You can find out what services are registered with the container using the console.
php artisan debug:container
composer require bernardosecades/laravel-debug-container
Example:
if ( env('APP_ENV') === 'development' ) {
$app->register(\BernardoSecades\Laravel\DebugContainer\DebugContainerServiceProvider::class);
}
php artisan debug:container
./vendor/bin/phpunit