/**
  * Create a member and group with the given permission code, and log in with it.
  * Returns the member ID.
  *
  * @param string|array $permCode Either a permission, or list of permissions
  * @return int Member ID
  */
 public function logInWithPermission($permCode = "ADMIN")
 {
     if (is_array($permCode)) {
         $permArray = $permCode;
         $permCode = implode('.', $permCode);
     } else {
         $permArray = array($permCode);
     }
     // Check cached member
     if (isset($this->cache_generatedMembers[$permCode])) {
         $member = $this->cache_generatedMembers[$permCode];
     } else {
         // Generate group with these permissions
         $group = Group::create();
         $group->Title = "{$permCode} group";
         $group->write();
         // Create each individual permission
         foreach ($permArray as $permArrayItem) {
             $permission = Permission::create();
             $permission->Code = $permArrayItem;
             $permission->write();
             $group->Permissions()->add($permission);
         }
         $member = DataObject::get_one('SilverStripe\\Security\\Member', array('"Member"."Email"' => "{$permCode}@example.org"));
         if (!$member) {
             $member = Member::create();
         }
         $member->FirstName = $permCode;
         $member->Surname = "User";
         $member->Email = "{$permCode}@example.org";
         $member->write();
         $group->Members()->add($member);
         $this->cache_generatedMembers[$permCode] = $member;
     }
     $member->logIn();
     return $member->ID;
 }