public function testVerbosity()
 {
     $output = new NullOutput();
     $this->assertSame(OutputInterface::VERBOSITY_QUIET, $output->getVerbosity(), '->getVerbosity() returns VERBOSITY_QUIET for NullOutput by default');
     $output->setVerbosity(OutputInterface::VERBOSITY_VERBOSE);
     $this->assertSame(OutputInterface::VERBOSITY_QUIET, $output->getVerbosity(), '->getVerbosity() always returns VERBOSITY_QUIET for NullOutput');
 }