public function testConstructor()
 {
     $output = new NullOutput();
     ob_start();
     $output->write('foo');
     $buffer = ob_get_clean();
     $this->assertSame('', $buffer, '->write() does nothing (at least nothing is printed)');
     $this->assertFalse($output->isDecorated(), '->isDecorated() returns false');
 }