testing commands in Symfony2

I want to write the tests for my console command. But my knowledge of testing is pretty pure. So I have the command what get the file from bundle, and sets values of file into memcached. For memcached I wrote myself wrapper, and declare it as service. So I need to extend my test from KernelTestCase or \PHPUnit_Framework_TestCase. And I need to do all by hands(like create array, set it into memcached for simulate work of command) or I just need use Symfony\Component\Console\Tester\CommandTester; ? Can somebody help me? Thanks!