firefly-iii/app/tests/factories/Piggybank.php

<?php
use Carbon\Carbon;
use League\FactoryMuffin\Facade;

Facade::define(
    'Piggybank',
    [

        'account_id'    => 'factory|Account',
        'name'          => 'string',
        'targetamount'  => 'integer',
        'startdate'     => function () {
                $start = new Carbon;
                $start->startOfMonth();

                return $start;
            },
        'targetdate'    => function () {
                $end = new Carbon;
                $end->endOfMonth();

                return $end;
            },
        'repeats'       => 0,
        'rep_length'    => null,
        'rep_times'     => 0,
        'rep_every'     => 0,
        'reminder'      => null,
        'reminder_skip' => 0,
        'order'         => 1,
    ]
);