Merge remote-tracking branch 'EXreaction/ticket/11413' into develop

* EXreaction/ticket/11413: (23 commits)
  [ticket/11413] Revert some cache service related changes from earlier
  [ticket/11413] Use phpbb_user in test
  [ticket/11413] $user should have been $this->user
  [ticket/11413] Fix unit tests
  [ticket/11413] Translate the error
  [ticket/11413] Rename file to something more helpful
  [ticket/11413] Remove remaining irrelevant code to this PR
  [ticket/11413] Remove mock sql_insert_buffer.php (not relevant to PR)
  [ticket/11413] Remove conversion of user_notifications
  [ticket/11413] Correct copyright year
  [ticket/11413] Remove changes for ticket 11420 from this branch
  [ticket/11413] Include mock class
  [ticket/11413] Don't use the database for the convert test
  [ticket/11413] Test get_notification_type_id and _ids functions
  [ticket/11413] Use sql_insert_buffer
  [ticket/11413] Create test for notification conversion
  [ticket/11413] Fix test fixtures and tests
  [ticket/11413] Fix some more tests
  [ticket/11413] Fix notification tests
  [ticket/11413] Prevent recursive function calls
  ...

phpBB/language/en/common.php

@@ -424,6 +424,7 @@ $lang = array_merge($lang, array(
 	'NOTIFICATION_TOPIC_APPROVED'		=> 'Your topic "%2$s" in the forum "%3$s" was approved.',
 	'NOTIFICATION_TOPIC_DISAPPROVED'	=> 'Your topic "%1$s" was disapproved for reason: "%2$s".',
 	'NOTIFICATION_TOPIC_IN_QUEUE'		=> 'A new topic titled "%2$s" was posted by %1$s and needs approval.',
+	'NOTIFICATION_TYPE_NOT_EXIST'		=> 'The notification type "%s" is missing from the file system.',
 	'NOTIFY_ADMIN'				=> 'Please notify the board administrator or webmaster.',
 	'NOTIFY_ADMIN_EMAIL'		=> 'Please notify the board administrator or webmaster: <a href="mailto:%1$s">%1$s</a>',
 	'NO_ACCESS_ATTACHMENT'		=> 'You are not allowed to access this file.',