Laravel 5.5 Validation change format of response when validation fails

Question

In Laravel 5.4, we created a class that all our requests for validation inherited because we needed to customize our response.

class APIRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return false;
    }

    /**
     * Response on failure
     * 
     * @param array $errors
     * @return Response
     */
    public function response(array $errors) {
        $response = new ResponseObject();

        $response->code = ResponseObject::BAD_REQUEST;
        $response->status = ResponseObject::FAILED;
        foreach ($errors as $item) {
            array_push($response->messages, $item);
        }
        return Response::json($response);
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            //
        ];
    }
}

A sample request that would extend this is shown below

class ResultsGetTermsRequest extends APIRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            'school_id' => 'required|integer',
            'student_id' => 'required|integer',
        ];
    }
}

And then our sample response on failure would be

{
    "status": "FAILED",
    "code": "400",
    "messages": [
        [
            "The school id field is required."
        ],
        [
            "The student id field is required."
        ]
    ],
    "result": []
}

However, this doesn't work anymore with Laravel 5.5. I noticed they replaced with response method with failedValidation. This however isn't returning any response when the request isn't validated. If I un-comment the print_r, it is something is returned. It seems the only line that is never executed is the return statement. What am I missing?

 public function failedValidation(Validator $validator) {

        $errors = (new ValidationException($validator))->errors();
        $response = new ResponseObject();

        $response->code = ResponseObject::BAD_REQUEST;
        $response->status = ResponseObject::FAILED;
        foreach ($errors as $item) {
            array_push($response->messages, $item);
        }
        //print_r($response);
        return Response::json($response);
    }

Answer 1

I guess as per laravel upgrade guide we should return HttpResponseException

protected function failedValidation(Validator $validator)
{
    $errors = $validator->errors();
        $response = new ResponseObject();

        $response->code = ResponseObject::BAD_REQUEST;
        $response->status = ResponseObject::FAILED;
        foreach ($errors as $item) {
            array_push($response->messages, $item);
        }

    throw new HttpResponseException(response()->json($response));
}