diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
index 1a0fd00206f..bc80fd8ddbb 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
@@ -9,6 +9,7 @@ namespace Drupal\block\Tests;
 
 use Drupal\Core\Cache\Cache;
 use Drupal\simpletest\WebTestBase;
+use Drupal\Component\Utility\String;
 
 /**
  * Provides testing for basic block module functionality.
@@ -185,20 +186,16 @@ class BlockTest extends BlockTestBase {
    * Test block display of theme titles.
    */
   function testThemeName() {
-    \Drupal::moduleHandler()->install(array('block_test'));
+    // Enable the help block.
+    $this->drupalPlaceBlock('system_help_block', array('region' => 'help'));
     // Explicitly set the default and admin themes.
-    $theme = 'cat_mouse';
-    theme_enable(array($theme, 'seven', 'block_test_theme'));
-    $this->resetAll();
-
-    \Drupal::config('system.theme')
-      ->set('default', 'seven')
-      ->set('admin', 'seven')
-      ->save();
+    $theme = 'block_test_specialchars_theme';
+    theme_enable(array($theme));
     \Drupal::service('router.builder')->rebuild();
-    $this->drupalGet('admin/appearance');
     $this->drupalGet('admin/structure/block');
-    $this->assertText('<"Cat" & 'Mouse'>');
+    $this->assertRaw(String::checkPlain('<"Cat" & \'Mouse\'>'));
+    $this->drupalGet('admin/structure/block/list/block_test_specialchars_theme');
+    $this->assertRaw(String::checkPlain('Demonstrate block regions (<"Cat" & \'Mouse\'>)'));
   }
 
   /**
diff --git a/core/modules/block/tests/modules/block_test/block_test.module b/core/modules/block/tests/modules/block_test/block_test.module
index 726043c17bf..a527ae1ddee 100644
--- a/core/modules/block/tests/modules/block_test/block_test.module
+++ b/core/modules/block/tests/modules/block_test/block_test.module
@@ -7,15 +7,6 @@
 
 use Drupal\block\BlockPluginInterface;
 
-/**
- * Implements hook_system_theme_info().
- */
-function block_test_system_theme_info() {
-  $themes['block_test_theme'] = drupal_get_path('module', 'block_test') . '/themes/block_test_theme/block_test_theme.info.yml';
-  $themes['cat_mouse'] = drupal_get_path('module', 'block_test') . '/themes/cat_mouse/cat_mouse.info.yml';
-  return $themes;
-}
-
 /**
  * Implements hook_block_alter().
  */
diff --git a/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml b/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml
new file mode 100644
index 00000000000..5b4689eddbc
--- /dev/null
+++ b/core/modules/block/tests/modules/block_test/themes/block_test_specialchars_theme/block_test_specialchars_theme.info.yml
@@ -0,0 +1,8 @@
+name: '<"Cat" & ''Mouse''>'
+type: theme
+description: 'Theme for testing special characters in block admin.'
+core: 8.x
+hidden: true
+regions:
+  content: Content
+  help: Help
diff --git a/core/modules/block/tests/modules/block_test/themes/cat_mouse/cat_mouse.info.yml b/core/modules/block/tests/modules/block_test/themes/cat_mouse/cat_mouse.info.yml
deleted file mode 100644
index 999f7f3b3ca..00000000000
--- a/core/modules/block/tests/modules/block_test/themes/cat_mouse/cat_mouse.info.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: '<"Cat" & ''Mouse''>'
-type: theme
-description: 'Theme for testing special characters in block admin.'
-core: 8.x
-hidden: true
-regions:
-  sidebar_first: 'Left sidebar'
-  sidebar_second: 'Right sidebar'
-  content: Content
-  header: Header
-  footer: Footer
-  highlighted: Highlighted
-  help: Help
-regions_hidden:
-  - sidebar_first
-  - sidebar_second