diff --git a/core/modules/system/src/Tests/Asset/LibraryCompletenessTest.php b/core/modules/system/src/Tests/Asset/ResolvedLibraryDefinitionsFilesMatchTest.php
similarity index 92%
rename from core/modules/system/src/Tests/Asset/LibraryCompletenessTest.php
rename to core/modules/system/src/Tests/Asset/ResolvedLibraryDefinitionsFilesMatchTest.php
index 48a879b..57baf02 100644
--- a/core/modules/system/src/Tests/Asset/LibraryCompletenessTest.php
+++ b/core/modules/system/src/Tests/Asset/ResolvedLibraryDefinitionsFilesMatchTest.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\system\Tests\Asset\LibraryCompletenessTest.
+ * Contains \Drupal\system\Tests\Asset\ResolvedLibraryDefinitionsFilesMatchTest.
  */
 
 namespace Drupal\system\Tests\Asset;
@@ -10,11 +10,15 @@
 use Drupal\simpletest\KernelTestBase;
 
 /**
- * Tests that the files for all core libraries actually exist.
+ * Tests that the defined library files for all core extensions actually exist.
+ *
+ * This test also changes the active theme to each core theme to verify
+ * the libraries after theme-level libraries-override and libraries-extend are
+ * applied.
  *
  * @group Asset
  */
-class LibraryCompletenessTest extends KernelTestBase {
+class ResolvedLibraryDefinitionsFilesMatchTest extends KernelTestBase {
 
   /**
    * The theme handler.
@@ -111,7 +115,7 @@ public function testCoreLibraryCompleteness() {
     $this->verifyLibraryFilesExist($this->getAllLibraries());
 
     // Then verify all libraries for each core theme. This may seem like
-    // overkill but themes can override and extend other extension's libraries
+    // overkill but themes can override and extend other extensions' libraries
     // and these changes are only applied for the active theme.
     foreach ($this->allThemes as $theme) {
       $this->themeManager->setActiveTheme($this->themeInitialization->getActiveThemeByName($theme));