diff --git a/admin/classes/table/hook_list_table.php b/admin/classes/table/hook_list_table.php
index 1ffc092708b..7f14bb73a83 100644
--- a/admin/classes/table/hook_list_table.php
+++ b/admin/classes/table/hook_list_table.php
@@ -91,7 +91,7 @@ class hook_list_table extends flexible_table {
      */
     public function out(): void {
         // All hook consumers referenced from the db/hooks.php files.
-        $hookmanager = \core\hook\manager::get_instance();
+        $hookmanager = \core\di::get(\core\hook\manager::class);
         $allhooks = (array)$hookmanager->get_all_callbacks();
 
         // Add any unused hooks.
diff --git a/admin/hooks.php b/admin/hooks.php
index e132b65525d..9cca9da9570 100644
--- a/admin/hooks.php
+++ b/admin/hooks.php
@@ -30,7 +30,7 @@ require_once($CFG->libdir . '/tablelib.php');
 admin_externalpage_setup('hooksoverview');
 require_capability('moodle/site:config', \core\context\system::instance());
 
-$hookmanager = \core\hook\manager::get_instance();
+$hookmanager = \core\di::get(\core\hook\manager::class);
 
 echo $OUTPUT->header();
 echo $OUTPUT->heading(get_string('hooksoverview', 'core_admin'));
diff --git a/admin/tool/mfa/classes/manager.php b/admin/tool/mfa/classes/manager.php
index c9a0454dda5..d8d093c44f1 100644
--- a/admin/tool/mfa/classes/manager.php
+++ b/admin/tool/mfa/classes/manager.php
@@ -334,7 +334,7 @@ class manager {
 
             // Allow plugins to callback as soon possible after user has passed MFA.
             $hook = new \tool_mfa\hook\after_user_passed_mfa();
-            \core\hook\manager::get_instance()->dispatch($hook);
+            \core\di::get(\core\hook\manager::class)->dispatch($hook);
 
             // Add/update record in DB for users last mfa auth.
             self::update_pass_time();
diff --git a/admin/user/user_bulk_forms.php b/admin/user/user_bulk_forms.php
index 0b36c941d15..1a1604e225a 100644
--- a/admin/user/user_bulk_forms.php
+++ b/admin/user/user_bulk_forms.php
@@ -130,7 +130,7 @@ class user_bulk_action_form extends moodleform {
         }
 
         // Any plugin can append user bulk actions to this list by implementing a hook callback.
-        \core\hook\manager::get_instance()->dispatch($hook);
+        \core\di::get(\core\hook\manager::class)->dispatch($hook);
 
         // This method may be called from 'Bulk actions' and 'Browse user list' pages. Some actions
         // may be irrelevant in one of the contexts and they can be excluded by specifying the
diff --git a/backup/util/helper/backup_cron_helper.class.php b/backup/util/helper/backup_cron_helper.class.php
index 2674f5d00c6..ecd1617fa7e 100644
--- a/backup/util/helper/backup_cron_helper.class.php
+++ b/backup/util/helper/backup_cron_helper.class.php
@@ -797,7 +797,7 @@ abstract class backup_cron_automated_helper {
 
         // Exclude events defined by hook.
         $hook = new \core_backup\hook\before_course_modified_check();
-        \core\hook\manager::get_instance()->dispatch($hook);
+        \core\di::get(\core\hook\manager::class)->dispatch($hook);
 
         foreach ($readers as $readerpluginname => $reader) {
             $params = [
diff --git a/course/edit_form.php b/course/edit_form.php
index 5a60a5604f4..2e60b3a9ab9 100644
--- a/course/edit_form.php
+++ b/course/edit_form.php
@@ -1,5 +1,10 @@
 <?php
 
+use core\{
+    di,
+    hook,
+};
+
 defined('MOODLE_INTERNAL') || die;
 
 require_once($CFG->libdir.'/formslib.php');
@@ -419,7 +424,7 @@ class course_edit_form extends moodleform {
         $handler->instance_form_definition($mform, empty($course->id) ? 0 : $course->id);
 
         $hook = new \core_course\hook\after_form_definition($this, $mform);
-        \core\hook\manager::get_instance()->dispatch($hook);
+        di::get(hook\manager::class)->dispatch($hook);
 
         // When two elements we need a group.
         $buttonarray = array();
@@ -502,7 +507,7 @@ class course_edit_form extends moodleform {
         $handler->instance_form_definition_after_data($mform, empty($courseid) ? 0 : $courseid);
 
         $hook = new \core_course\hook\after_form_definition_after_data($this, $mform);
-        \core\hook\manager::get_instance()->dispatch($hook);
+        di::get(hook\manager::class)->dispatch($hook);
     }
 
     /**
@@ -550,7 +555,7 @@ class course_edit_form extends moodleform {
         $errors  = array_merge($errors, $handler->instance_form_validation($data, $files));
 
         $hook = new \core_course\hook\after_form_validation($this, $data, $files);
-        \core\hook\manager::get_instance()->dispatch($hook);
+        di::get(hook\manager::class)->dispatch($hook);
         $pluginerrors = $hook->get_errors();
         if (!empty($pluginerrors)) {
             $errors = array_merge($errors, $pluginerrors);
diff --git a/course/format/classes/local/cmactions.php b/course/format/classes/local/cmactions.php
index 347b2a31a5e..3e9f1e54c69 100644
--- a/course/format/classes/local/cmactions.php
+++ b/course/format/classes/local/cmactions.php
@@ -72,8 +72,9 @@ class cmactions extends baseactions {
 
         // Modules may add some logic to renaming.
         $modinfo = get_fast_modinfo($cm->course);
-        $hook = new \core_courseformat\hook\after_cm_name_edited($modinfo->get_cm($cm->id), $name);
-        \core\hook\manager::get_instance()->dispatch($hook);
+        \core\di::get(\core\hook\manager::class)->dispatch(
+            new \core_courseformat\hook\after_cm_name_edited($modinfo->get_cm($cm->id), $name),
+        );
 
         // Attempt to update the grade item if relevant.
         $grademodule = $DB->get_record($cm->modname, ['id' => $cm->instance]);
diff --git a/course/lib.php b/course/lib.php
index 0d43762d618..a4a5a4da1ba 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -24,6 +24,10 @@
 
 defined('MOODLE_INTERNAL') || die;
 
+use core\{
+    di,
+    hook,
+};
 use core_course\external\course_summary_exporter;
 use core_courseformat\base as course_format;
 use core_courseformat\formatactions;
@@ -2032,10 +2036,11 @@ function create_course($data, $editoroptions = NULL) {
     $data->id = $newcourseid;
 
     // Dispatch the hook for post course create actions.
-    $hook = new \core_course\hook\after_course_created(
-        course: $data,
+    di::get(hook\manager::class)->dispatch(
+        new \core_course\hook\after_course_created(
+            course: $data,
+        ),
     );
-    \core\di::get(\core\hook\manager::class)->dispatch($hook);
 
     // Setup the blocks
     blocks_add_default_course_blocks($course);
@@ -2068,8 +2073,9 @@ function create_course($data, $editoroptions = NULL) {
     $data->id = $course->id;
     $handler->instance_form_save($data, true);
 
-    $hook = new \core_course\hook\after_form_submission($data, true);
-    \core\hook\manager::get_instance()->dispatch($hook);
+    di::get(hook\manager::class)->dispatch(
+        new \core_course\hook\after_form_submission($data, true),
+    );
 
     return $course;
 }
@@ -2186,8 +2192,9 @@ function update_course($data, $editoroptions = NULL) {
     $handler = core_course\customfield\course_handler::create();
     $handler->instance_form_save($data);
 
-    $hook = new \core_course\hook\after_form_submission($data);
-    \core\hook\manager::get_instance()->dispatch($hook);
+    di::get(hook\manager::class)->dispatch(
+        new \core_course\hook\after_form_submission($data),
+    );
 
     // Update with the new data
     $DB->update_record('course', $data);
diff --git a/course/modlib.php b/course/modlib.php
index 8b99058b60e..9ec24d70cb0 100644
--- a/course/modlib.php
+++ b/course/modlib.php
@@ -27,8 +27,12 @@
 
 defined('MOODLE_INTERNAL') || die;
 
-use \core_grades\component_gradeitems;
+use core\{
+    di,
+    hook,
+};
 use core_courseformat\formatactions;
+use core_grades\component_gradeitems;
 
 require_once($CFG->dirroot.'/course/lib.php');
 
@@ -725,11 +729,12 @@ function update_moduleinfo($cm, $moduleinfo, $course, $mform = null) {
     }
 
     if ($cm->name != $moduleinfo->name) {
-        $hook = new \core_courseformat\hook\after_cm_name_edited(
-            get_fast_modinfo($course)->get_cm($cm->id),
-            $moduleinfo->name
+        di::get(hook\manager::class)->dispatch(
+            new \core_courseformat\hook\after_cm_name_edited(
+                get_fast_modinfo($course)->get_cm($cm->id),
+                $moduleinfo->name
+            ),
         );
-        \core\hook\manager::get_instance()->dispatch($hook);
     }
 
     $cm->name = $moduleinfo->name;
diff --git a/lib/classes/hook/manager.php b/lib/classes/hook/manager.php
index 259a7a27539..a7a027b7c72 100644
--- a/lib/classes/hook/manager.php
+++ b/lib/classes/hook/manager.php
@@ -45,7 +45,6 @@ use Psr\EventDispatcher\StoppableEventInterface;
 final class manager implements
     EventDispatcherInterface,
     ListenerProviderInterface {
-
     /** @var ?manager the one instance of listener provider and dispatcher */
     private static $instance = null;
 
@@ -81,41 +80,25 @@ final class manager implements
     /**
      * Factory method for testing of hook manager in PHPUnit tests.
      *
+     * Please note that the result of this method should typically be passed to \core\di::set().
+     *
      * @param array $componentfiles list of hook callback files for each component.
-     * @param bool $persist If true, the test instance will be stored in self::$instance. Be sure to call $this->resetAfterTest()
-     *     in your test if you use this.
      * @return self
      */
-    public static function phpunit_get_instance(array $componentfiles, bool $persist = false): manager {
+    public static function phpunit_get_instance(array $componentfiles): manager {
         if (!PHPUNIT_TEST) {
             throw new \coding_exception('Invalid call of manager::phpunit_get_instance() outside of tests');
         }
         $instance = new self();
         $instance->load_callbacks($componentfiles);
-        if ($persist) {
-            self::$instance = $instance;
-        }
         return $instance;
     }
 
-    /**
-     * Reset self::$instance so that future calls to ::get_instance() will return a regular instance.
-     *
-     * @return void
-     */
-    public static function phpunit_reset_instance(): void {
-        if (!PHPUNIT_TEST) {
-            throw new \coding_exception('Invalid call of manager::phpunit_reset_instance() outside of tests');
-        }
-        self::$instance = null;
-    }
-
     /**
      * Override hook callbacks for testing purposes.
      *
      * @param string $hookname
      * @param callable $callback
-     * @return void
      */
     public function phpunit_redirect_hook(string $hookname, callable $callback): void {
         if (!PHPUNIT_TEST) {
@@ -126,8 +109,6 @@ final class manager implements
 
     /**
      * Cancel all redirections of hook callbacks.
-     *
-     * @return void
      */
     public function phpunit_stop_redirections(): void {
         if (!PHPUNIT_TEST) {
@@ -167,7 +148,7 @@ final class manager implements
      *   callable MUST be type-compatible with $event.
      *   Please note that in Moodle the callable must be a string.
      */
-    public function getListenersForEvent(object $event): iterable {
+    public function getListenersForEvent(object $event): iterable { // phpcs:ignore
         // Callbacks are sorted by priority, highest first at load-time.
         $hookclassname = get_class($event);
         $callbacks = $this->get_callbacks_for_hook($hookclassname);
@@ -254,7 +235,7 @@ final class manager implements
             debugging(
                 "Cannot execute callback '$callablename' from '$component'" .
                     "Callback method not callable.",
-                DEBUG_DEVELOPER
+                DEBUG_DEVELOPER,
             );
             return false;
         }
@@ -324,8 +305,6 @@ final class manager implements
 
     /**
      * Initialise list of all callbacks for each hook.
-     *
-     * @return void
      */
     private function init_standard_callbacks(): void {
         global $CFG;
@@ -380,7 +359,6 @@ final class manager implements
      * Load callbacks from component db/hooks.php files.
      *
      * @param array $componentfiles list of all components with their callback files
-     * @return void
      */
     private function load_callbacks(array $componentfiles): void {
         $this->allcallbacks = [];
@@ -504,14 +482,13 @@ final class manager implements
      *
      * @param string $component component where hook callbacks are defined
      * @param string $hookfile file with list of all callbacks for component
-     * @return void
      */
     private function add_component_callbacks(string $component, string $hookfile): void {
         if (!file_exists($hookfile)) {
             return;
         }
 
-        $parsecallbacks = function($hookfile) {
+        $parsecallbacks = function ($hookfile) {
             $callbacks = [];
             include($hookfile);
             return $callbacks;
@@ -577,7 +554,7 @@ final class manager implements
         if (!str_contains($classmethod, '::')) {
             debugging(
                 "Hook callback definition contains invalid 'callback' static class method string in '$component'",
-                DEBUG_DEVELOPER
+                DEBUG_DEVELOPER,
             );
             return null;
         }
@@ -599,7 +576,7 @@ final class manager implements
     public function is_deprecated_plugin_callback(string $plugincallback): bool {
         debugging(
             'is_deprecated_plugin_callback method is deprecated, use get_hooks_deprecating_plugin_callback instead.',
-            DEBUG_DEVELOPER
+            DEBUG_DEVELOPER,
         );
         return (bool)$this->get_hooks_deprecating_plugin_callback($plugincallback);
     }
diff --git a/lib/classes/navigation/views/primary.php b/lib/classes/navigation/views/primary.php
index c8d9402030f..f02bf3ebf34 100644
--- a/lib/classes/navigation/views/primary.php
+++ b/lib/classes/navigation/views/primary.php
@@ -82,7 +82,7 @@ class primary extends view {
 
         // Allow plugins to add nodes to the primary navigation.
         $hook = new \core\hook\navigation\primary_extend($this);
-        \core\hook\manager::get_instance()->dispatch($hook);
+        \core\di::get(\core\hook\manager::class)->dispatch($hook);
 
         // Search and set the active node.
         $this->set_active_node();
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 22b56caf6f7..2bd1749730a 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -28,6 +28,11 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
+use core\{
+    di,
+    hook,
+};
+
 defined('MOODLE_INTERNAL') || die();
 
 // CONSTANTS (Encased in phpdoc proper comments).
@@ -3581,7 +3586,7 @@ function delete_user(stdClass $user) {
     $hook = new \core_user\hook\before_user_deleted(
         user: $user,
     );
-    \core\di::get(\core\hook\manager::class)->dispatch($hook);
+    di::get(hook\manager::class)->dispatch($hook);
 
     // Keep user record before updating it, as we have to pass this to user_deleted event.
     $olduser = clone $user;
@@ -4085,8 +4090,7 @@ function complete_user_login($user, array $extrauserinfo = []) {
     $event->trigger();
 
     // Allow plugins to callback as soon possible after user has completed login.
-    $hook = new \core\hook\user\after_complete_login();
-    \core\hook\manager::get_instance()->dispatch($hook);
+    di::get(\core\hook\manager::class)->dispatch(new \core\hook\user\after_complete_login());
 
     // Check if the user is using a new browser or session (a new MoodleSession cookie is set in that case).
     // If the user is accessing from the same IP, ignore everything (most of the time will be a new session in the same browser).
@@ -7436,8 +7440,8 @@ function get_plugins_with_function($function, $file = 'lib.php', $include = true
         foreach ($pluginfunctions as $plugintype => $plugins) {
             foreach ($plugins as $plugin => $unusedfunction) {
                 $component = $plugintype . '_' . $plugin;
-                if ($hooks = \core\hook\manager::get_instance()->get_hooks_deprecating_plugin_callback($plugincallback)) {
-                    if (\core\hook\manager::get_instance()->is_deprecating_hook_present($component, $plugincallback)) {
+                if ($hooks = di::get(hook\manager::class)->get_hooks_deprecating_plugin_callback($plugincallback)) {
+                    if (di::get(hook\manager::class)->is_deprecating_hook_present($component, $plugincallback)) {
                         // Ignore the old callback, it is there only for older Moodle versions.
                         unset($pluginfunctions[$plugintype][$plugin]);
                     } else {
@@ -7675,8 +7679,9 @@ function component_callback($component, $function, array $params = array(), $def
 
     if ($functionname) {
         if ($migratedtohook) {
-            if ($hooks = \core\hook\manager::get_instance()->get_hooks_deprecating_plugin_callback($function)) {
-                if (\core\hook\manager::get_instance()->is_deprecating_hook_present($component, $function)) {
+            $hookmanager = di::get(hook\manager::class);
+            if ($hooks = $hookmanager->get_hooks_deprecating_plugin_callback($function)) {
+                if ($hookmanager->is_deprecating_hook_present($component, $function)) {
                     // Do not call the old lib.php callback,
                     // it is there for compatibility with older Moodle versions only.
                     return null;
@@ -7776,8 +7781,9 @@ function component_class_callback($classname, $methodname, array $params, $defau
         $functionparts = explode('\\', trim($fullfunction, '\\'));
         $component = $functionparts[0];
         $callback = end($functionparts);
-        if ($hooks = \core\hook\manager::get_instance()->get_hooks_deprecating_plugin_callback($callback)) {
-            if (\core\hook\manager::get_instance()->is_deprecating_hook_present($component, $callback)) {
+        $hookmanager = di::get(hook\manager::class);
+        if ($hooks = $hookmanager->get_hooks_deprecating_plugin_callback($callback)) {
+            if ($hookmanager->is_deprecating_hook_present($component, $callback)) {
                 // Do not call the old class callback,
                 // it is there for compatibility with older Moodle versions only.
                 return null;
diff --git a/lib/phpunit/bootstrap.php b/lib/phpunit/bootstrap.php
index 0ac815e3143..9aedea38c3e 100644
--- a/lib/phpunit/bootstrap.php
+++ b/lib/phpunit/bootstrap.php
@@ -262,6 +262,7 @@ if (PHPUNIT_UTIL) {
 
 // Make sure the hook manager gets initialised before anybody tries to override callbacks,
 // this is not using caches intentionally to help with development.
+// Note: We cannot use DI at this point in the bootstrap either.
 \core\hook\manager::get_instance();
 
 // Is database and dataroot ready for testing?
diff --git a/lib/phpunit/classes/advanced_testcase.php b/lib/phpunit/classes/advanced_testcase.php
index 4f039900f6c..6e4716ac78f 100644
--- a/lib/phpunit/classes/advanced_testcase.php
+++ b/lib/phpunit/classes/advanced_testcase.php
@@ -14,6 +14,11 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
+use core\{
+    di,
+    hook,
+};
+
 /**
  * Advanced PHPUnit test case customised for Moodle.
  *
@@ -486,7 +491,7 @@ abstract class advanced_testcase extends base_testcase {
      * @return void
      */
     public function redirectHook(string $hookname, callable $callback): void {
-        \core\hook\manager::get_instance()->phpunit_redirect_hook($hookname, $callback);
+        di::get(hook\manager::class)->phpunit_redirect_hook($hookname, $callback);
     }
 
     /**
@@ -495,7 +500,7 @@ abstract class advanced_testcase extends base_testcase {
      * @return void
      */
     public function stopHookRedirections(): void {
-        \core\hook\manager::get_instance()->phpunit_stop_redirections();
+        di::get(hook\manager::class)->phpunit_stop_redirections();
     }
 
     /**
@@ -763,4 +768,66 @@ abstract class advanced_testcase extends base_testcase {
 
         return $clock;
     }
+
+    /**
+     * Add a mocked plugintype to Moodle.
+     *
+     * A new plugintype name must be provided with a path to the plugintype's root.
+     *
+     * Please note that tests calling this method must be run in separate isolation mode.
+     * Please avoid using this if at all possible.
+     *
+     * @param string $plugintype The name of the plugintype
+     * @param string $path The path to the plugintype's root
+     */
+    protected function add_mocked_plugintype(
+        string $plugintype,
+        string $path,
+    ): void {
+        require_phpunit_isolation();
+
+        $mockedcomponent = new \ReflectionClass(\core_component::class);
+        $plugintypes = $mockedcomponent->getStaticPropertyValue('plugintypes');
+
+        if (array_key_exists($plugintype, $plugintypes)) {
+            throw new \coding_exception("The plugintype '{$plugintype}' already exists.");
+        }
+
+        $plugintypes[$plugintype] = $path;
+        $mockedcomponent->setStaticPropertyValue('plugintypes', $plugintypes);
+
+        $this->resetDebugging();
+    }
+
+    /**
+     * Add a mocked plugin to Moodle.
+     *
+     * A new plugin name must be provided with a path to the plugin's root.
+     * The plugin type must already exist (or have been mocked separately).
+     *
+     * Please note that tests calling this method must be run in separate isolation mode.
+     * Please avoid using this if at all possible.
+     *
+     * @param string $plugintype The name of the plugintype
+     * @param string $pluginname The name of the plugin
+     * @param string $path The path to the plugin's root
+     */
+    protected function add_mocked_plugin(
+        string $plugintype,
+        string $pluginname,
+        string $path,
+    ): void {
+        require_phpunit_isolation();
+
+        $mockedcomponent = new \ReflectionClass(\core_component::class);
+        $plugins = $mockedcomponent->getStaticPropertyValue('plugins');
+
+        if (!array_key_exists($plugintype, $plugins)) {
+            $plugins[$plugintype] = [];
+        }
+
+        $plugins[$plugintype][$pluginname] = $path;
+        $mockedcomponent->setStaticPropertyValue('plugins', $plugins);
+        $this->resetDebugging();
+    }
 }
diff --git a/lib/phpunit/classes/util.php b/lib/phpunit/classes/util.php
index 1d2b5fd216e..527036ce5be 100644
--- a/lib/phpunit/classes/util.php
+++ b/lib/phpunit/classes/util.php
@@ -23,6 +23,11 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
+use core\{
+    di,
+    hook,
+};
+
 require_once(__DIR__.'/../../testing/classes/util.php');
 require_once(__DIR__ . "/coverage_info.php");
 
@@ -105,10 +110,7 @@ class phpunit_util extends testing_util {
         global $DB, $CFG, $USER, $SITE, $COURSE, $PAGE, $OUTPUT, $SESSION, $FULLME, $FILTERLIB_PRIVATE;
 
         // Stop all hook redirections.
-        \core\hook\manager::get_instance()->phpunit_stop_redirections();
-
-        // Reset the hook manager instance.
-        \core\hook\manager::phpunit_reset_instance();
+        di::get(hook\manager::class)->phpunit_stop_redirections();
 
         // Stop any message redirection.
         self::stop_message_redirection();
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/classes/callbacks.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/classes/callbacks.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/classes/callbacks.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/classes/callbacks.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/classes/hook_callbacks.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook_callbacks.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/classes/hook_callbacks.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hook_callbacks.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/classes/hooks.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hooks.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/classes/hooks.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/classes/hooks.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/db/hooks.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/db/hooks.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/db/hooks.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/db/hooks.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/db/hooks_nocallbacks.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/db/hooks_nocallbacks.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/db/hooks_nocallbacks.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/db/hooks_nocallbacks.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/lib.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/lib.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/lib.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/lib.php
diff --git a/lib/tests/fixtures/fakeplugins/hooktest/version.php b/lib/tests/fixtures/hook/fakeplugins/hooktest/version.php
similarity index 100%
rename from lib/tests/fixtures/fakeplugins/hooktest/version.php
rename to lib/tests/fixtures/hook/fakeplugins/hooktest/version.php
diff --git a/lib/tests/hook/manager_test.php b/lib/tests/hook/manager_test.php
index 076a8a2abcc..de1e29be6ed 100644
--- a/lib/tests/hook/manager_test.php
+++ b/lib/tests/hook/manager_test.php
@@ -16,6 +16,8 @@
 
 namespace core\hook;
 
+use core\di;
+
 /**
  * Hooks tests.
  *
@@ -49,27 +51,8 @@ final class manager_test extends \advanced_testcase {
         $componentfiles = [
             'test_plugin1' => __DIR__ . '/../fixtures/hook/hooks1_valid.php',
         ];
-        $testmanager = manager::phpunit_get_instance($componentfiles, true);
+        $testmanager = manager::phpunit_get_instance($componentfiles);
         $this->assertSame(['test_plugin\\hook\\hook'], $testmanager->get_hooks_with_callbacks());
-        // With $persist = true, get_instance() returns the test instance until reset.
-        $manager = manager::get_instance();
-        $this->assertSame($testmanager, $manager);
-    }
-
-    /**
-     * Test resetting the manager test instance.
-     *
-     * @covers ::phpunit_reset_instance
-     * @return void
-     */
-    public function test_phpunit_reset_instance(): void {
-        $testmanager = manager::phpunit_get_instance([], true);
-        $manager = manager::get_instance();
-        $this->assertSame($testmanager, $manager);
-
-        manager::phpunit_reset_instance();
-        $manager = manager::get_instance();
-        $this->assertNotSame($testmanager, $manager);
     }
 
     /**
@@ -320,42 +303,13 @@ final class manager_test extends \advanced_testcase {
     /**
      * Register a fake plugin called hooktest in the component manager.
      *
-     * @return void
+     * Tests consuming this helpers must run in a separate process.
      */
     protected function setup_hooktest_plugin(): void {
         global $CFG;
 
-        $mockedcomponent = new \ReflectionClass(\core_component::class);
-        $mockedplugintypes = $mockedcomponent->getProperty('plugintypes');
-        $mockedplugintypes->setAccessible(true);
-        $plugintypes = $mockedplugintypes->getValue();
-        $plugintypes['fake'] = "{$CFG->dirroot}/lib/tests/fixtures/fakeplugins";
-        $mockedplugintypes->setValue(null, $plugintypes);
-        $mockedplugins = $mockedcomponent->getProperty('plugins');
-        $mockedplugins->setAccessible(true);
-        $plugins = $mockedplugins->getValue();
-        $plugins['fake'] = ['hooktest' => "{$CFG->dirroot}/lib/tests/fixtures/fakeplugins/hooktest"];
-        $mockedplugins->setValue(null, $plugins);
-        $this->resetDebugging();
-    }
-
-    /**
-     * Remove the fake plugin to avoid interference with other tests.
-     *
-     * @return void
-     */
-    protected function remove_hooktest_plugin(): void {
-        $mockedcomponent = new \ReflectionClass(\core_component::class);
-        $mockedplugintypes = $mockedcomponent->getProperty('plugintypes');
-        $mockedplugintypes->setAccessible(true);
-        $plugintypes = $mockedplugintypes->getValue();
-        unset($plugintypes['fake']);
-        $mockedplugintypes->setValue(null, $plugintypes);
-        $mockedplugins = $mockedcomponent->getProperty('plugins');
-        $mockedplugins->setAccessible(true);
-        $plugins = $mockedplugins->getValue();
-        unset($plugins['fake']);
-        $mockedplugins->setValue(null, $plugins);
+        $this->add_mocked_plugintype('fake', "{$CFG->dirroot}/lib/tests/fixtures/hook/fakeplugins");
+        $this->add_mocked_plugin('fake', 'hooktest', "{$CFG->dirroot}/lib/tests/fixtures/hook/fakeplugins/hooktest");
     }
 
     /**
@@ -363,25 +317,24 @@ final class manager_test extends \advanced_testcase {
      *
      * The original callback should be called, but a debugging message should be output.
      *
-     * @covers ::get_hooks_deprecating_plugin_callback()
-     * @covers ::is_deprecating_hook_present()
-     * @return void
-     * @throws \coding_exception
+     * @runInSeparateProcess
      */
     public function test_migrated_callback(): void {
         $this->resetAfterTest(true);
         // Include plugin hook discovery agent, and the hook that replaces the callback.
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hooks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hooks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php');
         // Register the fake plugin with the component manager.
         $this->setup_hooktest_plugin();
 
         // Register the fake plugin with the hook manager, but don't define any hook callbacks.
-        manager::phpunit_get_instance(
-            [
-                'fake_hooktest' => __DIR__ . '/../fixtures/fakeplugins/hooktest/db/hooks_nocallbacks.php',
-            ],
-            true
+        di::set(
+            manager::class,
+            manager::phpunit_get_instance(
+                [
+                    'fake_hooktest' => __DIR__ . '/../fixtures/hook/fakeplugins/hooktest/db/hooks_nocallbacks.php',
+                ],
+            ),
         );
 
         // Confirm a non-deprecated callback is called as expected.
@@ -393,10 +346,9 @@ final class manager_test extends \advanced_testcase {
             component_callback('fake_hooktest', 'old_callback', [], null, true)
         );
         $this->assertDebuggingCalled(
-            'Callback old_callback in fake_hooktest component should be migrated to new hook '.
+            'Callback old_callback in fake_hooktest component should be migrated to new hook ' .
                 'callback for fake_hooktest\hook\hook_replacing_callback'
         );
-        $this->remove_hooktest_plugin();
     }
 
     /**
@@ -404,26 +356,23 @@ final class manager_test extends \advanced_testcase {
      *
      * The original callback should not be called, and no debugging should be output.
      *
-     * @covers ::get_hooks_deprecating_plugin_callback()
-     * @covers ::is_deprecating_hook_present()
-     * @return void
-     * @throws \coding_exception
+     * @runInSeparateProcess
      */
     public function test_migrated_callback_with_replacement(): void {
         $this->resetAfterTest(true);
         // Include plugin hook discovery agent, and the hook that replaces the callback, and a hook callback for the hook.
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hooks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook_callbacks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hooks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_callback.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook_callbacks.php');
         // Register the fake plugin with the component manager.
         $this->setup_hooktest_plugin();
 
         // Register the fake plugin with the hook manager, including the hook callback.
-        manager::phpunit_get_instance(
-            [
-                'fake_hooktest' => __DIR__ . '/../fixtures/fakeplugins/hooktest/db/hooks.php',
-            ],
-            true
+        di::set(
+            manager::class,
+            manager::phpunit_get_instance([
+                'fake_hooktest' => __DIR__ . '/../fixtures/hook/fakeplugins/hooktest/db/hooks.php',
+            ]),
         );
 
         // Confirm a non-deprecated callback is called as expected.
@@ -432,7 +381,6 @@ final class manager_test extends \advanced_testcase {
         // Confirm the deprecated callback is not called, as expected.
         $this->assertNull(component_callback('fake_hooktest', 'old_callback', [], null, true));
         $this->assertDebuggingNotCalled();
-        $this->remove_hooktest_plugin();
     }
 
     /**
@@ -440,26 +388,23 @@ final class manager_test extends \advanced_testcase {
      *
      * The original class callback should be called, but a debugging message should be output.
      *
-     * @covers ::get_hooks_deprecating_plugin_callback()
-     * @covers ::is_deprecating_hook_present()
-     * @return void
-     * @throws \coding_exception
+     * @runInSeparateProcess
      */
     public function test_migrated_class_callback(): void {
         $this->resetAfterTest(true);
         // Include plugin hook discovery agent, the class containing callbacks, and the hook that replaces the class callback.
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/callbacks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hooks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/callbacks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hooks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php');
         // Register the fake plugin with the component manager.
         $this->setup_hooktest_plugin();
 
         // Register the fake plugin with the hook manager, but don't define any hook callbacks.
-        manager::phpunit_get_instance(
-            [
-                'fake_hooktest' => __DIR__ . '/../fixtures/fakeplugins/hooktest/db/hooks_nocallbacks.php',
-            ],
-            true
+        di::set(
+            manager::class,
+            manager::phpunit_get_instance([
+                'fake_hooktest' => __DIR__ . '/../fixtures/hook/fakeplugins/hooktest/db/hooks_nocallbacks.php',
+            ]),
         );
 
         // Confirm a non-deprecated class callback is called as expected.
@@ -474,10 +419,9 @@ final class manager_test extends \advanced_testcase {
             component_class_callback('fake_hooktest\callbacks', 'old_class_callback', [], null, true)
         );
         $this->assertDebuggingCalled(
-            'Callback callbacks::old_class_callback in fake_hooktest component should be migrated to new hook '.
+            'Callback callbacks::old_class_callback in fake_hooktest component should be migrated to new hook ' .
                 'callback for fake_hooktest\hook\hook_replacing_class_callback'
         );
-        $this->remove_hooktest_plugin();
     }
 
     /**
@@ -485,28 +429,25 @@ final class manager_test extends \advanced_testcase {
      *
      * The original callback should not be called, and no debugging should be output.
      *
-     * @covers ::get_hooks_deprecating_plugin_callback()
-     * @covers ::is_deprecating_hook_present()
-     * @return void
-     * @throws \coding_exception
+     * @runInSeparateProcess
      */
     public function test_migrated_class_callback_with_replacement(): void {
         $this->resetAfterTest(true);
         // Include plugin hook discovery agent, the class containing callbacks, the hook that replaces the class callback,
         // and a hook callback for the new hook.
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/callbacks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hooks.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php');
-        require_once(__DIR__ . '/../fixtures/fakeplugins/hooktest/classes/hook_callbacks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/callbacks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hooks.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook/hook_replacing_class_callback.php');
+        require_once(__DIR__ . '/../fixtures/hook/fakeplugins/hooktest/classes/hook_callbacks.php');
         // Register the fake plugin with the component manager.
         $this->setup_hooktest_plugin();
 
         // Register the fake plugin with the hook manager, including the hook callback.
-        manager::phpunit_get_instance(
-            [
-                'fake_hooktest' => __DIR__ . '/../fixtures/fakeplugins/hooktest/db/hooks.php',
-            ],
-            true
+        di::set(
+            manager::class,
+            manager::phpunit_get_instance([
+                'fake_hooktest' => __DIR__ . '/../fixtures/hook/fakeplugins/hooktest/db/hooks.php',
+            ]),
         );
 
         // Confirm a non-deprecated class callback is called as expected.
@@ -518,14 +459,12 @@ final class manager_test extends \advanced_testcase {
         // Confirm the deprecated class callback is not called, as expected.
         $this->assertNull(component_class_callback('fake_hooktest\callbacks', 'old_class_callback', [], null, true));
         $this->assertDebuggingNotCalled();
-        $this->remove_hooktest_plugin();
     }
 
     /**
      * Normalise the sort order of callbacks to help with asserts.
      *
      * @param array $callbacks
-     * @return void
      */
     private function normalise_callbacks(array &$callbacks): void {
         foreach ($callbacks as &$callback) {
diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 0ec2de0aade..09a2ec88eb5 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -103,8 +103,6 @@ information provided here is intended especially for developers.
 * Deprecated core\hook\manager::is_deprecated_plugin_callback() in favour of ::get_hooks_deprecating_plugin_callback(),
   which will return the classnames of hooks deprecating a callback, or null if it's not deprecated. The return value can be cast
   to bool if the original functionality is desired.
-* core\hook\manager::phpunit_get_instance() now sets self::$instance to the mocked instance if the optional $persist argument is
-  true, so future calls to ::get_instance() will return it.
 * The triggerSelector method in the `core/comboboxsearch/search_combobox` JS module is deprecated. It was not used.
 * PHPUnit has been upgraded to 9.6 (see MDL-81266 for details).
   The main goal of the update is to allow developers to know in advance,
diff --git a/mod/quiz/classes/grade_calculator.php b/mod/quiz/classes/grade_calculator.php
index 122088297af..69a8158ad91 100644
--- a/mod/quiz/classes/grade_calculator.php
+++ b/mod/quiz/classes/grade_calculator.php
@@ -17,6 +17,10 @@
 namespace mod_quiz;
 
 use coding_exception;
+use core\{
+    di,
+    hook,
+};
 use mod_quiz\event\quiz_grade_updated;
 use mod_quiz\hook\structure_modified;
 use question_engine_data_mapper;
@@ -100,7 +104,7 @@ class grade_calculator {
             component_class_callback($callbackclass, 'callback', [$quiz->id], null, true);
         }
 
-        \core\hook\manager::get_instance()->dispatch(new structure_modified($this->quizobj->get_structure()));
+        di::get(hook\manager::class)->dispatch(new structure_modified($this->quizobj->get_structure()));
     }
 
     /**
diff --git a/mod/quiz/classes/quiz_attempt.php b/mod/quiz/classes/quiz_attempt.php
index 08c40dac12d..6b93de93761 100644
--- a/mod/quiz/classes/quiz_attempt.php
+++ b/mod/quiz/classes/quiz_attempt.php
@@ -21,6 +21,10 @@ use block_contents;
 use cm_info;
 use coding_exception;
 use context_module;
+use core\{
+    di,
+    hook,
+};
 use Exception;
 use html_writer;
 use mod_quiz\hook\attempt_state_changed;
@@ -1787,7 +1791,7 @@ class quiz_attempt {
             // Trigger event.
             $this->fire_state_transition_event('\mod_quiz\event\attempt_submitted', $timestamp, $studentisonline);
 
-            \core\hook\manager::get_instance()->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
+            di::get(hook\manager::class)->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
             // Tell any access rules that care that the attempt is over.
             $this->get_access_manager($timestamp)->current_attempt_finished();
         }
@@ -1835,7 +1839,7 @@ class quiz_attempt {
 
         $this->fire_state_transition_event('\mod_quiz\event\attempt_becameoverdue', $timestamp, $studentisonline);
 
-        \core\hook\manager::get_instance()->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
+        di::get(hook\manager::class)->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
         $transaction->allow_commit();
 
         quiz_send_overdue_message($this);
@@ -1859,7 +1863,7 @@ class quiz_attempt {
 
         $this->fire_state_transition_event('\mod_quiz\event\attempt_abandoned', $timestamp, $studentisonline);
 
-        \core\hook\manager::get_instance()->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
+        di::get(hook\manager::class)->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
 
         $transaction->allow_commit();
     }
@@ -1890,7 +1894,7 @@ class quiz_attempt {
 
         $this->fire_state_transition_event('\mod_quiz\event\attempt_reopened', $timestamp, false);
 
-        \core\hook\manager::get_instance()->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
+        di::get(hook\manager::class)->dispatch(new attempt_state_changed($originalattempt, $this->attempt));
         $timeclose = $this->get_access_manager($timestamp)->get_end_time($this->attempt);
         if ($timeclose && $timestamp > $timeclose) {
             $this->process_finish($timestamp, false, $timeclose);
diff --git a/mod/quiz/locallib.php b/mod/quiz/locallib.php
index 7459560f2d3..7d60989a26b 100644
--- a/mod/quiz/locallib.php
+++ b/mod/quiz/locallib.php
@@ -35,6 +35,10 @@ require_once($CFG->libdir . '/completionlib.php');
 require_once($CFG->libdir . '/filelib.php');
 require_once($CFG->libdir . '/questionlib.php');
 
+use core\{
+    di,
+    hook,
+};
 use core_question\local\bank\condition;
 use mod_quiz\access_manager;
 use mod_quiz\event\attempt_submitted;
@@ -147,7 +151,7 @@ function quiz_create_attempt(quiz_settings $quizobj, $attemptnumber, $lastattemp
         $attempt->timecheckstate = $timeclose;
     }
 
-    \core\hook\manager::get_instance()->dispatch(new attempt_state_changed(null, $attempt));
+    di::get(hook\manager::class)->dispatch(new attempt_state_changed(null, $attempt));
 
     return $attempt;
 }
@@ -459,7 +463,7 @@ function quiz_delete_attempt($attempt, $quiz) {
             component_class_callback($callbackclass, 'callback', [$quiz->id], null, true);
         }
 
-        \core\hook\manager::get_instance()->dispatch(new attempt_state_changed($attempt, null));
+        di::get(hook\manager::class)->dispatch(new attempt_state_changed($attempt, null));
     }
 
     // Search quiz_attempts for other instances by this user.