diff --git a/core/tests/Drupal/KernelTests/KernelTestBase.php b/core/tests/Drupal/KernelTests/KernelTestBase.php
index 1a83d4ab62d70718d2e3200f7b1fc2ba36630f5d..c98b77fd9fef8c64e5fbfb2f2b53c4c7fcdde4cc 100644
--- a/core/tests/Drupal/KernelTests/KernelTestBase.php
+++ b/core/tests/Drupal/KernelTests/KernelTestBase.php
@@ -24,7 +24,6 @@
 use Drupal\Tests\Traits\PhpUnitWarnings;
 use Drupal\TestTools\Comparator\MarkupInterfaceComparator;
 use Drupal\TestTools\Extension\SchemaInspector;
-use Drupal\TestTools\Random;
 use Drupal\TestTools\TestVarDumper;
 use PHPUnit\Framework\Exception;
 use PHPUnit\Framework\TestCase;
@@ -267,7 +266,9 @@ protected function setUp(): void {
    */
   public function __get(string $name) {
     if ($name === 'randomGenerator') {
-      return Random::getGenerator();
+      @trigger_error('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445', E_USER_DEPRECATED);
+
+      return $this->getRandomGenerator();
     }
   }
 
diff --git a/core/tests/Drupal/KernelTests/KernelTestBaseTest.php b/core/tests/Drupal/KernelTests/KernelTestBaseTest.php
index 5baab80ede80e05c6b969709f8660b47a231423a..689cf8b953e073e50b867d75b27aeb4502b7ccd4 100644
--- a/core/tests/Drupal/KernelTests/KernelTestBaseTest.php
+++ b/core/tests/Drupal/KernelTests/KernelTestBaseTest.php
@@ -3,6 +3,7 @@
 namespace Drupal\KernelTests;
 
 use Drupal\Component\FileCache\FileCacheFactory;
+use Drupal\Component\Utility\Random;
 use Drupal\Core\Database\Database;
 use GuzzleHttp\Exception\GuzzleException;
 use Drupal\Tests\StreamCapturer;
@@ -365,4 +366,17 @@ public function testDatabaseDriverModuleEnabled() {
     $this->assertSame(1, \Drupal::service('extension.list.module')->get($module)->status);
   }
 
+  /**
+   * Tests the deprecation of accessing the randomGenerator property directly.
+   *
+   * @group legacy
+   */
+  public function testGetRandomGeneratorPropertyDeprecation() {
+    $this->expectDeprecation('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445');
+    // We purposely test accessing an undefined property here. We need to tell
+    // PHPStan to ignore that.
+    // @phpstan-ignore-next-line
+    $this->assertInstanceOf(Random::class, $this->randomGenerator);
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/BrowserTestBase.php b/core/tests/Drupal/Tests/BrowserTestBase.php
index afc09febcacb3c1625224032087e45ade0bacbba..3d3e41c51d945c9d6e134ef7d504088115be23bc 100644
--- a/core/tests/Drupal/Tests/BrowserTestBase.php
+++ b/core/tests/Drupal/Tests/BrowserTestBase.php
@@ -19,7 +19,6 @@
 use Drupal\Tests\Traits\PhpUnitWarnings;
 use Drupal\Tests\user\Traits\UserCreationTrait;
 use Drupal\TestTools\Comparator\MarkupInterfaceComparator;
-use Drupal\TestTools\Random;
 use Drupal\TestTools\TestVarDumper;
 use GuzzleHttp\Cookie\CookieJar;
 use PHPUnit\Framework\TestCase;
@@ -383,7 +382,9 @@ protected function setUp(): void {
    */
   public function __get(string $name) {
     if ($name === 'randomGenerator') {
-      return Random::getGenerator();
+      @trigger_error('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445', E_USER_DEPRECATED);
+
+      return $this->getRandomGenerator();
     }
   }
 
diff --git a/core/tests/Drupal/Tests/Core/Test/BrowserTestBaseTest.php b/core/tests/Drupal/Tests/Core/Test/BrowserTestBaseTest.php
index b32a8b396f894768d05b7942c031349141a22e0c..1463b4b075b760cd94507210771036ea83176a7d 100644
--- a/core/tests/Drupal/Tests/Core/Test/BrowserTestBaseTest.php
+++ b/core/tests/Drupal/Tests/Core/Test/BrowserTestBaseTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Core\Test;
 
+use Drupal\Component\Utility\Random;
 use Drupal\Tests\DrupalTestBrowser;
 use Drupal\Tests\UnitTestCase;
 use Drupal\Tests\BrowserTestBase;
@@ -92,4 +93,17 @@ public function testTearDownWithoutSetUp() {
     $ref_tearDown->invoke($btb);
   }
 
+  /**
+   * Tests the deprecation of accessing the randomGenerator property directly.
+   *
+   * @group legacy
+   */
+  public function testGetRandomGeneratorPropertyDeprecation() {
+    $this->expectDeprecation('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445');
+    // We purposely test accessing an undefined property here. We need to tell
+    // PHPStan to ignore that.
+    // @phpstan-ignore-next-line
+    $this->assertInstanceOf(Random::class, $this->randomGenerator);
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/UnitTestCase.php b/core/tests/Drupal/Tests/UnitTestCase.php
index d47eef9373d0a7e6cd8cc69962848af0c84a4426..0e1773deac4758bb1bb3b597058403bf5d19dfb1 100644
--- a/core/tests/Drupal/Tests/UnitTestCase.php
+++ b/core/tests/Drupal/Tests/UnitTestCase.php
@@ -9,7 +9,6 @@
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\StringTranslation\PluralTranslatableMarkup;
 use Drupal\Tests\Traits\PhpUnitWarnings;
-use Drupal\TestTools\Random;
 use Drupal\TestTools\TestVarDumper;
 use PHPUnit\Framework\TestCase;
 use Prophecy\PhpUnit\ProphecyTrait;
@@ -70,7 +69,9 @@ protected function setUp(): void {
    */
   public function __get(string $name) {
     if ($name === 'randomGenerator') {
-      return Random::getGenerator();
+      @trigger_error('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445', E_USER_DEPRECATED);
+
+      return $this->getRandomGenerator();
     }
   }
 
diff --git a/core/tests/Drupal/Tests/UnitTestCaseTest.php b/core/tests/Drupal/Tests/UnitTestCaseTest.php
index b5fd12cde8833ccb5d58ffaa964b0a2773903aaf..375d2e5dba1cfa9e45bf5467a17df2b6b80b334f 100644
--- a/core/tests/Drupal/Tests/UnitTestCaseTest.php
+++ b/core/tests/Drupal/Tests/UnitTestCaseTest.php
@@ -2,6 +2,8 @@
 
 namespace Drupal\Tests;
 
+use Drupal\Component\Utility\Random;
+
 /**
  * Tests for the UnitTestCase class.
  *
@@ -53,4 +55,17 @@ public function testVarDumpSeparateProcess() {
     $this->assertStringContainsString('banana', StreamCapturer::$cache);
   }
 
+  /**
+   * Tests the deprecation of accessing the randomGenerator property directly.
+   *
+   * @group legacy
+   */
+  public function testGetRandomGeneratorPropertyDeprecation() {
+    $this->expectDeprecation('Accessing the randomGenerator property is deprecated in drupal:10.2.0 and is removed from drupal:11.0.0. Use getRandomGenerator() instead. See https://www.drupal.org/node/3358445');
+    // We purposely test accessing an undefined property here. We need to tell
+    // PHPStan to ignore that.
+    // @phpstan-ignore-next-line
+    $this->assertInstanceOf(Random::class, $this->randomGenerator);
+  }
+
 }