diff --git a/core/lib/Drupal/Core/Cache/MemoryBackendFactory.php b/core/lib/Drupal/Core/Cache/MemoryBackendFactory.php
new file mode 100644
index 0000000..6a9b132
--- /dev/null
+++ b/core/lib/Drupal/Core/Cache/MemoryBackendFactory.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\Core\Cache\MemoryBackendFactory.
+ */
+
+namespace Drupal\Core\Cache;
+
+/**
+ * Defines a factory for the cache memory backend.
+ */
+class MemoryBackendFactory {
+
+  /**
+   * Constructs a new cache database backend for a given bin name.
+   *
+   * @param string $bin
+   *   The cache bin for which a cache backend object should be returned.
+   *
+   * @return Drupal\Core\Cache\CacheBackendInterface
+   *   The cache backend object associated with the specified bin.
+   */
+  public function get($bin) {
+    return new MemoryBackend($bin);
+  }
+}
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index a21d496..bc0b3b4 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -82,7 +82,8 @@ protected function setUp() {
 
     // Provide a minimal, partially mocked environment for unit tests.
     $conf['lock_backend'] = 'Drupal\Core\Lock\NullLockBackend';
-    $conf['cache_classes'] = array('cache' => 'Drupal\Core\Cache\MemoryBackend');
+    $this->container->register('cache.memory', 'Drupal\Core\Cache\MemoryBackendFactory');
+    $conf['cache_bin'] = 'cache.memory';
     $this->container
       ->register('config.storage', 'Drupal\Core\Config\FileStorage')
       ->addArgument($this->configDirectories[CONFIG_ACTIVE_DIRECTORY]);
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index ebadf43..06a29f1 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -724,7 +724,7 @@ protected function setUp() {
     $batch = $this->originalBatch;
 
     // Revert install_begin_request() cache and lock service overrides.
-    unset($conf['cache_classes']);
+    unset($conf['cache.bin']);
     unset($conf['lock_backend']);
 
     // Set path variables.