diff --git a/lib/classes/plugininfo/base.php b/lib/classes/plugininfo/base.php
index b7ce65ff9bf..910c5b2959c 100644
--- a/lib/classes/plugininfo/base.php
+++ b/lib/classes/plugininfo/base.php
@@ -77,6 +77,12 @@ abstract class base {
     /** @var int Move a plugin down in the plugin order */
     public const MOVE_DOWN = 1;
 
+    /** @var array hold $plugin->supported in version.php */
+    public $supported;
+
+    /** @var int hold $plugin->incompatible in version.php  */
+    public $incompatible;
+
     /**
      * Whether this plugintype supports its plugins being disabled.
      *
diff --git a/lib/tests/behat/behat_accessibility.php b/lib/tests/behat/behat_accessibility.php
index 022a7aed7f1..454cf790982 100644
--- a/lib/tests/behat/behat_accessibility.php
+++ b/lib/tests/behat/behat_accessibility.php
@@ -142,7 +142,7 @@ EOF;
         }
 
         if ($results->exception !== null) {
-            throw new ExpectationException($results->exception, $this->session);
+            throw new ExpectationException($results->exception, $this->getSession());
         }
 
         $violations = $results->violations;
diff --git a/lib/tests/component_test.php b/lib/tests/component_test.php
index 9463ca885d7..bdf3638973a 100644
--- a/lib/tests/component_test.php
+++ b/lib/tests/component_test.php
@@ -23,6 +23,7 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  *
  * @covers \core_component
+ * @runTestsInSeparateProcesses
  */
 class component_test extends advanced_testcase {
 
@@ -33,25 +34,6 @@ class component_test extends advanced_testcase {
      */
     const SUBSYSTEMCOUNT = 77;
 
-    public function setUp(): void {
-        $psr0namespaces = new ReflectionProperty('core_component', 'psr0namespaces');
-        $psr0namespaces->setAccessible(true);
-        $this->oldpsr0namespaces = $psr0namespaces->getValue(null);
-
-        $psr4namespaces = new ReflectionProperty('core_component', 'psr4namespaces');
-        $psr4namespaces->setAccessible(true);
-        $this->oldpsr4namespaces = $psr4namespaces->getValue(null);
-    }
-    public function tearDown(): void {
-        $psr0namespaces = new ReflectionProperty('core_component', 'psr0namespaces');
-        $psr0namespaces->setAccessible(true);
-        $psr0namespaces->setValue(null, $this->oldpsr0namespaces);
-
-        $psr4namespaces = new ReflectionProperty('core_component', 'psr4namespaces');
-        $psr4namespaces->setAccessible(true);
-        $psr4namespaces->setValue(null, $this->oldpsr4namespaces);
-    }
-
     public function test_get_core_subsystems() {
         global $CFG;
 
diff --git a/lib/tests/fixtures/test_renderer_factory.php b/lib/tests/fixtures/test_renderer_factory.php
index a3a1079ee8d..4d32622c496 100644
--- a/lib/tests/fixtures/test_renderer_factory.php
+++ b/lib/tests/fixtures/test_renderer_factory.php
@@ -43,7 +43,7 @@ class test_output_factory extends renderer_factory_base {
      *
      */
     public function __construct() {
-        $this->prefixes = array('theme_child', 'theme_parent');
+        // Leave the construct empty to override the parent.
     }
 
     /**
@@ -93,6 +93,7 @@ class test_output_factory extends renderer_factory_base {
      * @return string[] of classnames
      */
     public function get_theme_overridden_renderer_factory_search_paths($component, $subtype = null, $target = null) {
+        $themeprefixes = ['theme_child', 'theme_parent'];
         $searchtargets = array();
         $classnames = $this->standard_renderer_classnames($component, $subtype);
 
@@ -102,7 +103,7 @@ class test_output_factory extends renderer_factory_base {
         // when loading the theme configs.
 
         // First try the renderers with correct suffix.
-        foreach ($this->prefixes as $prefix) {
+        foreach ($themeprefixes as $prefix) {
             foreach ($classnames as $classnamedetails) {
                 if ($classnamedetails['validwithprefix']) {
                     if ($classnamedetails['autoloaded']) {
@@ -122,7 +123,7 @@ class test_output_factory extends renderer_factory_base {
         }
 
         // Then try general renderer.
-        foreach ($this->prefixes as $prefix) {
+        foreach ($themeprefixes as $prefix) {
             foreach ($classnames as $classnamedetails) {
                 if ($classnamedetails['validwithprefix']) {
                     if ($classnamedetails['autoloaded']) {
diff --git a/lib/tests/myprofilelib_test.php b/lib/tests/myprofilelib_test.php
index 04a96be0609..a444ef28da2 100644
--- a/lib/tests/myprofilelib_test.php
+++ b/lib/tests/myprofilelib_test.php
@@ -44,14 +44,12 @@ class myprofilelib_test extends \advanced_testcase {
      * @var \core_user\output\myprofile\tree The navigation tree.
      */
     private $tree;
-
     public function setUp(): void {
         // Set the $PAGE->url value so core_myprofile_navigation() doesn't complain.
         global $PAGE;
         $PAGE->set_url('/test');
 
         $this->user = $this->getDataGenerator()->create_user();
-        $this->user2 = $this->getDataGenerator()->create_user();
         $this->course = $this->getDataGenerator()->create_course();
         $this->tree = new \core_user\output\myprofile\tree();
         $this->resetAfterTest();
@@ -87,7 +85,8 @@ class myprofilelib_test extends \advanced_testcase {
      * profile of another another user.
      */
     public function test_core_myprofile_navigation_course_without_permission() {
-        $this->setUser($this->user2);
+        // User without permission.
+        $this->setUser($this->getDataGenerator()->create_user());
         $iscurrentuser = false;
 
         core_myprofile_navigation($this->tree, $this->user, $iscurrentuser, $this->course);
@@ -146,7 +145,7 @@ class myprofilelib_test extends \advanced_testcase {
      */
     public function test_core_myprofile_navigation_preference_without_permission() {
         // Login as link for a user who doesn't have the capability to login as.
-        $this->setUser($this->user2);
+        $this->setUser($this->getDataGenerator()->create_user());
         $iscurrentuser = false;
 
         core_myprofile_navigation($this->tree, $this->user, $iscurrentuser, $this->course);
@@ -211,7 +210,7 @@ class myprofilelib_test extends \advanced_testcase {
         $identityfields = explode(',', $CFG->showuseridentity);
 
         // User without permission.
-        $this->setUser($this->user2);
+        $this->setUser($this->getDataGenerator()->create_user());
         core_myprofile_navigation($this->tree, $this->user, $iscurrentuser, null);
         $reflector = new \ReflectionObject($this->tree);
         $nodes = $reflector->getProperty('nodes');
@@ -300,7 +299,7 @@ class myprofilelib_test extends \advanced_testcase {
     public function test_core_myprofile_navigationn_login_activity_without_permission() {
         // User without permission.
         set_config("hiddenuserfields", "firstaccess,lastaccess,lastip");
-        $this->setUser($this->user2);
+        $this->setUser($this->getDataGenerator()->create_user());
         $iscurrentuser = false;
 
         core_myprofile_navigation($this->tree, $this->user, $iscurrentuser, null);
diff --git a/lib/tests/navigationlib_test.php b/lib/tests/navigationlib_test.php
index 3b75dabddf8..ed875a7a8e1 100644
--- a/lib/tests/navigationlib_test.php
+++ b/lib/tests/navigationlib_test.php
@@ -711,7 +711,6 @@ class exposed_global_navigation extends global_navigation {
             $page = $PAGE;
         }
         parent::__construct($page);
-        $this->cache = new navigation_cache('unittest_nav');
     }
     public function __call($method, $arguments) {
         if (strpos($method, $this->exposedkey) !== false) {
@@ -763,9 +762,9 @@ class mock_initialise_global_navigation extends global_navigation {
  */
 class exposed_navbar extends navbar {
     protected $exposedkey = 'exposed_';
+
     public function __construct(\moodle_page $page) {
         parent::__construct($page);
-        $this->cache = new navigation_cache('unittest_nav');
     }
     public function __call($method, $arguments) {
         if (strpos($method, $this->exposedkey) !== false) {
@@ -793,7 +792,6 @@ class exposed_settings_navigation extends settings_navigation {
     public function __construct() {
         global $PAGE;
         parent::__construct($PAGE);
-        $this->cache = new navigation_cache('unittest_nav');
     }
     public function __call($method, $arguments) {
         if (strpos($method, $this->exposedkey) !== false) {
diff --git a/lib/tests/persistent_test.php b/lib/tests/persistent_test.php
index 8d03320569e..78f5b52a4b9 100644
--- a/lib/tests/persistent_test.php
+++ b/lib/tests/persistent_test.php
@@ -700,6 +700,27 @@ class core_testable_persistent extends persistent {
 
     const TABLE = 'phpunit_persistent';
 
+    /** @var bool before validate status. */
+    public ?bool $beforevalidate;
+
+    /** @var bool before create status. */
+    public ?bool $beforecreate;
+
+    /** @var bool before update status. */
+    public ?bool $beforeupdate;
+
+    /** @var bool before delete status. */
+    public ?bool $beforedelete;
+
+    /** @var bool after create status. */
+    public ?bool $aftercreate;
+
+    /** @var bool after update status. */
+    public ?bool $afterupdate;
+
+    /** @var bool after delete status. */
+    public ?bool $afterdelete;
+
     protected static function define_properties() {
         return array(
             'shortname' => array(