Testing Laravel Form Request with custom rules

I'm trying to get my head around testing (again) and in particular test a form request with a custom rule. I'm using Laravel 5.5.

My rule needs a variable from the request to compare the field value under validation.

Whilst I can get this to work in the app I can't create the test correctly and pass the values.

Here's the custom rule (stripped down to essential info):

 class TicketNumberIsNotUsed implements Rule
{
    
    public function __construct($reservation_id)
    {
        $this->reservation_id = $reservation_id;
    }



    public function passes($attribute, $value)
    {
        $ticket = TicketAudit::where('ticketnumber', '=', $value)->first();

        if($ticket) {
            return (is_null($ticket->reservation_id) || $ticket->reservation_id == $this->reservation_id ? true : false);
        }
        return false;
    }

  
    public function message()
    {
        return 'This ticket has already been used for another booking.';
    }
}

Here's the form request which uses the custom rule:

class CreateGreenFeeSaleRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return Auth::user()->hasRole('sales');
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            'play_date'=>'required',
            'am_tee'=>'required',
            'howBooked'=>'required',
            'ticket'=>[
                'required',
                'exists:ticket_audits,ticketnumber' ,
                new TicketNumberIsNotUsed($this->reservation_id)
            ] ,
            'pay_method'=>'required',
            'customer_id'=>'required:exists:customers,id'

        ];
    }

    public function messages()
    {
        return [
            'ticket.required' => 'A valid ticket is required',
            'ticket.exists'  => 'This ticket does not exist',
        ];
    }

}

and here is my test:

class CreateGreenFeeTest extends TestCase
{
    protected function setUp()
    {
        parent::setUp();

    }

    private function createAttributes()
    {
        $faker = \Faker\Factory::create();

        $attributes = [
            'play_date' => $faker->date('d/m/Y'),
            'reservation_id' => null,
            'am_tee' => $faker->time('H:m a'),
            'howBooked' => 'drop in',
            'ticket' => 905,
            'pay_method' => 'cash',
            'customer_id' => 1532
        ];

        return $attributes;


    }

    public function test_form_validation_passes()
    {
        $attributes = $this->createAttributes();
        $request = new \App\Http\Requests\CreateGreenFeeSaleRequest();
        $rules = $request->rules();
        $validator = Validator::make($attributes, $rules);#
        $passes = $validator->passes();
        $this->assertEquals(true, $passes);
    }

    public function test_form_validation_fails_unused_ticket()
    {
        $attributes = $this->createAttributes();
//        make change to a used ticket
        $attributes['ticket']=967;
        $request = new \App\Http\Requests\CreateGreenFeeSaleRequest();
        $rules = $request->rules();
        $validator = Validator::make($attributes, $rules);#
        $fails = $validator->fails();
        $this->assertEquals(true, $fails);
    }

    public function test_form_validation_passes_used_ticket_this_reservation()
    {
        $attributes = $this->createAttributes();
//        make change to a used ticket
        $attributes['ticket']=967;
        $attributes['reservation_id']=1554;
        $request = new \App\Http\Requests\CreateGreenFeeSaleRequest();
        $rules = $request->rules();
        $validator = Validator::make($attributes, $rules);#
        var_dump($validator->errors());
        $passes = $validator->passes();
        $this->assertEquals(true, $passes);
    }
}

So:

1. How do I pass the reservation_id to the custom rule from the test
2. How should I correctly mock that an authorised user is logged in?

I am struggling with tests despite hours reading and trying to learn - it doesnt stick until I can apply it - I cant apply it till I get it!! (catch 22) So any help appreciated especially on how to construct the tests properly

Thank you