diff --git a/core/tests/Drupal/Tests/Core/PhpStorage/CacheStorageTest.php b/core/tests/Drupal/Tests/Core/PhpStorage/CacheStorageTest.php
index ff1caed..26a5adf 100644
--- a/core/tests/Drupal/Tests/Core/PhpStorage/CacheStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/PhpStorage/CacheStorageTest.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\Tests\Core\PhpStorage;
 
-use Drupal\Component\PhpStorage\PhpStorageInterface;
 use Drupal\Core\Cache\MemoryBackend;
 use Drupal\Core\PhpStorage\CacheStorage;
 use Drupal\Tests\Component\PhpStorage\PhpStorageTestBase;
@@ -20,6 +19,13 @@
 class CacheStorageTest extends PhpStorageTestBase {
 
   /**
+   * The contents of the cache backend.
+   *
+   * @var array
+   */
+  protected $cache;
+
+  /**
    * Tests basic load/save/delete operations.
    *
    * @covers ::load
@@ -39,16 +45,40 @@ public function testCRUD() {
     $this->assertCRUD($storage);
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  protected function additionalAssertCRUD(PhpStorageInterface $php, $name) {
-    $this->assertTrue(isset(opcache_get_status(TRUE)['scripts']["phar://$name"]['hits']));
-    if (ini_get('opcache.enable_cli')) {
-      $this->assertEquals(opcache_get_status(TRUE)['scripts']["phar://$name"]['hits'], 0);
-      $php->load($name);
-      $this->assertEquals(opcache_get_status(TRUE)['scripts']["phar://$name"]['hits'], 1);
-    }
+  public function testCache() {
+    $cache_backend = $this->getMock('Drupal\Core\Cache\CacheBackendInterface');
+    $cache_backend->expects($this->once())
+      ->method('setMultiple')
+      ->willReturnCallback(function ($data) {
+          $this->cache = $data;
+    });
+    // mtime wil be retrieved on both loads. If opcache.enable_cli is on then
+    // the file itself is loaded only once.
+    $cache_backend->expects($this->exactly(4 - ini_get('opcache.enable_cli')))
+      ->method('get')
+      ->willReturnCallback(function ($cid) {
+        return (object) $this->cache[$cid];
+      });
+    $secret = $this->randomMachineName();
+    $storage = new CacheStorage([
+      'secret' => $secret,
+      'cache_backend_factory' => function () use ($cache_backend) {
+        return $cache_backend;
+      },
+      'bin' => 'test'
+    ]);
+    $name = $this->randomMachineName() . '/' . $this->randomMachineName() . '.php';
+
+    // Find a global that doesn't exist.
+    do {
+      $random = mt_rand(10000, 100000);
+    } while (isset($GLOBALS[$random]));
+
+    // Write out a PHP file and ensure it's successfully loaded.
+    $code = "<?php\n\$GLOBALS[$random] = TRUE;";
+    $storage->save($name, $code);
+    $storage->load($name);
+    $storage->load($name);
   }
 
 }