[MockMvc] [OpenAPI 3.0] Type of enum parameter not picked up when $ref is used

[Illia Sorokoumov]

I'm experiencing the following problem: if in my open api definition, I have a parameter that refers to an enum, swagger-request-validation will throw an error like this:

"Unable to parse JSON - Unrecognized token 'ro': was expecting ('true', 'false' or 'null')\n at [Source: (String)\"ro\"; line: 1, column: 5]."

The work-around is to add type explicitly in addition to $ref which is totally redundant.

Steps to reproduce:

1. Declare an endpoint with a (path or query) parameter that refers to an enum from components section. For example, take a look at "Reusable Enums" from https://swagger.io/docs/specification/data-models/enums/
2. Try using openApi().isValid request matcher in Spring MockMvc test.

example definition (does not work):

parameters:
      - in: query
        name: color
        required: true
        schema:
          $ref: '#/components/schemas/Color'

example of workaround:

parameters:
      - in: query
        name: color
        required: true
        schema:
          type: string
          $ref: '#/components/schemas/Color'