.../language/lib/Drupal/language/Tests/LanguageSwitchingTest.php     |    2 +-
 core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php      |    2 +-
 .../modules/theme_test/templates/theme-test-render-element.html.twig |    1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
index 266580f..c02db32 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
@@ -60,7 +60,7 @@ function testLanguageBlock() {
     $this->assertText($block->label(), 'Language switcher block found.');
 
     // Assert that only the current language is marked as active.
-    list($language_switcher) = $this->xpath('//div[@id=:id]/div[@class="language-switcher-language-url content"]', array(':id' => 'block-test-language-block'));
+    list($language_switcher) = $this->xpath('//div[@id=:id]/div[contains(@class, "content")]', array(':id' => 'block-test-language-block'));
     $links = array(
       'active' => array(),
       'inactive' => array(),
diff --git a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
index 7f5c2d2..55be322 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
@@ -54,7 +54,7 @@ function testAttributeMerging() {
         'id' => 'bazinga',
       ),
     ));
-    $this->assertIdentical($output, '<div id="bazinga" data-foo="bar" class="theme-test-render-element" data-variables-are-preprocessed></div>' . "\n");
+    $this->assertIdentical($output, '<div id="bazinga" data-foo="bar" data-variables-are-preprocessed></div>' . "\n");
   }
 
   /**
diff --git a/core/modules/system/tests/modules/theme_test/templates/theme-test-render-element.html.twig b/core/modules/system/tests/modules/theme_test/templates/theme-test-render-element.html.twig
new file mode 100644
index 0000000..338d9f2
--- /dev/null
+++ b/core/modules/system/tests/modules/theme_test/templates/theme-test-render-element.html.twig
@@ -0,0 +1 @@
+<div{{ attributes }}></div>