laravel/config/testing/session.php

<?php

return [

	/*
	|--------------------------------------------------------------------------
	| Default Session Driver
	|--------------------------------------------------------------------------
	|
	| This option controls the default session "driver" that will be used on
	| requests. By default, we will use the lightweight native driver but
	| you may specify any of the other wonderful drivers provided here.
	|
	| Supported: "native", "cookie", "database", "apc",
	|            "memcached", "redis", "array"
	|
	*/

	'driver' => 'array',

];