diff --git a/phpBB/phpbb/notification/type/mention.php b/phpBB/phpbb/notification/type/mention.php
index 2dda929d5b..fad31b9912 100644
--- a/phpBB/phpbb/notification/type/mention.php
+++ b/phpBB/phpbb/notification/type/mention.php
@@ -13,22 +13,22 @@
 
 namespace phpbb\notification\type;
 
+use phpbb\textformatter\s9e\mention_helper;
+
 /**
 * Post mentioning notifications class
 * This class handles notifying users when they have been mentioned in a post
 */
 
-class mention extends \phpbb\notification\type\post
+class mention extends post
 {
 	/**
-	* @var \phpbb\textformatter\s9e\mention_helper
+	* @var mention_helper
 	*/
 	protected $helper;
 
 	/**
-	* Get notification type name
-	*
-	* @return string
+	* {@inheritDoc}
 	*/
 	public function get_type()
 	{
@@ -36,39 +36,29 @@ class mention extends \phpbb\notification\type\post
 	}
 
 	/**
-	* Language key used to output the text
-	*
-	* @var string
-	*/
+	 * {@inheritDoc}
+	 */
 	protected $language_key = 'NOTIFICATION_MENTION';
 
 	/**
-	* Notification option data (for outputting to the user)
-	*
-	* @var bool|array False if the service should use it's default data
-	* 					Array of data (including keys 'id', 'lang', and 'group')
-	*/
-	static public $notification_option = array(
+	 * {@inheritDoc}
+	 */
+	public static $notification_option = [
 		'lang'	=> 'NOTIFICATION_TYPE_MENTION',
 		'group'	=> 'NOTIFICATION_GROUP_POSTING',
-	);
+	];
 
 	/**
-	* Is available
-	*/
+	 * {@inheritDoc}
+	 */
 	public function is_available()
 	{
 		return $this->config['allow_mentions'] && $this->auth->acl_get('u_mention');
 	}
 
 	/**
-	* Find the users who want to receive notifications
-	*
-	* @param array $post Data from submit_post
-	* @param array $options Options for finding users for notification
-	*
-	* @return array
-	*/
+	 * {@inheritDoc}
+	 */
 	public function find_users_for_notification($post, $options = array())
 	{
 		$options = array_merge(array(
@@ -128,7 +118,7 @@ class mention extends \phpbb\notification\type\post
 	}
 
 	/**
-	* {inheritDoc}
+	* {@inheritDoc}
 	*/
 	public function get_redirect_url()
 	{
@@ -136,20 +126,16 @@ class mention extends \phpbb\notification\type\post
 	}
 
 	/**
-	* Get email template
-	*
-	* @return string|bool
-	*/
+	 * {@inheritDoc}
+	 */
 	public function get_email_template()
 	{
 		return 'mention';
 	}
 
 	/**
-	* Get email template variables
-	*
-	* @return array
-	*/
+	 * {@inheritDoc}
+	 */
 	public function get_email_template_variables()
 	{
 		$user_data = $this->user_loader->get_user($this->get_data('poster_id'));
@@ -162,9 +148,9 @@ class mention extends \phpbb\notification\type\post
 	/**
 	* Set the helper service used to retrieve mentioned used
 	*
-	* @param \phpbb\textformatter\s9e\mention_helper $helper
+	* @param mention_helper $helper
 	*/
-	public function set_helper(\phpbb\textformatter\s9e\mention_helper $helper)
+	public function set_helper(mention_helper $helper): void
 	{
 		$this->helper = $helper;
 	}
diff --git a/tests/mention/controller_test.php b/tests/mention/controller_test.php
index 3b50731791..2e52c0cea7 100644
--- a/tests/mention/controller_test.php
+++ b/tests/mention/controller_test.php
@@ -92,10 +92,12 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 
 		$request->expects($this->any())
 				->method('is_ajax')
-				->willReturn(true)
-		;
+				->willReturn(true);
+		$avatar_helper = $this->getMockBuilder('\phpbb\avatar\helper')
+			->disableOriginalConstructor()
+			->getMock();
 
-		$user_loader = new \phpbb\user_loader($db, $phpbb_root_path, $phpEx, USERS_TABLE);
+		$user_loader = new \phpbb\user_loader($avatar_helper, $db, $phpbb_root_path, $phpEx, USERS_TABLE);
 
 		// Container
 		$phpbb_container = new ContainerBuilder();
@@ -113,6 +115,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 		$phpbb_container->set('request', $request);
 		$phpbb_container->set('group_helper', new \phpbb\group\helper(
 			$this->getMockBuilder('\phpbb\auth\auth')->disableOriginalConstructor()->getMock(),
+			$avatar_helper,
 			$cache,
 			$config,
 			new \phpbb\language\language(
@@ -142,6 +145,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 		);
 		$phpbb_container->setParameter('core.root_path', $phpbb_root_path);
 		$phpbb_container->setParameter('core.php_ext', $phpEx);
+		$phpbb_container->addCompilerPass(new phpbb\di\pass\markpublic_pass());
 		$phpbb_container->compile();
 
 		// Mention Sources
@@ -172,7 +176,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 7,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -205,7 +209,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -216,7 +220,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -227,7 +231,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 2,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -238,7 +242,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 3,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -249,7 +253,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 4,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -260,7 +264,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -271,7 +275,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -282,7 +286,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 7,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -293,7 +297,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 8,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -304,7 +308,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 9,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -331,7 +335,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 7,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -364,7 +368,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -375,7 +379,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -386,7 +390,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 4,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -397,7 +401,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 3,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 5,
@@ -408,7 +412,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 2,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -419,7 +423,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 3,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -430,7 +434,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 4,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -441,7 +445,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -452,7 +456,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -463,7 +467,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 7,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -474,7 +478,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 8,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -485,7 +489,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 9,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -512,7 +516,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -523,7 +527,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 1,
@@ -534,7 +538,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 5,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -545,7 +549,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 6,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -556,7 +560,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 8,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -567,7 +571,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 9,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -578,7 +582,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 10,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -589,7 +593,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 11,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -605,7 +609,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 8,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -616,7 +620,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 9,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -627,7 +631,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 10,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -638,7 +642,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 						'id'       => 11,
 						'avatar'   => [
 							'type' => 'user',
-							'img'  => '',
+							'img'  => [],
 						],
 						'rank'     => '',
 						'priority' => 0,
@@ -653,7 +657,7 @@ class phpbb_mention_controller_test extends phpbb_database_test_case
 					'id'       => 9,
 					'avatar'   => [
 						'type' => 'user',
-						'img'  => '',
+						'img'  => [],
 					],
 					'rank'     => '',
 					'priority' => 0,