実行できないコマンド：bin/console customize:test
実行可能コマンド：bin/console cache:clear --no-warmup

■カスタマイズファイル

namespace Customize\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Style\SymfonyStyle;

/**
* Remind cron.
*/
class RemindCommand extends Command
{
protected static $defaultName = 'customize:test';

protected function execute(InputInterface $input, OutputInterface $output)
{
$io = new SymfonyStyle($input, $output);

// hello worldを表示
$io->success('hello world');

}
}

■エラー内容

PHP Fatal error: Uncaught Symfony\Component\Debug\Exception\ClassNotFoundException: Attempted to load class "Generator" from namespace "Eccube\Tests\Fixture".
Did you forget a "use" statement for e.g. "Symfony\Bundle\MakerBundle\Generator" or "Sensio\Bundle\GeneratorBundle\Generator\Generator"? in /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/getGeneratorService.php:8
Stack trace:
#0 /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/EccubeDevDebugProjectContainer.php(2267): require()
#1 /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/getGenerateDummyDataCommandService.php(11): ContainerHjlmhhm\EccubeDevDebugProjectContainer->load('getGeneratorSer...')
#2 /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/EccubeDevDebugProjectContainer.php(2267): require('/Users/XXXXXX...')
#3 /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/getConsole_CommandLoaderService.php(24): ContainerHjlmhhm\EccubeDevDebugProjectContainer->load('getGenerateDumm...')
#4 /Users/ in /Users/XXXXXX/project/XXXXXX/var/cache/dev/ContainerHjlmhhm/getGeneratorService.php on line 8