diff --git a/core/.phpstan-baseline.php b/core/.phpstan-baseline.php
index d9b3b03d9e1d8fb1bfa2bdba4411535decd111dc..6b0f8073d60048fd418425931184848733a6bfc5 100644
--- a/core/.phpstan-baseline.php
+++ b/core/.phpstan-baseline.php
@@ -2521,18 +2521,6 @@
 	'count' => 1,
 	'path' => __DIR__ . '/tests/Drupal/Tests/Component/Plugin/Factory/ReflectionFactoryTest.php',
 ];
-$ignoreErrors[] = [
-	// identifier: method.deprecated
-	'message' => '#^Call to deprecated method getMockForAbstractClass\\(\\) of class PHPUnit\\\\Framework\\\\TestCase\\.$#',
-	'count' => 4,
-	'path' => __DIR__ . '/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php',
-];
-$ignoreErrors[] = [
-	// identifier: method.deprecated
-	'message' => '#^Call to deprecated method getMockForAbstractClass\\(\\) of class PHPUnit\\\\Framework\\\\MockObject\\\\MockBuilder\\.$#',
-	'count' => 2,
-	'path' => __DIR__ . '/tests/Drupal/Tests/Component/Plugin/PluginManagerBaseTest.php',
-];
 $ignoreErrors[] = [
 	'message' => '#^Missing cache backend declaration for performance\\.$#',
 	'count' => 1,
diff --git a/core/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php b/core/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php
index 488361d6de9ee8f98b09dfec943b7074d31e0764..51ff3575f96982b28bcf6a26c33c665ff58115b0 100644
--- a/core/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php
+++ b/core/tests/Drupal/Tests/Component/Plugin/PluginBaseTest.php
@@ -17,11 +17,11 @@ class PluginBaseTest extends TestCase {
    * @covers ::getPluginId
    */
   public function testGetPluginId($plugin_id, $expected): void {
-    $plugin_base = $this->getMockForAbstractClass('Drupal\Component\Plugin\PluginBase', [
+    $plugin_base = new StubPluginBase(
       [],
       $plugin_id,
       [],
-    ]);
+    );
 
     $this->assertEquals($expected, $plugin_base->getPluginId());
   }
@@ -43,12 +43,11 @@ public static function providerTestGetPluginId() {
    * @coves ::getBaseId
    */
   public function testGetBaseId($plugin_id, $expected): void {
-    /** @var \Drupal\Component\Plugin\PluginBase|\PHPUnit\Framework\MockObject\MockObject $plugin_base */
-    $plugin_base = $this->getMockForAbstractClass('Drupal\Component\Plugin\PluginBase', [
+    $plugin_base = new StubPluginBase(
       [],
       $plugin_id,
       [],
-    ]);
+    );
 
     $this->assertEquals($expected, $plugin_base->getBaseId());
   }
@@ -70,12 +69,11 @@ public static function providerTestGetBaseId() {
    * @covers ::getDerivativeId
    */
   public function testGetDerivativeId($plugin_id = NULL, $expected = NULL): void {
-    /** @var \Drupal\Component\Plugin\PluginBase|\PHPUnit\Framework\MockObject\MockObject $plugin_base */
-    $plugin_base = $this->getMockForAbstractClass('Drupal\Component\Plugin\PluginBase', [
+    $plugin_base = new StubPluginBase(
       [],
       $plugin_id,
       [],
-    ]);
+    );
 
     $this->assertEquals($expected, $plugin_base->getDerivativeId());
   }
@@ -96,11 +94,11 @@ public static function providerTestGetDerivativeId() {
    * @covers ::getPluginDefinition
    */
   public function testGetPluginDefinition(): void {
-    $plugin_base = $this->getMockForAbstractClass('Drupal\Component\Plugin\PluginBase', [
+    $plugin_base = new StubPluginBase(
       [],
       'plugin_id',
       ['value', ['key' => 'value']],
-    ]);
+    );
 
     $this->assertEquals(['value', ['key' => 'value']], $plugin_base->getPluginDefinition());
   }
diff --git a/core/tests/Drupal/Tests/Component/Plugin/PluginManagerBaseTest.php b/core/tests/Drupal/Tests/Component/Plugin/PluginManagerBaseTest.php
index 39fdeddc08dd0d9b1240534e7235b0d144e7a9c6..9842f252a8399427943f0c7c483509f7e2b3d033 100644
--- a/core/tests/Drupal/Tests/Component/Plugin/PluginManagerBaseTest.php
+++ b/core/tests/Drupal/Tests/Component/Plugin/PluginManagerBaseTest.php
@@ -6,7 +6,6 @@
 
 use Drupal\Component\Plugin\Exception\PluginNotFoundException;
 use Drupal\Component\Plugin\Mapper\MapperInterface;
-use Drupal\Component\Plugin\PluginManagerBase;
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
 
@@ -51,8 +50,7 @@ public function getMockFactoryInterface($expects_count) {
    * @covers ::createInstance
    */
   public function testCreateInstance(): void {
-    $manager = $this->getMockBuilder('Drupal\Component\Plugin\PluginManagerBase')
-      ->getMockForAbstractClass();
+    $manager = new StubPluginManagerBase();
     // PluginManagerBase::createInstance() looks for a factory object and then
     // calls createInstance() on it. So we have to mock a factory object.
     $factory_ref = new \ReflectionProperty($manager, 'factory');
@@ -118,9 +116,7 @@ public function testGetInstanceWithoutMapperShouldThrowException(): void {
       'foo' => 'F00',
       'bar' => 'bAr',
     ];
-    /** @var \Drupal\Component\Plugin\PluginManagerBase $manager */
-    $manager = $this->getMockBuilder(PluginManagerBase::class)
-      ->getMockForAbstractClass();
+    $manager = new StubPluginManagerBase();
     // Set the expected exception thrown by ::getInstance.
     $this->expectException(\BadMethodCallException::class);
     $this->expectExceptionMessage(sprintf('%s does not support this method unless %s::$mapper is set.', get_class($manager), get_class($manager)));
diff --git a/core/tests/Drupal/Tests/Component/Plugin/StubPluginBase.php b/core/tests/Drupal/Tests/Component/Plugin/StubPluginBase.php
new file mode 100644
index 0000000000000000000000000000000000000000..1c9e87cea4165ea1e13dfb410155a62bb03b416c
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Plugin/StubPluginBase.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\Component\Plugin;
+
+use Drupal\Component\Plugin\PluginBase;
+
+/**
+ * A class extending PluginBase for testing purposes.
+ */
+class StubPluginBase extends PluginBase {
+}
diff --git a/core/tests/Drupal/Tests/Component/Plugin/StubPluginManagerBase.php b/core/tests/Drupal/Tests/Component/Plugin/StubPluginManagerBase.php
new file mode 100644
index 0000000000000000000000000000000000000000..a4ae95b3e529de499788776f0a61c85429fae0fe
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Plugin/StubPluginManagerBase.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\Component\Plugin;
+
+use Drupal\Component\Plugin\PluginManagerBase;
+
+/**
+ * A class extending PluginManagerBase for testing purposes.
+ */
+class StubPluginManagerBase extends PluginManagerBase {
+}