CroogoNav::activeMenu PHP Method

    public static function activeMenu($menu = null)
    {
        if ($menu === null) {
            $activeMenu = self::$_activeMenu;
        } else {
            $activeMenu = $menu;
        }
        if (!array_key_exists($activeMenu, self::$_items)) {
            self::$_items[$activeMenu] = array();
        }
        self::$_activeMenu = $activeMenu;
        return $activeMenu;
    }

 /**
  * Test multiple menu
  */
 public function testNavMultipleMenus()
 {
     CroogoNav::activeMenu('top');
     CroogoNav::add('foo', array('title' => 'foo'));
     $menus = array_keys(CroogoNav::items());
     $this->assertFalse(in_array('foo', $menus), 'foo exists in sidebar');
     $menus = array_keys(CroogoNav::items('top'));
     $this->assertTrue(in_array('foo', $menus), 'foo missing in top');
 }