diff --git a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
index 0bc52d0..f818637 100644
--- a/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigEnvironmentTest.php
@@ -120,13 +120,18 @@ public function testCacheFilename() {
     // Note: Later we refetch the twig service in order to bypass its internal
     // static cache.
     $environment = \Drupal::service('twig');
+    $template_path = 'core/modules/system/templates/container.html.twig';
 
-    $original_filename = $environment->getCacheFilename('core/modules/system/templates/container.html.twig');
+    $cache = $environment->getCache();
+    $class = $environment->getTemplateClass($template_path);
+    $original_filename = $cache->generateKey($template_path, $class);
     \Drupal::getContainer()->set('twig', NULL);
 
     \Drupal::service('module_installer')->install(['twig_extension_test']);
     $environment = \Drupal::service('twig');
-    $new_extension_filename = $environment->getCacheFilename('core/modules/system/templates/container.html.twig');
+    $cache = $environment->getCache();
+    $class = $environment->getTemplateClass($template_path);
+    $new_extension_filename = $cache->generateKey($template_path, $class);
     \Drupal::getContainer()->set('twig', NULL);
 
     $this->assertNotEqual($new_extension_filename, $original_filename);
diff --git a/core/modules/system/src/Tests/Theme/TwigSettingsTest.php b/core/modules/system/src/Tests/Theme/TwigSettingsTest.php
index f581fa62..74a517b 100644
--- a/core/modules/system/src/Tests/Theme/TwigSettingsTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigSettingsTest.php
@@ -101,7 +101,11 @@ function testTwigCacheOverride() {
     // theme_test.template_test.html.twig.
     $info = $templates->get('theme_test_template_test');
     $template_filename = $info['path'] . '/' . $info['template'] . $extension;
-    $cache_filename = $this->container->get('twig')->getCacheFilename($template_filename);
+
+    $environment = $this->container->get('twig');
+    $cache = $environment->getCache();
+    $class = $environment->getTemplateClass($template_filename);
+    $cache_filename = $cache->generateKey($template_filename, $class);
 
     // Navigate to the page and make sure the template gets cached.
     $this->drupalGet('theme-test/template-test');
diff --git a/core/modules/system/tests/modules/twig_extension_test/src/TwigExtension/TestExtension.php b/core/modules/system/tests/modules/twig_extension_test/src/TwigExtension/TestExtension.php
index 3c2b851..c4c6025 100644
--- a/core/modules/system/tests/modules/twig_extension_test/src/TwigExtension/TestExtension.php
+++ b/core/modules/system/tests/modules/twig_extension_test/src/TwigExtension/TestExtension.php
@@ -12,7 +12,7 @@
 /**
  * A test Twig extension that adds a custom function and a custom filter.
  */
-class TestExtension extends TwigExtension {
+class TestExtension extends \Twig_Extension {
 
   /**
    * Generates a list of all Twig functions that this extension defines.
@@ -27,9 +27,9 @@ class TestExtension extends TwigExtension {
    *   The value is a standard PHP callback that defines what the function does.
    */
   public function getFunctions() {
-    return array(
-      'testfunc' => new \Twig_Function_Function(array('Drupal\twig_extension_test\TwigExtension\TestExtension', 'testFunction')),
-    );
+    return [
+      new \Twig_SimpleFunction('testfunc', [$this, 'testFunction']),
+    ];
   }
 
   /**
@@ -45,9 +45,9 @@ public function getFunctions() {
    *   The value is a standard PHP callback that defines what the filter does.
    */
   public function getFilters() {
-    return array(
-      'testfilter' => new \Twig_Filter_Function(array('Drupal\twig_extension_test\TwigExtension\TestExtension', 'testFilter')),
-    );
+    return [
+      new \Twig_SimpleFilter('testfilter', [$this, 'testFilter']),
+    ];
   }
 
   /**
diff --git a/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.services.yml b/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.services.yml
index 491d1e8..8784c0f 100644
--- a/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.services.yml
+++ b/core/modules/system/tests/modules/twig_extension_test/twig_extension_test.services.yml
@@ -1,6 +1,5 @@
 services:
   twig_extension_test.twig.test_extension:
-    arguments: ['@renderer']
     class: Drupal\twig_extension_test\TwigExtension\TestExtension
     tags:
       - { name: twig.extension }
diff --git a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
index 69941a9..3f7a5f1 100644
--- a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
+++ b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
@@ -12,6 +12,7 @@
 use Drupal\Core\Template\Attribute;
 use Drupal\Core\Template\AttributeArray;
 use Drupal\Core\Template\AttributeString;
+use Drupal\Core\Template\Loader\StringLoader;
 use Drupal\Tests\UnitTestCase;
 use Drupal\Component\Render\MarkupInterface;
 
@@ -268,7 +269,7 @@ public function testChainAddRemoveClasses() {
    * @covers ::addClass
    */
   public function testTwigAddRemoveClasses($template, $expected, $seed_attributes = array()) {
-    $loader = new \Twig_Loader_String();
+    $loader = new StringLoader();
     $twig = new \Twig_Environment($loader);
     $data = array('attributes' => new Attribute($seed_attributes));
     $result = $twig->render($template, $data);
diff --git a/core/tests/Drupal/Tests/Core/Template/TwigExtensionTest.php b/core/tests/Drupal/Tests/Core/Template/TwigExtensionTest.php
index 6b9525e..bb3f4c4 100644
--- a/core/tests/Drupal/Tests/Core/Template/TwigExtensionTest.php
+++ b/core/tests/Drupal/Tests/Core/Template/TwigExtensionTest.php
@@ -5,7 +5,7 @@
  * Contains \Drupal\Tests\Core\Template\TwigExtensionTest.
  */
 
-namespace Drupal\Tests\Core\Template;
+namespace Drupal\Tests\Core\Template {
 
 use Drupal\Core\Render\RenderableInterface;
 use Drupal\Core\Render\RendererInterface;
@@ -31,7 +31,8 @@ class TwigExtensionTest extends UnitTestCase {
    */
   public function testEscaping($template, $expected) {
     $renderer = $this->getMock('\Drupal\Core\Render\RendererInterface');
-    $twig = new \Twig_Environment(NULL, array(
+    $loader = new \Twig_Loader_Filesystem();
+    $twig = new \Twig_Environment($loader, array(
       'debug' => TRUE,
       'cache' => FALSE,
       'autoescape' => 'html',
@@ -97,7 +98,7 @@ public function testActiveTheme() {
       ->willReturn($active_theme);
     $extension->setThemeManager($theme_manager);
 
-    $loader = new \Twig_Loader_String();
+    $loader = new StringLoader();
     $twig = new \Twig_Environment($loader);
     $twig->addExtension($extension);
     $result = $twig->render('{{ active_theme() }}');
@@ -145,7 +146,7 @@ public function testActiveThemePath() {
       ->willReturn($active_theme);
     $extension->setThemeManager($theme_manager);
 
-    $loader = new \Twig_Loader_String();
+    $loader = new StringLoader();
     $twig = new \Twig_Environment($loader);
     $twig->addExtension($extension);
     $result = $twig->render('{{ active_theme_path() }}');
@@ -159,7 +160,8 @@ public function testActiveThemePath() {
    */
   public function testSafeStringEscaping() {
     $renderer = $this->getMock('\Drupal\Core\Render\RendererInterface');
-    $twig = new \Twig_Environment(NULL, array(
+    $loader = new \Twig_Loader_Filesystem();
+    $twig = new \Twig_Environment($loader, array(
       'debug' => TRUE,
       'cache' => FALSE,
       'autoescape' => 'html',
@@ -241,3 +243,16 @@ public function __toString() {
   }
 
 }
+
+}
+
+namespace {
+  if (!function_exists('t')) {
+    function t($string, array $args = []) {
+      return strtr($string, $args);
+    }
+  }
+  if (!function_exists('file_create_url')) {
+    function file_create_url() {}
+  }
+}