Problem with swagger array of objects: validation error: None is not of type 'array'

I'm trying to make REST API with connexion but can't figure out how to set up get operation that consumes an array of objects. In the end, I need to get information about several items at once.

Using Python 3.7, connexion-2.3.0 and Swagger with OpenAPI Specification ver. 2.

My swagger file:

swagger: "2.0"
info:
  description: "This is documentation for REST api test."
  version: "1.0.0"
  title: test

consumes:
  - application/json
produces:
  - application/json

basePath: /api

paths:
  /test:
    get:
      operationId: test.test
      summary: "Just testing array."

      parameters:
        - name: query
          in: body
          schema:
            type: array
            items:
              $ref: '#/definitions/query'

      responses:
        200:
          description: All ok!

definitions:
  query:
      type: object

      required:
        - a
        - b

      properties:
        a:
          type: integer
          description: "Test propertie 1."
          example: 42

        b:
          type: string
          description: "Test propertie 2."
          example: "hi"

        c:
          type: string
          description: "Test propertie 3."
          example: "abc"

My Python file with test function:

def test(query):
    for item in query:
        print(item)

    return {'result': 'it is fine'}

Trying to pass JSON through Swagger UI:

[
  {
    "a": 42,
    "b": "hi",
    "c": "abc"
  }
]

Expected response from my test function:

{
  "result": "it is fine"
}

Actual response:

{
  "detail": "None is not of type 'array'",
  "status": 400,
  "title": "Bad Request",
  "type": "about:blank"
}