diff --git a/core/modules/system/src/Tests/Asset/LibraryDiscoveryIntegrationTest.php b/core/modules/system/src/Tests/Asset/LibraryDiscoveryIntegrationTest.php
index 59e3532..2886258 100644
--- a/core/modules/system/src/Tests/Asset/LibraryDiscoveryIntegrationTest.php
+++ b/core/modules/system/src/Tests/Asset/LibraryDiscoveryIntegrationTest.php
@@ -46,16 +46,16 @@ public function testElementInfoByTheme() {
    * Tests that libraries-override are applied to library definitions.
    */
   public function testLibrariesOverride() {
-    // Assert some classy libraries exist that we are going to override.
+    // Assert some classy libraries that will be overridden or removed.
     $this->activateTheme('classy');
     $this->assertAssetInLibrary('core/themes/classy/css/components/button.css', 'classy', 'base', 'css');
     $this->assertAssetInLibrary('core/themes/classy/css/components/collapse-processed.css', 'classy', 'base', 'css');
     $this->assertAssetInLibrary('core/themes/classy/css/components/container-inline.css', 'classy', 'base', 'css');
     $this->assertAssetInLibrary('core/themes/classy/css/components/details.css', 'classy', 'base', 'css');
+    $this->assertAssetInLibrary('core/themes/classy/css/components/dialog.css', 'classy', 'dialog', 'css');
 
-    // Confirmatory asserts on other libraries to be removed or overridden.
+    // Confirmatory assert on core library to be removed.
     $this->assertTrue($this->libraryDiscovery->getLibraryByName('core', 'drupal.progress'), 'Confirmatory test on "core/drupal.progress"');
-    $this->assertAssetInLibrary('core/misc/dialog.theme.css', 'core', 'drupal.dialog', 'css');
 
     // Activate test theme that defines libraries overrides.
     $this->activateTheme('test_theme');
@@ -63,11 +63,12 @@ public function testLibrariesOverride() {
     // Assert that entire library was correctly overridden.
     $this->assertEqual($this->libraryDiscovery->getLibraryByName('core', 'drupal.collapse'), $this->libraryDiscovery->getLibraryByName('test_theme', 'collapse'), 'Entire library correctly overridden.');
 
-    // Assert that classy library assets were correctly overridden.
+    // Assert that classy library assets were correctly overridden or removed.
     $this->assertNoAssetInLibrary('core/themes/classy/css/components/button.css', 'classy', 'base', 'css');
     $this->assertNoAssetInLibrary('core/themes/classy/css/components/collapse-processed.css', 'classy', 'base', 'css');
     $this->assertNoAssetInLibrary('core/themes/classy/css/components/container-inline.css', 'classy', 'base', 'css');
     $this->assertNoAssetInLibrary('core/themes/classy/css/components/details.css', 'classy', 'base', 'css');
+    $this->assertNoAssetInLibrary('core/themes/classy/css/components/dialog.css', 'classy', 'dialog', 'css');
 
     $this->assertAssetInLibrary('core/modules/system/tests/themes/test_theme/css/my-button.css', 'classy', 'base', 'css');
     $this->assertAssetInLibrary('core/modules/system/tests/themes/test_theme/css/my-collapse-processed.css', 'classy', 'base', 'css');
@@ -77,9 +78,6 @@ public function testLibrariesOverride() {
     // Assert that entire library was correctly removed.
     $this->assertFalse($this->libraryDiscovery->getLibraryByName('core', 'drupal.progress'), 'Entire library correctly removed.');
 
-    // Assert that library asset was correctly removed.
-    $this->assertNoAssetInLibrary('core/misc/dialog.theme.css', 'core', 'drupal.dialog', 'css');
-
     // Assert that overridden library asset still retains attributes.
     $library = $this->libraryDiscovery->getLibraryByName('core', 'jquery');
     foreach ($library['js'] as $definition) {
diff --git a/core/modules/system/tests/themes/test_theme/test_theme.info.yml b/core/modules/system/tests/themes/test_theme/test_theme.info.yml
index d872e33..4c1568c 100644
--- a/core/modules/system/tests/themes/test_theme/test_theme.info.yml
+++ b/core/modules/system/tests/themes/test_theme/test_theme.info.yml
@@ -32,10 +32,10 @@ libraries-override:
         css/components/container-inline.css: /themes/my_theme/css/my-container-inline.css
         css/components/details.css: /themes/my_theme/css/my-details.css
   # Remove particular library assets.
-  core/drupal.dialog:
+  classy/dialog:
     css:
-      theme:
-        misc/dialog.theme.css: false
+      component:
+        css/components/dialog.css: false
   # It works for JS as well.
   core/jquery:
     js: