openapi: 3.0.3
info:
  title: multipart/form-data schema object
  version: 0.0.1
paths:
  /test:
    post:
      requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                file:
                  type: string
                  format: binary
                parameters:
                  "$ref": "#/components/schemas/TestBody"
      responses:
        200:
          description: ok
components:
  schemas:
    TestBody:
      type: object
      properties:
        stuff:
          type: string