diff --git a/core/.phpstan-baseline.php b/core/.phpstan-baseline.php
index c62f3ab5c5d..2a9e9199916 100644
--- a/core/.phpstan-baseline.php
+++ b/core/.phpstan-baseline.php
@@ -61473,12 +61473,6 @@ $ignoreErrors[] = [
 	'count' => 2,
 	'path' => __DIR__ . '/tests/Drupal/Tests/Core/Entity/EntityStorageBaseTest.php',
 ];
-$ignoreErrors[] = [
-	// identifier: method.deprecated
-	'message' => '#^Call to deprecated method getMockForAbstractClass\\(\\) of class PHPUnit\\\\Framework\\\\TestCase\\.$#',
-	'count' => 2,
-	'path' => __DIR__ . '/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php',
-];
 $ignoreErrors[] = [
 	// identifier: missingType.return
 	'message' => '#^Method Drupal\\\\Tests\\\\Core\\\\Entity\\\\TestEntityForm\\:\\:getBaseFormId\\(\\) has no return type specified\\.$#',
@@ -61515,12 +61509,6 @@ $ignoreErrors[] = [
 	'count' => 1,
 	'path' => __DIR__ . '/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php',
 ];
-$ignoreErrors[] = [
-	// identifier: method.deprecated
-	'message' => '#^Call to deprecated method getMockForAbstractClass\\(\\) of class PHPUnit\\\\Framework\\\\TestCase\\.$#',
-	'count' => 1,
-	'path' => __DIR__ . '/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php',
-];
 $ignoreErrors[] = [
 	// identifier: missingType.return
 	'message' => '#^Method Drupal\\\\Tests\\\\Core\\\\Entity\\\\EntityTypeTest\\:\\:providerTestGet\\(\\) has no return type specified\\.$#',
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
index ab84e16880d..7ece81b20ab 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityTypeManagerTest.php
@@ -171,12 +171,11 @@ class EntityTypeManagerTest extends UnitTestCase {
    * @covers ::getStorage
    */
   public function testGetStorage(): void {
-    $class = $this->getTestHandlerClass();
     $entity = $this->prophesize(EntityTypeInterface::class);
-    $entity->getHandlerClass('storage')->willReturn($class);
+    $entity->getHandlerClass('storage')->willReturn(StubEntityHandlerBase::class);
     $this->setUpEntityTypeDefinitions(['test_entity_type' => $entity]);
 
-    $this->assertInstanceOf($class, $this->entityTypeManager->getStorage('test_entity_type'));
+    $this->assertInstanceOf(StubEntityHandlerBase::class, $this->entityTypeManager->getStorage('test_entity_type'));
   }
 
   /**
@@ -185,12 +184,11 @@ class EntityTypeManagerTest extends UnitTestCase {
    * @covers ::getListBuilder
    */
   public function testGetListBuilder(): void {
-    $class = $this->getTestHandlerClass();
     $entity = $this->prophesize(EntityTypeInterface::class);
-    $entity->getHandlerClass('list_builder')->willReturn($class);
+    $entity->getHandlerClass('list_builder')->willReturn(StubEntityHandlerBase::class);
     $this->setUpEntityTypeDefinitions(['test_entity_type' => $entity]);
 
-    $this->assertInstanceOf($class, $this->entityTypeManager->getListBuilder('test_entity_type'));
+    $this->assertInstanceOf(StubEntityHandlerBase::class, $this->entityTypeManager->getListBuilder('test_entity_type'));
   }
 
   /**
@@ -199,12 +197,11 @@ class EntityTypeManagerTest extends UnitTestCase {
    * @covers ::getViewBuilder
    */
   public function testGetViewBuilder(): void {
-    $class = $this->getTestHandlerClass();
     $entity = $this->prophesize(EntityTypeInterface::class);
-    $entity->getHandlerClass('view_builder')->willReturn($class);
+    $entity->getHandlerClass('view_builder')->willReturn(StubEntityHandlerBase::class);
     $this->setUpEntityTypeDefinitions(['test_entity_type' => $entity]);
 
-    $this->assertInstanceOf($class, $this->entityTypeManager->getViewBuilder('test_entity_type'));
+    $this->assertInstanceOf(StubEntityHandlerBase::class, $this->entityTypeManager->getViewBuilder('test_entity_type'));
   }
 
   /**
@@ -213,12 +210,11 @@ class EntityTypeManagerTest extends UnitTestCase {
    * @covers ::getAccessControlHandler
    */
   public function testGetAccessControlHandler(): void {
-    $class = $this->getTestHandlerClass();
     $entity = $this->prophesize(EntityTypeInterface::class);
-    $entity->getHandlerClass('access')->willReturn($class);
+    $entity->getHandlerClass('access')->willReturn(StubEntityHandlerBase::class);
     $this->setUpEntityTypeDefinitions(['test_entity_type' => $entity]);
 
-    $this->assertInstanceOf($class, $this->entityTypeManager->getAccessControlHandler('test_entity_type'));
+    $this->assertInstanceOf(StubEntityHandlerBase::class, $this->entityTypeManager->getAccessControlHandler('test_entity_type'));
   }
 
   /**
@@ -302,16 +298,15 @@ class EntityTypeManagerTest extends UnitTestCase {
    * @covers ::getHandler
    */
   public function testGetHandler(): void {
-    $class = get_class($this->getMockForAbstractClass(TestEntityHandlerBase::class));
     $apple = $this->prophesize(EntityTypeInterface::class);
-    $apple->getHandlerClass('storage')->willReturn($class);
+    $apple->getHandlerClass('storage')->willReturn(StubEntityHandlerBase::class);
 
     $this->setUpEntityTypeDefinitions([
       'apple' => $apple,
     ]);
 
     $apple_controller = $this->entityTypeManager->getHandler('apple', 'storage');
-    $this->assertInstanceOf($class, $apple_controller);
+    $this->assertInstanceOf(StubEntityHandlerBase::class, $apple_controller);
     $this->assertInstanceOf(ModuleHandlerInterface::class, $apple_controller->moduleHandler);
     $this->assertInstanceOf(TranslationInterface::class, $apple_controller->stringTranslation);
   }
@@ -446,33 +441,6 @@ class EntityTypeManagerTest extends UnitTestCase {
     $this->entityTypeManager->getDefinition('pear', TRUE);
   }
 
-  /**
-   * Gets a mock controller class name.
-   *
-   * @return string
-   *   A mock controller class name.
-   */
-  protected function getTestHandlerClass(): string {
-    return get_class($this->getMockForAbstractClass(EntityHandlerBase::class));
-  }
-
-}
-
-/**
- * Provides a test entity handler.
- */
-abstract class TestEntityHandlerBase extends EntityHandlerBase {
-
-  /**
-   * {@inheritdoc}
-   */
-  public $moduleHandler;
-
-  /**
-   * {@inheritdoc}
-   */
-  public $stringTranslation;
-
 }
 
 /**
diff --git a/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php b/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
index d334ed95176..e3581b32667 100644
--- a/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
+++ b/core/tests/Drupal/Tests/Core/Entity/EntityTypeTest.php
@@ -159,17 +159,16 @@ class EntityTypeTest extends UnitTestCase {
    * Tests the getHandler() method.
    */
   public function testGetHandler(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([
       'handlers' => [
-        'storage' => $controller,
+        'storage' => StubEntityHandlerBase::class,
         'form' => [
-          'default' => $controller,
+          'default' => StubEntityHandlerBase::class,
         ],
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getHandlerClass('storage'));
-    $this->assertSame($controller, $entity_type->getHandlerClass('form', 'default'));
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getHandlerClass('storage'));
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getHandlerClass('form', 'default'));
     $this->assertNull($entity_type->getHandlerClass('foo'));
     $this->assertNull($entity_type->getHandlerClass('foo', 'bar'));
   }
@@ -178,76 +177,70 @@ class EntityTypeTest extends UnitTestCase {
    * Tests the getStorageClass() method.
    */
   public function testGetStorageClass(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([
       'handlers' => [
-        'storage' => $controller,
+        'storage' => StubEntityHandlerBase::class,
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getStorageClass());
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getStorageClass());
   }
 
   /**
    * Tests the setStorageClass() method.
    */
   public function testSetStorageClass(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([]);
-    $this->assertSame($entity_type, $entity_type->setStorageClass($controller));
+    $this->assertSame($entity_type, $entity_type->setStorageClass(StubEntityHandlerBase::class));
   }
 
   /**
    * Tests the getListBuilderClass() method.
    */
   public function testGetListBuilderClass(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([
       'handlers' => [
-        'list_builder' => $controller,
+        'list_builder' => StubEntityHandlerBase::class,
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getListBuilderClass());
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getListBuilderClass());
   }
 
   /**
    * Tests the getAccessControlClass() method.
    */
   public function testGetAccessControlClass(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([
       'handlers' => [
-        'access' => $controller,
+        'access' => StubEntityHandlerBase::class,
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getAccessControlClass());
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getAccessControlClass());
   }
 
   /**
    * Tests the getFormClass() method.
    */
   public function testGetFormClass(): void {
-    $controller = $this->getTestHandlerClass();
     $operation = 'default';
     $entity_type = $this->setUpEntityType([
       'handlers' => [
         'form' => [
-          $operation => $controller,
+          $operation => StubEntityHandlerBase::class,
         ],
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getFormClass($operation));
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getFormClass($operation));
   }
 
   /**
    * Tests the hasFormClasses() method.
    */
   public function testHasFormClasses(): void {
-    $controller = $this->getTestHandlerClass();
     $operation = 'default';
     $entity_type1 = $this->setUpEntityType([
       'handlers' => [
         'form' => [
-          $operation => $controller,
+          $operation => StubEntityHandlerBase::class,
         ],
       ],
     ]);
@@ -262,13 +255,12 @@ class EntityTypeTest extends UnitTestCase {
    * Tests the getViewBuilderClass() method.
    */
   public function testGetViewBuilderClass(): void {
-    $controller = $this->getTestHandlerClass();
     $entity_type = $this->setUpEntityType([
       'handlers' => [
-        'view_builder' => $controller,
+        'view_builder' => StubEntityHandlerBase::class,
       ],
     ]);
-    $this->assertSame($controller, $entity_type->getViewBuilderClass());
+    $this->assertSame(StubEntityHandlerBase::class, $entity_type->getViewBuilderClass());
   }
 
   /**
@@ -440,16 +432,6 @@ class EntityTypeTest extends UnitTestCase {
     ];
   }
 
-  /**
-   * Gets a mock controller class name.
-   *
-   * @return string
-   *   A mock controller class name.
-   */
-  protected function getTestHandlerClass(): string {
-    return get_class($this->getMockForAbstractClass('Drupal\Core\Entity\EntityHandlerBase'));
-  }
-
   /**
    * @covers ::setLinkTemplate
    */
diff --git a/core/tests/Drupal/Tests/Core/Entity/StubEntityHandlerBase.php b/core/tests/Drupal/Tests/Core/Entity/StubEntityHandlerBase.php
new file mode 100644
index 00000000000..df10dca139c
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Entity/StubEntityHandlerBase.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\Core\Entity;
+
+use Drupal\Core\Entity\EntityHandlerBase;
+
+/**
+ * A stub base entity handler for testing purposes.
+ */
+class StubEntityHandlerBase extends EntityHandlerBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public $moduleHandler;
+
+  /**
+   * {@inheritdoc}
+   */
+  public $stringTranslation;
+
+}