diff --git a/core/modules/system/src/Tests/Theme/ThemeTest.php b/core/modules/system/src/Tests/Theme/ThemeTest.php
index d8f2c89..80d21d5 100644
--- a/core/modules/system/src/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/src/Tests/Theme/ThemeTest.php
@@ -282,7 +282,7 @@ function testPreprocessHtml() {
    * Tests that region attributes can be manipulated via preprocess functions.
    */
   function testRegionClass() {
-    \Drupal::moduleHandler()->install(array('system', 'block', 'theme_region_test'));
+    \Drupal::moduleHandler()->install(array('block', 'theme_region_test'));
 
     // Place a block.
     $this->drupalPlaceBlock('system_main_block');