Test ViewHelper for https://review.typo3.org/40646

BoolViewHelper

<?php
namespace Acme\MyPackage\ViewHelpers;

class BoolViewHelper extends \TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper {
  /**
   * @param bool|NULL $foo
   * @return string
   */
  public function render($foo = NULL) {
    $result = 'Maybe';
    if ($foo === TRUE) {
      $result = 'Yes';
    }
    if ($foo === FALSE) {
      $result = 'No';
    }
    return sprintf('Do we care? %s.', $result);
  }
}