From 091b458c52de1037652e618b93a8594daf78a07a Mon Sep 17 00:00:00 2001
From: "Eloy Lafuente (stronk7)" <stronk7@moodle.org>
Date: Thu, 30 May 2024 12:15:15 +0200
Subject: [PATCH] MDL-81522 phpunit: Add missing void return type to all tests
 #2

This commit includes more changes, all them also adding the :void
return type to unit tests missing them.

The difference is that all these changes, while also detected
perfectly by the moodle.PHPUnit.TestReturnType sniff, were not
auto-fixed (like the previous commit ones), because all them
do include some "return" statement and, for safety, we don't
fix them.

All the cases have been visually inspected and confirmed that
the existing "return" statements always belong to anon
functions within the test body and not the test own return statement.
---
 .../tests/expired_contexts_test.php           |  8 +++----
 .../tests/manager_observer_test.php           |  2 +-
 .../generator/tests/maketestcourse_test.php   |  2 +-
 admin/tool/policy/tests/api_test.php          |  2 +-
 cache/tests/administration_helper_test.php    |  2 +-
 calendar/tests/event_factory_test.php         | 10 ++++----
 calendar/tests/event_vault_test.php           | 12 +++++-----
 calendar/tests/externallib_test.php           |  4 ++--
 calendar/tests/std_proxy_test.php             |  8 +++----
 competency/tests/privacy/provider_test.php    |  2 +-
 course/tests/backup/restore_test.php          |  2 +-
 ..._content_item_readonly_repository_test.php |  2 +-
 course/tests/category_test.php                |  2 +-
 .../content_item_readonly_repository_test.php |  2 +-
 course/tests/courselib_test.php               | 14 +++++------
 course/tests/externallib_test.php             |  8 +++----
 .../published_resource_repository_test.php    |  4 ++--
 .../resource_link_repository_test.php         |  4 ++--
 .../ltiadvantage/task/sync_members_test.php   |  2 +-
 .../task/sync_tool_grades_test.php            |  6 ++---
 enrol/tests/enrollib_test.php                 |  2 +-
 lib/dml/tests/dml_test.php                    |  2 +-
 lib/filebrowser/tests/file_browser_test.php   | 10 ++++----
 lib/filestorage/tests/file_storage_test.php   |  2 +-
 lib/form/tests/filetypes_util_test.php        |  2 +-
 lib/phpunit/tests/phpunit_dataset_test.php    |  2 +-
 lib/tests/authlib_test.php                    |  2 +-
 lib/tests/core_media_player_native_test.php   |  2 +-
 lib/tests/curl_security_helper_test.php       |  2 +-
 lib/tests/grouplib_test.php                   |  2 +-
 lib/tests/navigation/output/primary_test.php  |  2 +-
 .../mustache_helper_collection_test.php       |  2 +-
 lib/tests/questionlib_test.php                |  2 +-
 lib/tests/task/database_logger_test.php       |  2 +-
 login/tests/login_lib_test.php                |  2 +-
 media/player/html5audio/tests/player_test.php |  2 +-
 media/player/html5video/tests/player_test.php |  2 +-
 message/tests/api_test.php                    |  6 ++---
 message/tests/externallib_test.php            | 10 ++++----
 message/tests/privacy/provider_test.php       | 10 ++++----
 .../tests/external/start_submission_test.php  | 10 ++++----
 mod/assign/tests/externallib_test.php         |  2 +-
 mod/assign/tests/lib_test.php                 |  2 +-
 .../tests/external/get_recordings_test.php    |  2 +-
 mod/bigbluebuttonbn/tests/lib_test.php        |  4 ++--
 .../local/proxy/recording_proxy_test.php      |  4 ++--
 .../output/recording_row_playback_test.php    |  2 +-
 mod/choice/tests/lib_test.php                 |  4 ++--
 mod/data/tests/lib_test.php                   |  4 ++--
 mod/data/tests/manager_test.php               |  6 ++---
 mod/data/tests/preset_test.php                |  2 +-
 mod/feedback/tests/lib_test.php               |  2 +-
 .../tests/builders_exported_posts_test.php    | 12 +++++-----
 mod/forum/tests/entities_sorter_test.php      |  4 ++--
 mod/forum/tests/privacy/provider_test.php     |  6 ++---
 mod/forum/tests/vaults_forum_test.php         |  2 +-
 .../get_h5pactivities_by_courses_test.php     |  2 +-
 mod/lesson/tests/lib_test.php                 |  4 ++--
 .../tests/calendar_event_modified_test.php    |  2 +-
 .../local_structure_slot_random_test.php      |  2 +-
 mod/scorm/tests/externallib_test.php          |  2 +-
 mod/scorm/tests/lib_test.php                  |  4 ++--
 mod/wiki/tests/privacy/provider_test.php      |  8 +++----
 privacy/tests/moodle_content_writer_test.php  |  4 ++--
 question/tests/externallib_test.php           |  4 ++--
 .../calculated/tests/question_type_test.php   |  2 +-
 .../multianswer/tests/question_type_test.php  |  2 +-
 .../contentbank/tests/search/search_test.php  |  2 +-
 repository/dropbox/tests/api_test.php         |  6 ++---
 tag/tests/privacy/provider_test.php           |  2 +-
 tag/tests/taglib_test.php                     | 24 +++++++++----------
 user/tests/userlib_test.php                   |  2 +-
 72 files changed, 153 insertions(+), 153 deletions(-)

diff --git a/admin/tool/dataprivacy/tests/expired_contexts_test.php b/admin/tool/dataprivacy/tests/expired_contexts_test.php
index 4b8680c4d7a7e..d851000ba6a0f 100644
--- a/admin/tool/dataprivacy/tests/expired_contexts_test.php
+++ b/admin/tool/dataprivacy/tests/expired_contexts_test.php
@@ -867,7 +867,7 @@ public function test_process_user_context_with_override_unexpired_role(): void {
     /**
      * Ensure that a module context previously flagged as approved is removed with appropriate unexpiredroles kept.
      */
-    public function test_process_course_context_with_override_unexpired_role() {
+    public function test_process_course_context_with_override_unexpired_role(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -955,7 +955,7 @@ public function test_process_course_context_with_override_unexpired_role() {
     /**
      * Ensure that a module context previously flagged as approved is removed with appropriate expiredroles kept.
      */
-    public function test_process_course_context_with_override_expired_role() {
+    public function test_process_course_context_with_override_expired_role(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -1043,7 +1043,7 @@ public function test_process_course_context_with_override_expired_role() {
     /**
      * Ensure that a module context previously flagged as approved is removed with appropriate expiredroles kept.
      */
-    public function test_process_course_context_with_user_in_both_lists() {
+    public function test_process_course_context_with_user_in_both_lists(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -1132,7 +1132,7 @@ public function test_process_course_context_with_user_in_both_lists() {
     /**
      * Ensure that a module context previously flagged as approved is removed with appropriate expiredroles kept.
      */
-    public function test_process_course_context_with_user_in_both_lists_expired() {
+    public function test_process_course_context_with_user_in_both_lists_expired(): void {
         global $DB;
         $this->resetAfterTest();
 
diff --git a/admin/tool/dataprivacy/tests/manager_observer_test.php b/admin/tool/dataprivacy/tests/manager_observer_test.php
index 7296eb181d1eb..4902dcd2c8494 100644
--- a/admin/tool/dataprivacy/tests/manager_observer_test.php
+++ b/admin/tool/dataprivacy/tests/manager_observer_test.php
@@ -32,7 +32,7 @@ class manager_observer_test extends data_privacy_testcase {
     /**
      * Ensure that when users are configured as DPO, they are sent an message upon failure.
      */
-    public function test_handle_component_failure() {
+    public function test_handle_component_failure(): void {
         $this->resetAfterTest();
 
         // Create another user who is not a DPO.
diff --git a/admin/tool/generator/tests/maketestcourse_test.php b/admin/tool/generator/tests/maketestcourse_test.php
index a257a42262c1e..11670ec10f192 100644
--- a/admin/tool/generator/tests/maketestcourse_test.php
+++ b/admin/tool/generator/tests/maketestcourse_test.php
@@ -30,7 +30,7 @@ class maketestcourse_test extends \advanced_testcase {
     /**
      * Creates a small test course and checks all the components have been put in place.
      */
-    public function test_make_xs_course() {
+    public function test_make_xs_course(): void {
         global $DB;
 
         $this->resetAfterTest();
diff --git a/admin/tool/policy/tests/api_test.php b/admin/tool/policy/tests/api_test.php
index 7a7605a23e6cc..ee4973f2b3b53 100644
--- a/admin/tool/policy/tests/api_test.php
+++ b/admin/tool/policy/tests/api_test.php
@@ -193,7 +193,7 @@ public function test_policy_sortorder(): void {
     /**
      * Test that list of policies can be filtered by audience
      */
-    public function test_list_policies_audience() {
+    public function test_list_policies_audience(): void {
         $this->resetAfterTest();
         $this->setAdminUser();
 
diff --git a/cache/tests/administration_helper_test.php b/cache/tests/administration_helper_test.php
index b61cc087a8a00..49b3dd1a06fd3 100644
--- a/cache/tests/administration_helper_test.php
+++ b/cache/tests/administration_helper_test.php
@@ -60,7 +60,7 @@ public static function tearDownAfterClass(): void {
     /**
      * Test the numerous summaries the helper can produce.
      */
-    public function test_get_summaries() {
+    public function test_get_summaries(): void {
         // First the preparation.
         $config = cache_config_writer::instance();
         $this->assertTrue($config->add_store_instance('summariesstore', 'file'));
diff --git a/calendar/tests/event_factory_test.php b/calendar/tests/event_factory_test.php
index 3fabf8e855920..b571aa7ea90ff 100644
--- a/calendar/tests/event_factory_test.php
+++ b/calendar/tests/event_factory_test.php
@@ -85,7 +85,7 @@ public function test_create_instance(
     /**
      * Test invalid callback exception.
      */
-    public function test_invalid_action_callback() {
+    public function test_invalid_action_callback(): void {
         $this->resetAfterTest(true);
         $this->setAdminUser();
         $event = $this->create_event();
@@ -135,7 +135,7 @@ function () {
     /**
      * Test invalid callback exception.
      */
-    public function test_invalid_visibility_callback() {
+    public function test_invalid_visibility_callback(): void {
         $this->resetAfterTest(true);
         $this->setAdminUser();
         $event = $this->create_event();
@@ -185,7 +185,7 @@ function () {
     /**
      * Test invalid callback exception.
      */
-    public function test_invalid_bail_callback() {
+    public function test_invalid_bail_callback(): void {
         $this->resetAfterTest(true);
         $this->setAdminUser();
         $event = $this->create_event();
@@ -235,7 +235,7 @@ function () {
     /**
      * Test the factory's course cache.
      */
-    public function test_course_cache() {
+    public function test_course_cache(): void {
         $this->resetAfterTest(true);
         $this->setAdminUser();
         $course = self::getDataGenerator()->create_course();
@@ -288,7 +288,7 @@ function () {
     /**
      * Test the factory's module cache.
      */
-    public function test_module_cache() {
+    public function test_module_cache(): void {
         $this->resetAfterTest(true);
         $this->setAdminUser();
         $course = self::getDataGenerator()->create_course();
diff --git a/calendar/tests/event_vault_test.php b/calendar/tests/event_vault_test.php
index d03ab45ea80be..c8c29368325b5 100644
--- a/calendar/tests/event_vault_test.php
+++ b/calendar/tests/event_vault_test.php
@@ -196,7 +196,7 @@ public function test_get_action_events_by_timesort_between_time_after_event(): v
      * provided timesort values and the last seen event can be provided to
      * get paginated results.
      */
-    public function test_get_action_events_by_timesort_between_time_skip_even_records() {
+    public function test_get_action_events_by_timesort_between_time_skip_even_records(): void {
         $this->resetAfterTest(true);
         $this->setAdminuser();
 
@@ -247,7 +247,7 @@ public function test_get_action_events_by_timesort_between_time_skip_even_record
      * number of events requested has been satisfied. In this case the first
      * five events are rejected so it should require two database requests.
      */
-    public function test_get_action_events_by_timesort_between_time_skip_first_records() {
+    public function test_get_action_events_by_timesort_between_time_skip_first_records(): void {
         $this->resetAfterTest(true);
         $this->setAdminuser();
 
@@ -423,7 +423,7 @@ public function test_get_action_events_by_timesort_non_consecutive_ids(): void {
      * - A user in group B should see only the B override
      * - A user in both A and B should see both
      */
-    public function test_get_action_events_by_timesort_with_identical_group_override_priorities() {
+    public function test_get_action_events_by_timesort_with_identical_group_override_priorities(): void {
         $this->resetAfterTest();
         $this->setAdminuser();
 
@@ -804,7 +804,7 @@ public function test_get_action_events_by_course_between_time_after_event(): voi
      * provided timesort values and the last seen event can be provided to
      * get paginated results.
      */
-    public function test_get_action_events_by_course_between_time_skip_even_records() {
+    public function test_get_action_events_by_course_between_time_skip_even_records(): void {
         $user = $this->getDataGenerator()->create_user();
         $course1 = $this->getDataGenerator()->create_course();
         $course2 = $this->getDataGenerator()->create_course();
@@ -870,7 +870,7 @@ public function test_get_action_events_by_course_between_time_skip_even_records(
      * number of events requested has been satisfied. In this case the first
      * five events are rejected so it should require two database requests.
      */
-    public function test_get_action_events_by_course_between_time_skip_first_records() {
+    public function test_get_action_events_by_course_between_time_skip_first_records(): void {
         $user = $this->getDataGenerator()->create_user();
         $course1 = $this->getDataGenerator()->create_course();
         $course2 = $this->getDataGenerator()->create_course();
@@ -1080,7 +1080,7 @@ public function test_get_action_events_by_course_non_consecutive_ids(): void {
      * - A user in group B should see only the B override
      * - A user in both A and B should see both
      */
-    public function test_get_action_events_by_course_with_identical_group_override_priorities() {
+    public function test_get_action_events_by_course_with_identical_group_override_priorities(): void {
         $this->resetAfterTest();
         $this->setAdminuser();
 
diff --git a/calendar/tests/externallib_test.php b/calendar/tests/externallib_test.php
index 33ee8a22d90b2..e987aaa7eac08 100644
--- a/calendar/tests/externallib_test.php
+++ b/calendar/tests/externallib_test.php
@@ -1425,7 +1425,7 @@ public function test_get_calendar_action_events_by_course_with_search(): void {
      * Test that get_action_events_by_courses will return a list of events for each
      * course you provided as long as the user is enrolled in the course.
      */
-    public function test_get_action_events_by_courses() {
+    public function test_get_action_events_by_courses(): void {
         $user = $this->getDataGenerator()->create_user();
         $course1 = $this->getDataGenerator()->create_course();
         $course2 = $this->getDataGenerator()->create_course();
@@ -1558,7 +1558,7 @@ public function test_get_action_events_by_courses() {
     /**
      * Test get_action_events_by_courses with search feature
      */
-    public function test_get_action_events_by_courses_with_search() {
+    public function test_get_action_events_by_courses_with_search(): void {
         // Generate data.
         $user = $this->getDataGenerator()->create_user();
         $course1 = $this->getDataGenerator()->create_course();
diff --git a/calendar/tests/std_proxy_test.php b/calendar/tests/std_proxy_test.php
index 9658a6098faae..af3080df97906 100644
--- a/calendar/tests/std_proxy_test.php
+++ b/calendar/tests/std_proxy_test.php
@@ -54,7 +54,7 @@ public function setUp(): void {
      * @param string $member   Object member to retrieve.
      * @param mixed  $expected Expected value of member.
      */
-    public function test_proxy($id, $member, $expected) {
+    public function test_proxy($id, $member, $expected): void {
         $proxy = new std_proxy($id, function($id) {
             return $this->objects[$id];
         });
@@ -70,7 +70,7 @@ public function test_proxy($id, $member, $expected) {
      * @param string $member      Object member to retrieve.
      * @param mixed  $storedvalue Value as would be stored externally.
      */
-    public function test_base_values($id, $member, $storedvalue) {
+    public function test_base_values($id, $member, $storedvalue): void {
         $proxy = new std_proxy(
             $id,
             function($id) {
@@ -89,7 +89,7 @@ function($id) {
      * @dataProvider get_set_testcases
      * @param int $id ID of the object being proxied.
      */
-    public function test_get_invalid_member($id) {
+    public function test_get_invalid_member($id): void {
         $proxy = new std_proxy($id, function($id) {
             return $this->objects[$id];
         });
@@ -104,7 +104,7 @@ public function test_get_invalid_member($id) {
      * @dataProvider get_set_testcases
      * @param int $id Object ID.
      */
-    public function test_get_proxied_instance($id) {
+    public function test_get_proxied_instance($id): void {
         $proxy = new std_proxy($id, function($id) {
             return $this->objects[$id];
         });
diff --git a/competency/tests/privacy/provider_test.php b/competency/tests/privacy/provider_test.php
index 2e8f39aa8ea83..dff9fe5cf1da6 100644
--- a/competency/tests/privacy/provider_test.php
+++ b/competency/tests/privacy/provider_test.php
@@ -1999,7 +1999,7 @@ public function test_export_data_for_user_with_related_learning_plans(): void {
         $this->assert_exported_comments(['Hi.'], $data->comments);
     }
 
-    public function test_export_data_for_user_with_related_competencies() {
+    public function test_export_data_for_user_with_related_competencies(): void {
         $path = [
             get_string('competencies', 'core_competency'),
             get_string('privacy:path:relatedtome', 'core_competency'),
diff --git a/course/tests/backup/restore_test.php b/course/tests/backup/restore_test.php
index 26ebb90dc3175..bfd98f5752bc0 100644
--- a/course/tests/backup/restore_test.php
+++ b/course/tests/backup/restore_test.php
@@ -387,7 +387,7 @@ public function test_restore_course_info_in_new_course(): void {
         $this->assertEquals($startdate, $c2->startdate);
     }
 
-    public function test_restore_course_with_users() {
+    public function test_restore_course_with_users(): void {
         global $DB;
         $this->resetAfterTest();
         $this->setAdminUser();
diff --git a/course/tests/caching_content_item_readonly_repository_test.php b/course/tests/caching_content_item_readonly_repository_test.php
index ffb76c639018f..9ea96b426f413 100644
--- a/course/tests/caching_content_item_readonly_repository_test.php
+++ b/course/tests/caching_content_item_readonly_repository_test.php
@@ -39,7 +39,7 @@ class caching_content_item_readonly_repository_test extends \advanced_testcase {
     /**
      * Test verifying that content items are cached and returned from the cache in subsequent same-request calls.
      */
-    public function test_find_all_for_course() {
+    public function test_find_all_for_course(): void {
         $this->resetAfterTest();
         global $DB;
 
diff --git a/course/tests/category_test.php b/course/tests/category_test.php
index c1ec14a69975b..f17709fce11fd 100644
--- a/course/tests/category_test.php
+++ b/course/tests/category_test.php
@@ -751,7 +751,7 @@ public function test_course_contacts(): void {
         $CFG->coursecontact = $oldcoursecontact;
     }
 
-    public function test_course_contacts_with_duplicates() {
+    public function test_course_contacts_with_duplicates(): void {
         global $DB, $CFG;
 
         set_config('coursecontactduplicates', true);
diff --git a/course/tests/content_item_readonly_repository_test.php b/course/tests/content_item_readonly_repository_test.php
index 84406076c093b..8a6b30aff5650 100644
--- a/course/tests/content_item_readonly_repository_test.php
+++ b/course/tests/content_item_readonly_repository_test.php
@@ -76,7 +76,7 @@ public function test_find_all_for_course_hidden_module(): void {
     /**
      * Test confirming that all content items can be fetched, even those which require certain caps when in a course.
      */
-    public function test_find_all() {
+    public function test_find_all(): void {
         $this->resetAfterTest();
 
         global $DB, $CFG;
diff --git a/course/tests/courselib_test.php b/course/tests/courselib_test.php
index 7fdaf62202fb3..45338180d3889 100644
--- a/course/tests/courselib_test.php
+++ b/course/tests/courselib_test.php
@@ -4582,7 +4582,7 @@ public function get_course_classify_courses_for_timeline_test_cases() {
      * @param array $coursesdata Courses to create
      * @param array $expected Expected test results.
      */
-    public function test_course_classify_courses_for_timeline($coursesdata, $expected) {
+    public function test_course_classify_courses_for_timeline($coursesdata, $expected): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
 
@@ -4723,7 +4723,7 @@ public function test_course_get_enrolled_courses_for_logged_in_user(
         $offset,
         $expecteddbqueries,
         $expectedresult
-    ) {
+    ): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -4908,7 +4908,7 @@ public function get_course_filter_courses_by_timeline_classification_test_cases(
     /**
      * Test the course_get_enrolled_courses_for_logged_in_user_from_search function.
      */
-    public function test_course_get_enrolled_courses_for_logged_in_user_from_search() {
+    public function test_course_get_enrolled_courses_for_logged_in_user_from_search(): void {
         global $DB;
 
         // Set up.
@@ -5021,7 +5021,7 @@ public function test_course_filter_courses_by_timeline_classification(
         $offset,
         $expectedcourses,
         $expectedprocessedcount
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
 
@@ -5242,7 +5242,7 @@ public function test_course_filter_courses_by_customfield(
         $offset,
         $expectedcourses,
         $expectedprocessedcount
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
 
@@ -5487,7 +5487,7 @@ public function test_course_filter_courses_by_timeline_classification_with_hidde
         $expectedcourses,
         $expectedprocessedcount,
         $hiddencourse
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
         $student = $generator->create_user();
@@ -6983,7 +6983,7 @@ public function test_course_get_course_dates_for_user_ids(
         $enrolmentmethods,
         $enrolled,
         $expected
-    ) {
+    ): void {
         global $DB;
         $this->resetAfterTest();
 
diff --git a/course/tests/externallib_test.php b/course/tests/externallib_test.php
index a560bf98674b4..606af80929c34 100644
--- a/course/tests/externallib_test.php
+++ b/course/tests/externallib_test.php
@@ -3747,7 +3747,7 @@ public function test_get_enrolled_courses_by_timeline_classification(
         $expectednextoffset,
         $expectedexception = null,
         $searchvalue = null
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
 
@@ -3979,7 +3979,7 @@ public function test_get_enrolled_users_by_cmid(): void {
     /**
      * Verify that content items can be added to user favourites.
      */
-    public function test_add_content_item_to_user_favourites() {
+    public function test_add_content_item_to_user_favourites(): void {
         $this->resetAfterTest();
 
         $course = $this->getDataGenerator()->create_course();
@@ -4017,7 +4017,7 @@ public function test_add_content_item_to_user_favourites() {
     /**
      * Verify that content items can be removed from user favourites.
      */
-    public function test_remove_content_item_from_user_favourites() {
+    public function test_remove_content_item_from_user_favourites(): void {
         $this->resetAfterTest();
 
         $course = $this->getDataGenerator()->create_course();
@@ -4057,7 +4057,7 @@ public function test_remove_content_item_from_user_favourites() {
     /**
      * Test the web service returning course content items for inclusion in activity choosers, etc.
      */
-    public function test_get_course_content_items() {
+    public function test_get_course_content_items(): void {
         $this->resetAfterTest();
 
         $course  = self::getDataGenerator()->create_course();
diff --git a/enrol/lti/tests/local/ltiadvantage/repository/published_resource_repository_test.php b/enrol/lti/tests/local/ltiadvantage/repository/published_resource_repository_test.php
index 58bc5635d6854..9a9baac241b4e 100644
--- a/enrol/lti/tests/local/ltiadvantage/repository/published_resource_repository_test.php
+++ b/enrol/lti/tests/local/ltiadvantage/repository/published_resource_repository_test.php
@@ -98,7 +98,7 @@ protected function generate_published_resources() {
      *
      * @covers ::find_all_for_user
      */
-    public function test_find_all_for_user() {
+    public function test_find_all_for_user(): void {
         $this->resetAfterTest();
         [$user, $user2, $user3, $course, $course2, $mod, $mod2, $mod3, $mod4] = $this->generate_published_resources();
 
@@ -131,7 +131,7 @@ public function test_find_all_for_user() {
      *
      * @covers ::find_all_by_ids_for_user
      */
-    public function test_find_all_by_ids_for_user() {
+    public function test_find_all_by_ids_for_user(): void {
         $this->resetAfterTest();
         [$user, $user2, $user3, $course, $course2, $mod, $mod2, $mod3, $mod4, $coursetool, $tool, $tool2, $tool3, $tool4] =
             $this->generate_published_resources();
diff --git a/enrol/lti/tests/local/ltiadvantage/repository/resource_link_repository_test.php b/enrol/lti/tests/local/ltiadvantage/repository/resource_link_repository_test.php
index 4526cb3ab3ff1..7d69fdb412102 100644
--- a/enrol/lti/tests/local/ltiadvantage/repository/resource_link_repository_test.php
+++ b/enrol/lti/tests/local/ltiadvantage/repository/resource_link_repository_test.php
@@ -167,7 +167,7 @@ public function test_find(): void {
      *
      * @covers ::find_by_resource
      */
-    public function test_find_by_resource() {
+    public function test_find_by_resource(): void {
         $this->resetAfterTest();
         $resourcelink = $this->generate_resource_link();
         $repository = new resource_link_repository();
@@ -196,7 +196,7 @@ public function test_find_by_resource() {
      *
      * @covers ::find_by_resource_and_user
      */
-    public function test_find_by_resource_and_user() {
+    public function test_find_by_resource_and_user(): void {
         global $CFG;
         $this->resetAfterTest();
         $resourcelink = $this->generate_resource_link();
diff --git a/enrol/lti/tests/local/ltiadvantage/task/sync_members_test.php b/enrol/lti/tests/local/ltiadvantage/task/sync_members_test.php
index 3db54e83d4a49..eccca4c60091e 100644
--- a/enrol/lti/tests/local/ltiadvantage/task/sync_members_test.php
+++ b/enrol/lti/tests/local/ltiadvantage/task/sync_members_test.php
@@ -726,7 +726,7 @@ public function test_sync_non_lti_linked_user(): void {
      * @covers ::execute
      */
     public function test_sync_enrolments_and_migration(?array $legacydata, ?array $resourceconfig, array $launchdata,
-            ?array $syncmembers, array $expected) {
+            ?array $syncmembers, array $expected): void {
 
         $this->resetAfterTest();
 
diff --git a/enrol/lti/tests/local/ltiadvantage/task/sync_tool_grades_test.php b/enrol/lti/tests/local/ltiadvantage/task/sync_tool_grades_test.php
index f661e03ab0805..72b95b813ba0f 100644
--- a/enrol/lti/tests/local/ltiadvantage/task/sync_tool_grades_test.php
+++ b/enrol/lti/tests/local/ltiadvantage/task/sync_tool_grades_test.php
@@ -743,7 +743,7 @@ public function test_sync_grades_failed_service_call(): void {
      *
      * @covers ::execute
      */
-    public function test_sync_grades_coupled_lineitem() {
+    public function test_sync_grades_coupled_lineitem(): void {
         $this->resetAfterTest();
 
         [$course, $resource] = $this->create_test_environment();
@@ -817,7 +817,7 @@ public function test_sync_grades_coupled_lineitem() {
      *
      * @covers ::execute
      */
-    public function test_sync_grades_none_or_many_lineitems_activity_context() {
+    public function test_sync_grades_none_or_many_lineitems_activity_context(): void {
         $this->resetAfterTest();
 
         [$course, $resource] = $this->create_test_environment();
@@ -894,7 +894,7 @@ public function test_sync_grades_none_or_many_lineitems_activity_context() {
      *
      * @covers ::execute
      */
-    public function test_sync_grades_none_or_many_lineitems_course_context() {
+    public function test_sync_grades_none_or_many_lineitems_course_context(): void {
         $this->resetAfterTest();
 
         [$course, $tool1, $tool2, $resource] = $this->create_test_environment();
diff --git a/enrol/tests/enrollib_test.php b/enrol/tests/enrollib_test.php
index 2280c144741ba..b19530f672626 100644
--- a/enrol/tests/enrollib_test.php
+++ b/enrol/tests/enrollib_test.php
@@ -1308,7 +1308,7 @@ public function test_enrol_get_my_courses_sort_by_last_access(
         $limit,
         $offset,
         $expectedcourses
-    ) {
+    ): void {
         global $DB, $CFG;
 
         $this->resetAfterTest();
diff --git a/lib/dml/tests/dml_test.php b/lib/dml/tests/dml_test.php
index b00b1f897dba8..f93189cc40cdd 100644
--- a/lib/dml/tests/dml_test.php
+++ b/lib/dml/tests/dml_test.php
@@ -533,7 +533,7 @@ public function test_add_sql_debugging(): void {
      *
      * @covers ::add_sql_debugging
      */
-    public function test_sql_debugging_anon_class() {
+    public function test_sql_debugging_anon_class(): void {
         global $CFG;
         $CFG->debugsqltrace = 100;
 
diff --git a/lib/filebrowser/tests/file_browser_test.php b/lib/filebrowser/tests/file_browser_test.php
index 6d0123bbd077c..5044a810b46ff 100644
--- a/lib/filebrowser/tests/file_browser_test.php
+++ b/lib/filebrowser/tests/file_browser_test.php
@@ -109,7 +109,7 @@ public function setUp(): void {
     /**
      * Test "Server files" from the system context
      */
-    public function test_file_info_context_system() {
+    public function test_file_info_context_system(): void {
 
         // There is one non-empty category child and two category children.
 
@@ -126,7 +126,7 @@ public function test_file_info_context_system() {
     /**
      * Test "Server files" from the system context, hide Misc category
      */
-    public function test_file_info_context_system_hidden() {
+    public function test_file_info_context_system_hidden(): void {
 
         // Hide the course category that contains our two courses. Teacher does not have cap to view hidden categories.
         \core_course_category::get($this->course1->category)->update(['visible' => 0]);
@@ -153,7 +153,7 @@ public function test_file_info_context_system_hidden() {
     /**
      * Test "Server files" from the course category context
      */
-    public function test_file_info_context_coursecat() {
+    public function test_file_info_context_coursecat(): void {
 
         // There are two non-empty courses.
 
@@ -183,7 +183,7 @@ public function test_file_info_context_coursecat_jpg(): void {
     /**
      * Test "Server files" from the course context (course1)
      */
-    public function test_file_info_context_course_1() {
+    public function test_file_info_context_course_1(): void {
 
         $browser = get_file_browser();
         $fileinfo = $browser->get_file_info(\context_course::instance($this->course1->id));
@@ -214,7 +214,7 @@ public function test_file_info_context_course_1() {
     /**
      * Test "Server files" from the course context (course1)
      */
-    public function test_file_info_context_course_2() {
+    public function test_file_info_context_course_2(): void {
 
         // 2. Start from the course level.
         $browser = get_file_browser();
diff --git a/lib/filestorage/tests/file_storage_test.php b/lib/filestorage/tests/file_storage_test.php
index d5acb1c931b17..2c1500942b9e8 100644
--- a/lib/filestorage/tests/file_storage_test.php
+++ b/lib/filestorage/tests/file_storage_test.php
@@ -540,7 +540,7 @@ private function setup_three_private_files() {
      *
      * @covers ::get_area_files
      */
-    public function test_get_area_files() {
+    public function test_get_area_files(): void {
         $user = $this->setup_three_private_files();
         $fs = get_file_storage();
 
diff --git a/lib/form/tests/filetypes_util_test.php b/lib/form/tests/filetypes_util_test.php
index d932964423f33..f1cd3d5f7c7f6 100644
--- a/lib/form/tests/filetypes_util_test.php
+++ b/lib/form/tests/filetypes_util_test.php
@@ -273,7 +273,7 @@ public function test_get_not_listed(): void {
     /**
      * Test populating the tree for the browser.
      */
-    public function test_data_for_browser() {
+    public function test_data_for_browser(): void {
 
         $this->resetAfterTest(true);
         $util = new filetypes_util();
diff --git a/lib/phpunit/tests/phpunit_dataset_test.php b/lib/phpunit/tests/phpunit_dataset_test.php
index c0c1cd64d6f60..56dc9a29cc0f4 100644
--- a/lib/phpunit/tests/phpunit_dataset_test.php
+++ b/lib/phpunit/tests/phpunit_dataset_test.php
@@ -771,7 +771,7 @@ public function to_database_provider() {
      * @dataProvider to_database_provider
      * @covers ::to_database
      */
-    public function test_to_database(array $files, ?array $filter, ?string $exception, array $columns, array $rows) {
+    public function test_to_database(array $files, ?array $filter, ?string $exception, array $columns, array $rows): void {
         global $DB;
 
         $this->resetAfterTest();
diff --git a/lib/tests/authlib_test.php b/lib/tests/authlib_test.php
index 1e02010f7eda8..cb649428f1da7 100644
--- a/lib/tests/authlib_test.php
+++ b/lib/tests/authlib_test.php
@@ -448,7 +448,7 @@ public function test_user_loggedin_event_exceptions(): void {
     /**
      * Test the {@link signup_validate_data()} duplicate email validation.
      */
-    public function test_signup_validate_data_same_email() {
+    public function test_signup_validate_data_same_email(): void {
         global $CFG;
         require_once($CFG->libdir . '/authlib.php');
         require_once($CFG->libdir . '/phpmailer/moodle_phpmailer.php');
diff --git a/lib/tests/core_media_player_native_test.php b/lib/tests/core_media_player_native_test.php
index 6d563f47c20ab..5841c4bbbfecc 100644
--- a/lib/tests/core_media_player_native_test.php
+++ b/lib/tests/core_media_player_native_test.php
@@ -58,7 +58,7 @@ public function test_get_supported_extensions(): void {
     /**
      * Test method list_supported_urls
      */
-    public function test_list_supported_urls() {
+    public function test_list_supported_urls(): void {
         global $CFG;
         require_once($CFG->libdir . '/filelib.php');
         $nativeextensions = file_get_typegroup('extension', ['html_video', 'html_audio']);
diff --git a/lib/tests/curl_security_helper_test.php b/lib/tests/curl_security_helper_test.php
index 3d92e9f588b7a..568ff290d9fa8 100644
--- a/lib/tests/curl_security_helper_test.php
+++ b/lib/tests/curl_security_helper_test.php
@@ -37,7 +37,7 @@ class curl_security_helper_test extends \advanced_testcase {
      * @param bool $expected the expected result.
      * @dataProvider curl_security_url_data_provider
      */
-    public function test_curl_security_helper_url_is_blocked($dns, $url, $blockedhosts, $allowedports, $expected) {
+    public function test_curl_security_helper_url_is_blocked($dns, $url, $blockedhosts, $allowedports, $expected): void {
         $this->resetAfterTest(true);
         $helper = $this->getMockBuilder('\core\files\curl_security_helper')
             ->onlyMethods(['get_host_list_by_name'])
diff --git a/lib/tests/grouplib_test.php b/lib/tests/grouplib_test.php
index ac363b42cc2f1..b76bf7f9e38cb 100644
--- a/lib/tests/grouplib_test.php
+++ b/lib/tests/grouplib_test.php
@@ -2050,7 +2050,7 @@ public function test_get_all_groups_with_visibility(): void {
      *
      * @covers \groups_get_my_groups()
      */
-    public function test_get_my_groups_with_visibility() {
+    public function test_get_my_groups_with_visibility(): void {
         list($users, $groups) = $this->create_groups_with_visibilty();
 
         // Assign users to groups.
diff --git a/lib/tests/navigation/output/primary_test.php b/lib/tests/navigation/output/primary_test.php
index 54e042c2ae168..25507be006659 100644
--- a/lib/tests/navigation/output/primary_test.php
+++ b/lib/tests/navigation/output/primary_test.php
@@ -54,7 +54,7 @@ public function setUp(): void {
      *                             otherwise consider the user as non-logged in
      * @param array $expecteditems An array of nodes expected with content in them.
      */
-    public function test_primary_export(bool $withcustom, bool $withlang, string $userloggedin, array $expecteditems) {
+    public function test_primary_export(bool $withcustom, bool $withlang, string $userloggedin, array $expecteditems): void {
         global $PAGE, $CFG;
         if ($withcustom) {
             $CFG->custommenuitems = "Course search|/course/search.php
diff --git a/lib/tests/output/mustache_helper_collection_test.php b/lib/tests/output/mustache_helper_collection_test.php
index 049225e907c2e..296bd0185ae13 100644
--- a/lib/tests/output/mustache_helper_collection_test.php
+++ b/lib/tests/output/mustache_helper_collection_test.php
@@ -140,7 +140,7 @@ public function test_strip_disallowed_helpers($disallowed, $input, $expected): v
      * Any allowed helper should still be available to call during the
      * execution of a helper.
      */
-    public function test_disallowed_helpers_disabled_during_execution() {
+    public function test_disallowed_helpers_disabled_during_execution(): void {
         $engine = new \Mustache_Engine();
         $context = new \Mustache_Context();
         $lambdahelper = new \Mustache_LambdaHelper($engine, $context);
diff --git a/lib/tests/questionlib_test.php b/lib/tests/questionlib_test.php
index d4a7e07273f45..fa362c262211a 100644
--- a/lib/tests/questionlib_test.php
+++ b/lib/tests/questionlib_test.php
@@ -695,7 +695,7 @@ public function test_get_question_options_course_tags_in_course_question_context
      * get_question_options includes the tags and course tags for all questions in the list
      * if each question has course and question level tags.
      */
-    public function test_get_question_options_includes_question_and_course_tags() {
+    public function test_get_question_options_includes_question_and_course_tags(): void {
         list($category, $course, $quiz, $qcat, $questions) = $this->setup_quiz_and_questions('category');
         $question1 = $questions[0];
         $question2 = $questions[1];
diff --git a/lib/tests/task/database_logger_test.php b/lib/tests/task/database_logger_test.php
index 1a0261332d430..80588bf2fd294 100644
--- a/lib/tests/task/database_logger_test.php
+++ b/lib/tests/task/database_logger_test.php
@@ -212,7 +212,7 @@ public function test_store_log_for_task_adhoc_userid(): void {
      * @dataProvider    delete_task_logs_provider
      * @param   mixed   $ids
      */
-    public function test_delete_task_logs($ids) {
+    public function test_delete_task_logs($ids): void {
         $DB = $this->mock_database();
         $DB->expects($this->once())
             ->method('delete_records_list')
diff --git a/login/tests/login_lib_test.php b/login/tests/login_lib_test.php
index bdafdf7a1d967..2cab15a417404 100644
--- a/login/tests/login_lib_test.php
+++ b/login/tests/login_lib_test.php
@@ -383,7 +383,7 @@ public function test_core_login_validate_forgot_password_data($data, $errors = [
      *
      * Email addresses should be handled as case-insensitive but accent sensitive.
      */
-    public function test_core_login_process_password_reset_email_sensitivity() {
+    public function test_core_login_process_password_reset_email_sensitivity(): void {
         global $CFG;
         require_once($CFG->libdir.'/phpmailer/moodle_phpmailer.php');
 
diff --git a/media/player/html5audio/tests/player_test.php b/media/player/html5audio/tests/player_test.php
index da8bd00561528..2650ab06905d3 100644
--- a/media/player/html5audio/tests/player_test.php
+++ b/media/player/html5audio/tests/player_test.php
@@ -70,7 +70,7 @@ public function test_get_supported_extensions(): void {
     /**
      * Test method list_supported_urls()
      */
-    public function test_list_supported_urls() {
+    public function test_list_supported_urls(): void {
         global $CFG;
         require_once($CFG->libdir . '/filelib.php');
 
diff --git a/media/player/html5video/tests/player_test.php b/media/player/html5video/tests/player_test.php
index 66aaf731e5d0c..98ee415ca8424 100644
--- a/media/player/html5video/tests/player_test.php
+++ b/media/player/html5video/tests/player_test.php
@@ -67,7 +67,7 @@ public function test_get_supported_extensions(): void {
     /**
      * Test method list_supported_urls()
      */
-    public function test_list_supported_urls() {
+    public function test_list_supported_urls(): void {
         global $CFG;
         require_once($CFG->libdir . '/filelib.php');
 
diff --git a/message/tests/api_test.php b/message/tests/api_test.php
index cceae4fa6639b..b5801e8e492fd 100644
--- a/message/tests/api_test.php
+++ b/message/tests/api_test.php
@@ -1277,7 +1277,7 @@ public function test_get_conversations_message_format(): void {
     /**
      * Test verifying get_conversations identifies if a conversation is muted or not.
      */
-    public function test_get_conversations_some_muted() {
+    public function test_get_conversations_some_muted(): void {
         // Create some users.
         $user1 = self::getDataGenerator()->create_user();
         $user2 = self::getDataGenerator()->create_user();
@@ -5749,7 +5749,7 @@ public function test_get_conversation_counts(
         $expectedcounts,
         $expectedunreadcounts,
         $deletedusers
-    ) {
+    ): void {
         $generator = $this->getDataGenerator();
         $users = [
             $generator->create_user(),
@@ -5872,7 +5872,7 @@ public function test_get_unread_conversation_counts(
         $expectedcounts,
         $expectedunreadcounts,
         $deletedusers
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
         $users = [
diff --git a/message/tests/externallib_test.php b/message/tests/externallib_test.php
index a4b6f7f72fe3a..6769c630c8ac3 100644
--- a/message/tests/externallib_test.php
+++ b/message/tests/externallib_test.php
@@ -2032,7 +2032,7 @@ public function test_get_user_notification_preferences_permissions(): void {
      * If checks this by placing some users in the same course, where default caps would permit a user to view another user's
      * profile.
      */
-    public function test_message_search_users_messagingallusers_disabled() {
+    public function test_message_search_users_messagingallusers_disabled(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -2128,7 +2128,7 @@ public function test_message_search_users_messagingallusers_disabled() {
      * This test verifies that any contacts are returned, as well as any non-contacts, regardless of whether the searching user
      * can view their respective profile.
      */
-    public function test_message_search_users_messagingallusers_enabled() {
+    public function test_message_search_users_messagingallusers_enabled(): void {
         global $DB;
         $this->resetAfterTest();
 
@@ -4395,7 +4395,7 @@ public function test_get_conversations_user_in_group_and_individual_chat(): void
     /**
      * Test verifying get_conversations identifies if a conversation is muted or not.
      */
-    public function test_get_conversations_some_muted() {
+    public function test_get_conversations_some_muted(): void {
         $this->resetAfterTest();
 
         // Create some users.
@@ -5518,7 +5518,7 @@ public function test_get_conversation_counts(
         $expectedcounts,
         $expectedunreadcounts,
         $deletedusers
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
         $users = [
@@ -5615,7 +5615,7 @@ public function test_get_unread_conversation_counts(
         $expectedcounts,
         $expectedunreadcounts,
         $deletedusers
-    ) {
+    ): void {
         $this->resetAfterTest();
         $generator = $this->getDataGenerator();
         $users = [
diff --git a/message/tests/privacy/provider_test.php b/message/tests/privacy/provider_test.php
index f3f6c8f82fbc9..8f8cb4a6a7dae 100644
--- a/message/tests/privacy/provider_test.php
+++ b/message/tests/privacy/provider_test.php
@@ -1048,7 +1048,7 @@ public function test_delete_data_for_all_users_in_context(): void {
     /**
      * Test for provider::delete_data_for_user().
      */
-    public function test_delete_data_for_user() {
+    public function test_delete_data_for_user(): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -1382,7 +1382,7 @@ public function test_get_users_in_context_with_blocked_contact(): void {
     /**
      * Test for provider::delete_data_for_users().
      */
-    public function test_delete_data_for_users() {
+    public function test_delete_data_for_users(): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -1866,7 +1866,7 @@ public function test_export_conversations(): void {
     /**
      * Test for provider::delete_conversations_for_all_users().
      */
-    public function test_delete_conversations_for_all_users() {
+    public function test_delete_conversations_for_all_users(): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -2391,7 +2391,7 @@ public function test_delete_conversations_for_all_users_usercontext(): void {
     /**
      * Test for provider::delete_conversations_for_user().
      */
-    public function test_delete_conversations_for_user() {
+    public function test_delete_conversations_for_user(): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -2589,7 +2589,7 @@ public function test_delete_conversations_for_user() {
     /**
      * Test for provider::delete_conversations_for_users().
      */
-    public function test_delete_conversations_for_users() {
+    public function test_delete_conversations_for_users(): void {
         global $DB;
 
         $this->resetAfterTest();
diff --git a/mod/assign/tests/external/start_submission_test.php b/mod/assign/tests/external/start_submission_test.php
index 2394ceaf9fc6d..682d7d221631d 100644
--- a/mod/assign/tests/external/start_submission_test.php
+++ b/mod/assign/tests/external/start_submission_test.php
@@ -69,7 +69,7 @@ public function test_start_submission_when_user_has_no_capability_to_view_assign
     /**
      * Test start_submission if assignment cut off date has elapsed.
      */
-    public function test_start_submission_when_assignment_past_due_date() {
+    public function test_start_submission_when_assignment_past_due_date(): void {
         $fiveminago = time() - 300;
         list($assign, $instance, $student1, $student2, $teacher, $g1, $g2) = $this->create_submission_for_testing_status(
                 false, ['cutoffdate' => $fiveminago]);
@@ -87,7 +87,7 @@ public function test_start_submission_when_assignment_past_due_date() {
     /**
      * Test start_submission if time limit is disabled.
      */
-    public function test_start_submission_when_time_limit_disabled() {
+    public function test_start_submission_when_time_limit_disabled(): void {
         list($assign, $instance, $student1, $student2, $teacher, $g1, $g2) = $this->create_submission_for_testing_status();
         $result = start_submission::execute($instance->id);
         $filteredwarnings = array_filter($result['warnings'], function($warning) {
@@ -103,7 +103,7 @@ public function test_start_submission_when_time_limit_disabled() {
     /**
      * Test start_submission if time limit is not set for assignment.
      */
-    public function test_start_submission_when_time_limit_not_set() {
+    public function test_start_submission_when_time_limit_not_set(): void {
         set_config('enabletimelimit', '1', 'assign');
         list($assign, $instance, $student1, $student2, $teacher, $g1, $g2) = $this->create_submission_for_testing_status();
         $result = start_submission::execute($instance->id);
@@ -120,7 +120,7 @@ public function test_start_submission_when_time_limit_not_set() {
     /**
      * Test start_submission if user already has open submission.
      */
-    public function test_start_submission_when_submission_already_open() {
+    public function test_start_submission_when_submission_already_open(): void {
         global $DB;
         set_config('enabletimelimit', '1', 'assign');
         list($assign, $instance, $student1, $student2, $teacher, $g1, $g2) = $this->create_submission_for_testing_status(
@@ -142,7 +142,7 @@ public function test_start_submission_when_submission_already_open() {
     /**
      * Test start_submission if user has already submitted with no additional attempts available.
      */
-    public function test_start_submission_with_no_attempts_available() {
+    public function test_start_submission_with_no_attempts_available(): void {
         global $DB;
         set_config('enabletimelimit', '1', 'assign');
         list($assign, $instance, $student1, $student2, $teacher, $g1, $g2) = $this->create_submission_for_testing_status(
diff --git a/mod/assign/tests/externallib_test.php b/mod/assign/tests/externallib_test.php
index 7919f6bab418d..1e519aba23e20 100644
--- a/mod/assign/tests/externallib_test.php
+++ b/mod/assign/tests/externallib_test.php
@@ -332,7 +332,7 @@ public function test_get_assignments(): void {
     /**
      * Test get_assignments with submissionstatement.
      */
-    public function test_get_assignments_with_submissionstatement() {
+    public function test_get_assignments_with_submissionstatement(): void {
         global $DB, $USER, $CFG;
 
         $this->resetAfterTest(true);
diff --git a/mod/assign/tests/lib_test.php b/mod/assign/tests/lib_test.php
index 42ffbeca3eceb..a07412c540d4c 100644
--- a/mod/assign/tests/lib_test.php
+++ b/mod/assign/tests/lib_test.php
@@ -1377,7 +1377,7 @@ public function test_student_role_cant_update_due_event(): void {
      * able to update the assignment due date by changing the due date calendar
      * event.
      */
-    public function test_teacher_role_can_update_due_event() {
+    public function test_teacher_role_can_update_due_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . '/calendar/lib.php');
 
diff --git a/mod/bigbluebuttonbn/tests/external/get_recordings_test.php b/mod/bigbluebuttonbn/tests/external/get_recordings_test.php
index 556c894d3be09..ddda640e7cdf7 100644
--- a/mod/bigbluebuttonbn/tests/external/get_recordings_test.php
+++ b/mod/bigbluebuttonbn/tests/external/get_recordings_test.php
@@ -379,7 +379,7 @@ public function test_get_imported_recordings_only(): void {
      * @covers   \mod_bigbluebuttonbn\external\get_recordings::execute
      * @dataProvider recording_group_test_data
      */
-    public function test_get_recordings_groups($type, $groups, $users, $recordingsdata, $test, $coursemode) {
+    public function test_get_recordings_groups($type, $groups, $users, $recordingsdata, $test, $coursemode): void {
         $this->resetAfterTest();
         $dataset = compact('type', 'groups', 'users', 'recordingsdata', 'test', 'coursemode');
         $activityid = $this->create_from_dataset($dataset);
diff --git a/mod/bigbluebuttonbn/tests/lib_test.php b/mod/bigbluebuttonbn/tests/lib_test.php
index 166ee95bd1915..1fb00a50bd5cf 100644
--- a/mod/bigbluebuttonbn/tests/lib_test.php
+++ b/mod/bigbluebuttonbn/tests/lib_test.php
@@ -130,7 +130,7 @@ public function test_bigbluebuttonbn_delete_instance_with_running_meeting(): voi
      *
      * @covers ::bigbluebuttonbn_delete_instance
      */
-    public function test_bigbluebuttonbn_delete_instance_with_running_group_meetings() {
+    public function test_bigbluebuttonbn_delete_instance_with_running_group_meetings(): void {
         $this->resetAfterTest();
         $this->initialise_mock_server();
         $datagenerator = $this->getDataGenerator();
@@ -224,7 +224,7 @@ public function test_bigbluebuttonbn_user_complete(): void {
      *
      * @covers ::bigbluebuttonbn_get_recent_mod_activity
      */
-    public function test_bigbluebuttonbn_get_recent_mod_activity() {
+    public function test_bigbluebuttonbn_get_recent_mod_activity(): void {
         $this->initialise_mock_server();
         $this->resetAfterTest();
 
diff --git a/mod/bigbluebuttonbn/tests/local/proxy/recording_proxy_test.php b/mod/bigbluebuttonbn/tests/local/proxy/recording_proxy_test.php
index e50dd4a1c0ecc..829597a91465c 100644
--- a/mod/bigbluebuttonbn/tests/local/proxy/recording_proxy_test.php
+++ b/mod/bigbluebuttonbn/tests/local/proxy/recording_proxy_test.php
@@ -37,7 +37,7 @@ class recording_proxy_test extends \advanced_testcase {
      *
      * @return void
      */
-    public function test_fetch_recordings() {
+    public function test_fetch_recordings(): void {
         $this->resetAfterTest();
         $this->initialise_mock_server();
         [$context, $cm, $bbbactivity] = $this->create_instance();
@@ -55,7 +55,7 @@ public function test_fetch_recordings() {
      *
      * @return void
      */
-    public function test_fetch_recordings_breakoutroom() {
+    public function test_fetch_recordings_breakoutroom(): void {
         $this->resetAfterTest();
         $this->initialise_mock_server();
         [$context, $cm, $bbbactivity] = $this->create_instance();
diff --git a/mod/bigbluebuttonbn/tests/output/recording_row_playback_test.php b/mod/bigbluebuttonbn/tests/output/recording_row_playback_test.php
index 510a789c60472..2c859d778ec78 100644
--- a/mod/bigbluebuttonbn/tests/output/recording_row_playback_test.php
+++ b/mod/bigbluebuttonbn/tests/output/recording_row_playback_test.php
@@ -95,7 +95,7 @@ public function setUp(): void {
      * @covers       \recording_row_playback::should_be_included
      * @dataProvider should_be_included_data_provider
      */
-    public function test_should_be_included(string $role, array $canview, object $globalsettings = null) {
+    public function test_should_be_included(string $role, array $canview, object $globalsettings = null): void {
         global $PAGE;
         $this->resetAfterTest();
         ['recordings' => $recordingsdata, 'activity' => $activity] = $this->create_activity_with_recordings(
diff --git a/mod/choice/tests/lib_test.php b/mod/choice/tests/lib_test.php
index a5a7108db7ac3..9cd5eecf49f46 100644
--- a/mod/choice/tests/lib_test.php
+++ b/mod/choice/tests/lib_test.php
@@ -889,7 +889,7 @@ public function test_mod_choice_core_calendar_event_timestart_updated_unknown_ev
      * A CHOICE_EVENT_TYPE_OPEN event should update the timeopen property of
      * the choice activity.
      */
-    public function test_mod_choice_core_calendar_event_timestart_updated_open_event() {
+    public function test_mod_choice_core_calendar_event_timestart_updated_open_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
@@ -950,7 +950,7 @@ public function test_mod_choice_core_calendar_event_timestart_updated_open_event
      * A CHOICE_EVENT_TYPE_CLOSE event should update the timeclose property of
      * the choice activity.
      */
-    public function test_mod_choice_core_calendar_event_timestart_updated_close_event() {
+    public function test_mod_choice_core_calendar_event_timestart_updated_close_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
diff --git a/mod/data/tests/lib_test.php b/mod/data/tests/lib_test.php
index 1e4c7a45ff104..15b1942899722 100644
--- a/mod/data/tests/lib_test.php
+++ b/mod/data/tests/lib_test.php
@@ -1706,7 +1706,7 @@ public function test_mod_data_core_calendar_event_timestart_updated_unknown_even
     /**
      * A DATA_EVENT_TYPE_OPEN event should update the timeavailablefrom property of the data activity.
      */
-    public function test_mod_data_core_calendar_event_timestart_updated_open_event() {
+    public function test_mod_data_core_calendar_event_timestart_updated_open_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
@@ -1763,7 +1763,7 @@ public function test_mod_data_core_calendar_event_timestart_updated_open_event()
     /**
      * A DATA_EVENT_TYPE_CLOSE event should update the timeavailableto property of the data activity.
      */
-    public function test_mod_data_core_calendar_event_timestart_updated_close_event() {
+    public function test_mod_data_core_calendar_event_timestart_updated_close_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
diff --git a/mod/data/tests/manager_test.php b/mod/data/tests/manager_test.php
index 65d829a1109a4..3fae83e2d86ed 100644
--- a/mod/data/tests/manager_test.php
+++ b/mod/data/tests/manager_test.php
@@ -222,7 +222,7 @@ public function test_has_fields(): void {
      *
      * @covers ::get_available_presets
      */
-    public function test_get_available_presets() {
+    public function test_get_available_presets(): void {
         global $DB;
 
         $this->resetAfterTest();
@@ -323,7 +323,7 @@ public function test_get_available_presets() {
      *
      * @covers ::get_available_plugin_presets
      */
-    public function test_get_available_plugin_presets() {
+    public function test_get_available_plugin_presets(): void {
         $this->resetAfterTest();
         $this->setAdminUser();
 
@@ -369,7 +369,7 @@ public function test_get_available_plugin_presets() {
      *
      * @covers ::get_available_saved_presets
      */
-    public function test_get_available_saved_presets() {
+    public function test_get_available_saved_presets(): void {
         global $DB;
 
         $this->resetAfterTest();
diff --git a/mod/data/tests/preset_test.php b/mod/data/tests/preset_test.php
index 4df4c3b38febe..163bfd09545ae 100644
--- a/mod/data/tests/preset_test.php
+++ b/mod/data/tests/preset_test.php
@@ -208,7 +208,7 @@ public function test_create_from_fullname(): void {
      *
      * @covers ::save
      */
-    public function test_save_new_preset() {
+    public function test_save_new_preset(): void {
         $this->resetAfterTest();
         $this->setAdminUser();
 
diff --git a/mod/feedback/tests/lib_test.php b/mod/feedback/tests/lib_test.php
index ebddb43138c9a..0656b3fc2f1b6 100644
--- a/mod/feedback/tests/lib_test.php
+++ b/mod/feedback/tests/lib_test.php
@@ -1076,7 +1076,7 @@ public function test_student_role_cant_update_time_close_event(): void {
      * The activity should update if a teacher modifies the calendar
      * event.
      */
-    public function test_teacher_role_can_update_time_close_event() {
+    public function test_teacher_role_can_update_time_close_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . '/calendar/lib.php');
 
diff --git a/mod/forum/tests/builders_exported_posts_test.php b/mod/forum/tests/builders_exported_posts_test.php
index c8822db5fd573..fd88c64363a4c 100644
--- a/mod/forum/tests/builders_exported_posts_test.php
+++ b/mod/forum/tests/builders_exported_posts_test.php
@@ -142,7 +142,7 @@ public function test_build_throws_exception_on_missing_discussions(): void {
      * Test the build function returns the exported posts in the order that the posts are
      * given.
      */
-    public function test_build_returns_posts_in_order() {
+    public function test_build_returns_posts_in_order(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
@@ -185,7 +185,7 @@ public function test_build_returns_posts_in_order() {
     /**
      * Test the build function loads authors.
      */
-    public function test_build_loads_authors() {
+    public function test_build_loads_authors(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
@@ -230,7 +230,7 @@ public function test_build_loads_authors() {
     /**
      * Test the build function loads attachments.
      */
-    public function test_build_loads_attachments() {
+    public function test_build_loads_attachments(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
@@ -306,7 +306,7 @@ public function test_build_loads_attachments() {
     /**
      * Test the build function loads author groups.
      */
-    public function test_build_loads_author_groups() {
+    public function test_build_loads_author_groups(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
@@ -376,7 +376,7 @@ public function test_build_loads_author_groups() {
     /**
      * Test the build function loads tags.
      */
-    public function test_build_loads_tags() {
+    public function test_build_loads_tags(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
@@ -437,7 +437,7 @@ public function test_build_loads_tags() {
     /**
      * Test the build function loads read_receipts.
      */
-    public function test_build_loads_read_receipts() {
+    public function test_build_loads_read_receipts(): void {
         $this->resetAfterTest();
 
         $datagenerator = $this->getDataGenerator();
diff --git a/mod/forum/tests/entities_sorter_test.php b/mod/forum/tests/entities_sorter_test.php
index 28e32e285a609..62b4697fcf288 100644
--- a/mod/forum/tests/entities_sorter_test.php
+++ b/mod/forum/tests/entities_sorter_test.php
@@ -29,7 +29,7 @@ class entities_sorter_test extends \advanced_testcase {
     /**
      * Test the entity returns expected values.
      */
-    public function test_entity_sort_into_children() {
+    public function test_entity_sort_into_children(): void {
         $this->resetAfterTest();
         $sorter = new sorter_entity(
             function($entity) {
@@ -59,7 +59,7 @@ function($entity) {
     /**
      * Test the entity returns expected values.
      */
-    public function test_entity_flatten_children() {
+    public function test_entity_flatten_children(): void {
         $this->resetAfterTest();
         $sorter = new sorter_entity(
             function($entity) {
diff --git a/mod/forum/tests/privacy/provider_test.php b/mod/forum/tests/privacy/provider_test.php
index 0e47f7fefd66b..11f18124b65cb 100644
--- a/mod/forum/tests/privacy/provider_test.php
+++ b/mod/forum/tests/privacy/provider_test.php
@@ -1063,7 +1063,7 @@ public function test_post_tags(): void {
     /**
      * Ensure that all user data is deleted from a context.
      */
-    public function test_all_users_deleted_from_context() {
+    public function test_all_users_deleted_from_context(): void {
         global $DB;
 
         $fs = get_file_storage();
@@ -1268,7 +1268,7 @@ public function test_all_users_deleted_from_context() {
     /**
      * Ensure that all user data is deleted for a specific context.
      */
-    public function test_delete_data_for_user() {
+    public function test_delete_data_for_user(): void {
         global $DB;
 
         $fs = get_file_storage();
@@ -1483,7 +1483,7 @@ public function test_delete_data_for_user() {
     /**
      * Ensure that user data for specific users is deleted from a specified context.
      */
-    public function test_delete_data_for_users() {
+    public function test_delete_data_for_users(): void {
         global $DB;
 
         $fs = get_file_storage();
diff --git a/mod/forum/tests/vaults_forum_test.php b/mod/forum/tests/vaults_forum_test.php
index 71b1210fccd88..e240764f6e63d 100644
--- a/mod/forum/tests/vaults_forum_test.php
+++ b/mod/forum/tests/vaults_forum_test.php
@@ -85,7 +85,7 @@ public function test_get_from_course_module_id(): void {
      *
      * @covers ::get_from_course_module_ids
      */
-    public function test_get_from_course_module_ids() {
+    public function test_get_from_course_module_ids(): void {
         $this->resetAfterTest();
 
         $vaultfactory = \mod_forum\local\container::get_vault_factory();
diff --git a/mod/h5pactivity/tests/external/get_h5pactivities_by_courses_test.php b/mod/h5pactivity/tests/external/get_h5pactivities_by_courses_test.php
index 17e80c82bfc72..33908fccfa5f3 100644
--- a/mod/h5pactivity/tests/external/get_h5pactivities_by_courses_test.php
+++ b/mod/h5pactivity/tests/external/get_h5pactivities_by_courses_test.php
@@ -48,7 +48,7 @@ class get_h5pactivities_by_courses_test extends externallib_advanced_testcase {
     /**
      * Test test_get_h5pactivities_by_courses user student.
      */
-    public function test_get_h5pactivities_by_courses() {
+    public function test_get_h5pactivities_by_courses(): void {
         global $CFG, $DB;
 
         $this->resetAfterTest();
diff --git a/mod/lesson/tests/lib_test.php b/mod/lesson/tests/lib_test.php
index 17a2e63ea76b2..0f6e6406fc6d7 100644
--- a/mod/lesson/tests/lib_test.php
+++ b/mod/lesson/tests/lib_test.php
@@ -827,7 +827,7 @@ public function test_mod_lesson_core_calendar_event_timestart_updated_unknown_ev
     /**
      * A LESSON_EVENT_TYPE_OPEN event should update the available property of the lesson activity.
      */
-    public function test_mod_lesson_core_calendar_event_timestart_updated_open_event() {
+    public function test_mod_lesson_core_calendar_event_timestart_updated_open_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
@@ -887,7 +887,7 @@ public function test_mod_lesson_core_calendar_event_timestart_updated_open_event
     /**
      * A LESSON_EVENT_TYPE_CLOSE event should update the deadline property of the lesson activity.
      */
-    public function test_mod_lesson_core_calendar_event_timestart_updated_close_event() {
+    public function test_mod_lesson_core_calendar_event_timestart_updated_close_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
         $this->resetAfterTest(true);
diff --git a/mod/quiz/tests/calendar_event_modified_test.php b/mod/quiz/tests/calendar_event_modified_test.php
index 5e52b27743506..6caf143da6b3a 100644
--- a/mod/quiz/tests/calendar_event_modified_test.php
+++ b/mod/quiz/tests/calendar_event_modified_test.php
@@ -273,7 +273,7 @@ public function test_student_role_cant_update_quiz_activity(): void {
      * able to update the quiz activity dates by changing the calendar
      * event.
      */
-    public function test_teacher_role_can_update_quiz_activity() {
+    public function test_teacher_role_can_update_quiz_activity(): void {
         global $DB;
 
         $this->resetAfterTest();
diff --git a/mod/quiz/tests/local_structure_slot_random_test.php b/mod/quiz/tests/local_structure_slot_random_test.php
index 039f159cea99b..dd2a764ad4f6c 100644
--- a/mod/quiz/tests/local_structure_slot_random_test.php
+++ b/mod/quiz/tests/local_structure_slot_random_test.php
@@ -226,7 +226,7 @@ public function test_set_tags_filter(): void {
             (array)json_decode($tagspropery)->filters->qtagids->values);
     }
 
-    public function test_insert() {
+    public function test_insert(): void {
         global $SITE;
 
         $this->resetAfterTest();
diff --git a/mod/scorm/tests/externallib_test.php b/mod/scorm/tests/externallib_test.php
index c365adfdea545..3f7fbc5fa0aa1 100644
--- a/mod/scorm/tests/externallib_test.php
+++ b/mod/scorm/tests/externallib_test.php
@@ -227,7 +227,7 @@ public function test_mod_scorm_get_scorm_attempt_count_invalid_userid(): void {
     /**
      * Test get scorm scoes
      */
-    public function test_mod_scorm_get_scorm_scoes() {
+    public function test_mod_scorm_get_scorm_scoes(): void {
         global $DB;
 
         $this->resetAfterTest(true);
diff --git a/mod/scorm/tests/lib_test.php b/mod/scorm/tests/lib_test.php
index 8d85bad93d45e..01fb3cd6d5ab0 100644
--- a/mod/scorm/tests/lib_test.php
+++ b/mod/scorm/tests/lib_test.php
@@ -633,7 +633,7 @@ public function test_mod_scorm_core_calendar_event_timestart_updated_unknown_eve
      * A SCORM_EVENT_TYPE_OPEN event should update the timeopen property of
      * the scorm activity.
      */
-    public function test_mod_scorm_core_calendar_event_timestart_updated_open_event() {
+    public function test_mod_scorm_core_calendar_event_timestart_updated_open_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
@@ -694,7 +694,7 @@ public function test_mod_scorm_core_calendar_event_timestart_updated_open_event(
      * A SCORM_EVENT_TYPE_CLOSE event should update the timeclose property of
      * the scorm activity.
      */
-    public function test_mod_scorm_core_calendar_event_timestart_updated_close_event() {
+    public function test_mod_scorm_core_calendar_event_timestart_updated_close_event(): void {
         global $CFG, $DB;
         require_once($CFG->dirroot . "/calendar/lib.php");
 
diff --git a/mod/wiki/tests/privacy/provider_test.php b/mod/wiki/tests/privacy/provider_test.php
index e39ef8d3feb59..2a442027468ff 100644
--- a/mod/wiki/tests/privacy/provider_test.php
+++ b/mod/wiki/tests/privacy/provider_test.php
@@ -327,7 +327,7 @@ public function test_get_users_in_context(): void {
     /**
      * Export data for user 1
      */
-    public function test_export_user_data1() {
+    public function test_export_user_data1(): void {
 
         // Export all contexts for the first user.
         $contextids = array_values(array_map(function($c) {
@@ -383,7 +383,7 @@ public function test_export_user_data1() {
     /**
      * Test export data for user 2
      */
-    public function test_export_user_data2() {
+    public function test_export_user_data2(): void {
 
         // Export all contexts for the second user.
         $contextids = array_values(array_map(function($c) {
@@ -434,7 +434,7 @@ public function test_export_user_data2() {
     /**
      * Test export data for user 3 (locks, empty individual wiki)
      */
-    public function test_export_user_data3() {
+    public function test_export_user_data3(): void {
 
         // Export all contexts for the third user.
         $contextids = array_values(array_map(function($c) {
@@ -515,7 +515,7 @@ protected function add_comment($page, $text) {
     /**
      * Test export data when there are comments.
      */
-    public function test_export_user_data_with_comments() {
+    public function test_export_user_data_with_comments(): void {
         global $DB;
         // Comment on each page in the first wiki as the first user.
         $this->setUser($this->users[1]);
diff --git a/privacy/tests/moodle_content_writer_test.php b/privacy/tests/moodle_content_writer_test.php
index 7b281a9ded7d6..d718f70ca6cd2 100644
--- a/privacy/tests/moodle_content_writer_test.php
+++ b/privacy/tests/moodle_content_writer_test.php
@@ -705,7 +705,7 @@ public function test_export_user_preference_context_block($component, $key, $val
      *
      * @covers ::export_user_preference
      */
-    public function test_export_user_preference_context_block_multiple_instances() {
+    public function test_export_user_preference_context_block_multiple_instances(): void {
         $this->resetAfterTest();
 
         $generator = $this->getDataGenerator();
@@ -1323,7 +1323,7 @@ public function rewrite_pluginfile_urls_provider() {
         ];
     }
 
-    public function test_export_html_functions() {
+    public function test_export_html_functions(): void {
         $this->resetAfterTest();
 
         $data = (object) ['key' => 'value'];
diff --git a/question/tests/externallib_test.php b/question/tests/externallib_test.php
index 002c87342713e..f475cdd8dc46b 100644
--- a/question/tests/externallib_test.php
+++ b/question/tests/externallib_test.php
@@ -195,7 +195,7 @@ public function test_get_random_question_summaries_variations(
         $includesubcategories,
         $usetagnames,
         $expectedquestionindexes
-    ) {
+    ): void {
         $this->resetAfterTest();
 
         $context = \context_system::instance();
@@ -365,7 +365,7 @@ public function test_get_random_question_summaries_formats_returned_questions():
     /**
      * get_random_question_summaries should allow limiting and offsetting of the result set.
      */
-    public function test_get_random_question_summaries_with_limit_and_offset() {
+    public function test_get_random_question_summaries_with_limit_and_offset(): void {
         $this->resetAfterTest();
         $numberofquestions = 5;
         $includesubcategories = false;
diff --git a/question/type/calculated/tests/question_type_test.php b/question/type/calculated/tests/question_type_test.php
index 271c60792b143..f638bcdb29e43 100644
--- a/question/type/calculated/tests/question_type_test.php
+++ b/question/type/calculated/tests/question_type_test.php
@@ -64,7 +64,7 @@ public function test_get_random_guess_score(): void {
         $this->assertEquals(0.1, $this->qtype->get_random_guess_score($q));
     }
 
-    public function test_load_question() {
+    public function test_load_question(): void {
         $this->resetAfterTest();
 
         $syscontext = \context_system::instance();
diff --git a/question/type/multianswer/tests/question_type_test.php b/question/type/multianswer/tests/question_type_test.php
index 34485048c64b3..6cc5a6aba2e51 100644
--- a/question/type/multianswer/tests/question_type_test.php
+++ b/question/type/multianswer/tests/question_type_test.php
@@ -148,7 +148,7 @@ public function test_get_random_guess_score_with_all_missing_subquestions(): voi
         $this->assertNull($this->qtype->get_random_guess_score($questiondata));
     }
 
-    public function test_load_question() {
+    public function test_load_question(): void {
         $this->resetAfterTest();
 
         $syscontext = \context_system::instance();
diff --git a/repository/contentbank/tests/search/search_test.php b/repository/contentbank/tests/search/search_test.php
index 1ea14b9037f47..d2896bc2b1555 100644
--- a/repository/contentbank/tests/search/search_test.php
+++ b/repository/contentbank/tests/search/search_test.php
@@ -47,7 +47,7 @@ class search_test extends \advanced_testcase {
      * @param string $search The search string
      * @param array $expected The array containing the expected content names that should be returned by the search
      */
-    public function test_get_search_contents(array $contentnames, string $search, array $expected) {
+    public function test_get_search_contents(array $contentnames, string $search, array $expected): void {
         $this->resetAfterTest();
 
         $admin = get_admin();
diff --git a/repository/dropbox/tests/api_test.php b/repository/dropbox/tests/api_test.php
index ea4360068785a..6aec039ce13b5 100644
--- a/repository/dropbox/tests/api_test.php
+++ b/repository/dropbox/tests/api_test.php
@@ -339,7 +339,7 @@ public function test_fetch_dropbox_data_endpoint(): void {
     /**
      * Some Dropbox endpoints require that the POSTFIELDS be set to null exactly.
      */
-    public function test_fetch_dropbox_data_postfields_null() {
+    public function test_fetch_dropbox_data_postfields_null(): void {
         $mock = $this->getMockBuilder(\repository_dropbox\dropbox::class)
             ->disableOriginalConstructor()
             ->onlyMethods([
@@ -365,7 +365,7 @@ public function test_fetch_dropbox_data_postfields_null() {
     /**
      * When data is specified, it should be json_encoded in POSTFIELDS.
      */
-    public function test_fetch_dropbox_data_postfields_data() {
+    public function test_fetch_dropbox_data_postfields_data(): void {
         $mock = $this->getMockBuilder(\repository_dropbox\dropbox::class)
             ->disableOriginalConstructor()
             ->onlyMethods([
@@ -442,7 +442,7 @@ public function test_fetch_dropbox_data_recurse_on_additional_records(): void {
     /**
      * Base tests for the fetch_dropbox_content function.
      */
-    public function test_fetch_dropbox_content() {
+    public function test_fetch_dropbox_content(): void {
         $mock = $this->getMockBuilder(\repository_dropbox\dropbox::class)
             ->disableOriginalConstructor()
             ->onlyMethods([
diff --git a/tag/tests/privacy/provider_test.php b/tag/tests/privacy/provider_test.php
index 5394d27b940c2..a07b1bb560652 100644
--- a/tag/tests/privacy/provider_test.php
+++ b/tag/tests/privacy/provider_test.php
@@ -250,7 +250,7 @@ public function test_delete_data_for_all_users_in_context(): void {
         $this->assertEquals(0, $DB->count_records('tag_instance', []));
     }
 
-    public function test_export_data_for_user() {
+    public function test_export_data_for_user(): void {
         global $DB;
         list($user1, $user2) = $this->set_up_tags();
         $context = \context_system::instance();
diff --git a/tag/tests/taglib_test.php b/tag/tests/taglib_test.php
index 7a973515e7c95..96206f69bf452 100644
--- a/tag/tests/taglib_test.php
+++ b/tag/tests/taglib_test.php
@@ -325,7 +325,7 @@ protected function prepare_correlated() {
     /**
      * Test for function compute_correlations() that is part of tag cron
      */
-    public function test_correlations() {
+    public function test_correlations(): void {
         global $DB;
         $task = new \core\task\tag_cron_task();
 
@@ -929,7 +929,7 @@ public function test_combine_tags(): void {
     /**
      * Testing function core_tag_tag::combine_tags() when related tags are present.
      */
-    public function test_combine_tags_with_related() {
+    public function test_combine_tags_with_related(): void {
         $collid = core_tag_collection::get_default();
         $context = \context_system::instance();
         core_tag_tag::set_item_tags('core', 'course', 10, $context, array('Cat', 'Cats', 'Dog'));
@@ -1014,7 +1014,7 @@ public function test_get_tags_by_area_in_contexts_empty(): void {
      * have instances in the given context even when there is only a single
      * instance.
      */
-    public function test_get_tags_by_area_in_contexts_single_tag_one_context() {
+    public function test_get_tags_by_area_in_contexts_single_tag_one_context(): void {
         $tagnames = ['foo'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1043,7 +1043,7 @@ public function test_get_tags_by_area_in_contexts_single_tag_one_context() {
      * that have tag instances in for the area in the given context and
      * should ignore all tags that don't have an instance.
      */
-    public function test_get_tags_by_area_in_contexts_multiple_tags_one_context() {
+    public function test_get_tags_by_area_in_contexts_multiple_tags_one_context(): void {
         $tagnames = ['foo', 'bar', 'baz'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1073,7 +1073,7 @@ public function test_get_tags_by_area_in_contexts_multiple_tags_one_context() {
      * Tags with tag instances in the same area with in difference contexts
      * should be ignored.
      */
-    public function test_get_tags_by_area_in_contexts_multiple_tags_multiple_contexts() {
+    public function test_get_tags_by_area_in_contexts_multiple_tags_multiple_contexts(): void {
         $tagnames = ['foo', 'bar', 'baz', 'bop', 'bam', 'bip'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1191,7 +1191,7 @@ public function test_get_items_tags_unknown_component_itemtype(): void {
      *      3 => []
      * ]
      */
-    public function test_get_items_tags_missing_itemids() {
+    public function test_get_items_tags_missing_itemids(): void {
         $user1 = $this->getDataGenerator()->create_user();
         $user2 = $this->getDataGenerator()->create_user();
         $user3 = $this->getDataGenerator()->create_user();
@@ -1232,7 +1232,7 @@ public function test_get_items_tags_missing_itemids() {
      * set_item_tags should remove any tags that aren't in the given list and should
      * add any instances that are missing.
      */
-    public function test_set_item_tags_no_multiple_context_add_remove_instances() {
+    public function test_set_item_tags_no_multiple_context_add_remove_instances(): void {
         $tagnames = ['foo', 'bar', 'baz', 'bop'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1312,7 +1312,7 @@ public function test_set_item_tags_no_multiple_context_updates_context_of_instan
      * the new set of tags, regardless of the context that the tag instance
      * is in.
      */
-    public function test_set_item_tags_no_multiple_contex_deletes_old_instancest() {
+    public function test_set_item_tags_no_multiple_contex_deletes_old_instancest(): void {
         $tagnames = ['foo', 'bar', 'baz', 'bop'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1361,7 +1361,7 @@ public function test_set_item_tags_no_multiple_contex_deletes_old_instancest() {
      * set_item_tags should not change tag instances in a different context to the one
      * it's opertating on if the tag area allows instances from multiple contexts.
      */
-    public function test_set_item_tags_allow_multiple_context_doesnt_update_context() {
+    public function test_set_item_tags_allow_multiple_context_doesnt_update_context(): void {
         global $DB;
         $tagnames = ['foo', 'bar', 'bop'];
         $collid = core_tag_collection::get_default();
@@ -1414,7 +1414,7 @@ public function test_set_item_tags_allow_multiple_context_doesnt_update_context(
      * the new set of tags only in the same context if the tag area allows
      * multiple contexts.
      */
-    public function test_set_item_tags_allow_multiple_context_deletes_instances_in_same_context() {
+    public function test_set_item_tags_allow_multiple_context_deletes_instances_in_same_context(): void {
         $tagnames = ['foo', 'bar', 'baz', 'bop'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1458,7 +1458,7 @@ public function test_set_item_tags_allow_multiple_context_deletes_instances_in_s
      * set_item_tags should allow multiple instances of the same tag in different
      * contexts if the tag area allows multiple contexts.
      */
-    public function test_set_item_tags_allow_multiple_context_same_tag_multiple_contexts() {
+    public function test_set_item_tags_allow_multiple_context_same_tag_multiple_contexts(): void {
         $tagnames = ['foo'];
         $collid = core_tag_collection::get_default();
         $tags = core_tag_tag::create_if_missing($collid, $tagnames);
@@ -1788,7 +1788,7 @@ public function test_delete_instances_with_component_and_context(): void {
      * delete_instances should delete all tag instances for a component, item type
      * and context if given the component, itemtype, and context id as parameters.
      */
-    public function test_delete_instances_with_component_and_itemtype_and_context() {
+    public function test_delete_instances_with_component_and_itemtype_and_context(): void {
         global $DB;
 
         $tagnames = ['foo', 'bar', 'baz'];
diff --git a/user/tests/userlib_test.php b/user/tests/userlib_test.php
index bdb44dc87d394..9f5183717fdee 100644
--- a/user/tests/userlib_test.php
+++ b/user/tests/userlib_test.php
@@ -984,7 +984,7 @@ public function test_user_get_user_details_permissions(): void {
      * Test user_get_user_details_groups.
      * @covers ::user_get_user_details
      */
-    public function test_user_get_user_details_groups() {
+    public function test_user_get_user_details_groups(): void {
         $this->resetAfterTest();
 
         // Create user and modify user profile.