchematherefore, no items exists
• the schema type is indeed array

‌

Am I missing something here? What exactly is wrong? Other test frameworks like https://www.chaijs.com/plugins/chai-openapi-response-validator/ are working fine with the same test-setup.

Regards,
Alexander

‌

[Alexander Hofmeister]

Something regarding the type: array does not work. Not clue.

  givenValue:
      anyOf:
        - type: string
        - type: number
        - type: boolean
        - type: array
        - type: object

I removed it and proceed with:

  schemas:
    AnyValue:
      description: 'Can be anything: string, number, array, object, etc., including `null`'

‌

‌

[Sven Döring]

If an array is defined, those items shall be defined, too.

Have you tried it like this?

givenValue:
      anyOf:
        - type: string
        - type: number
        - type: boolean
        - type: array
          items:
            type: object
        - type: object

‌

[James Navin]

As Sven has said - the example you’ve given is not valid according to the OpenAPI v3 spec. According to the specification the items keyword is required for type: array (https://swagger.io/specification/#schema-object)

items - Value MUST be an object and not an array. Inline or referenced schema MUST be of a Schema Object and not a standard JSON Schema. items MUST be present if the type is array.

The error you’re seeing is coming from the underlying OpenAPI parsing library.

I’ll take a look at how I can surface these errors with more information, but in the meantime the correct fix is as shown by Sven.