diff --git a/core/modules/system/src/Tests/Update/PathAliasUpdateTest.php b/core/modules/system/src/Tests/Update/PathAliasUpdateTest.php
index 3da9741..2d84a59 100644
--- a/core/modules/system/src/Tests/Update/PathAliasUpdateTest.php
+++ b/core/modules/system/src/Tests/Update/PathAliasUpdateTest.php
@@ -35,22 +35,134 @@ public function testUpdate() {
     if (!$schema->tableExists('url_alias')) {
       return;
     }
-    $this->runUpdates();
-
-    // A copy of the data from drupal-8.path-alias-lowercase-2075889.php
-    $data = [
-      '/node/add' => '/Content/CREATE',
-      '/admin/config/search/path/filter' => '/ADMIN/config/FIND/paths',
-      '/search/user/help' => '/SEARCH/people/HELP',
-    ];
     /** @var \Drupal\Core\Path\AliasStorageInterface $alias_storage */
     $alias_storage = \Drupal::service('path.alias_storage');
 
+    // Check that the aliases are mixed case before updating.
+    foreach ($this-> aliasData() as $source => $path) {
+      $alias = $alias_storage->load(['source' => $source]);
+      $this->assertIdentical($path, $alias['alias']);
+    }
+
+    $this->runUpdates();
+
     // Check that the mixed case path aliases were converted to all lower case.
-    foreach ($data as $source => $path) {
+    foreach ($this-> aliasData() as $source => $path) {
       $alias = $alias_storage->load(['source' => $source]);
       $this->assertIdentical(Unicode::strtolower($path), $alias['alias']);
     }
   }
 
+  /**
+   * Returns a copy of the data from drupal-8.path-alias-lowercase-2075889.php
+   *
+   * @return array
+   *   Keys are route paths and values are aliases.
+   */
+  public function  aliasData() {
+    return [
+      '/node/add' => '/Content/CREATE',
+      '/admin/config/search/path/filter' => '/ADMIN/config/FIND/paths',
+      '/admin/reports/fields' => '/ALIASprefix/admin/reports/fields',
+      '/admin/config/media/image-styles' => '/ALIASprefix/admin/config/media/image-styles',
+      '/admin/structure/menu/add' => '/ALIASprefix/admin/structure/menu/add',
+      '/admin/structure/menu' => '/ALIASprefix/admin/structure/menu',
+      '/admin/structure/types' => '/ALIASprefix/admin/structure/types',
+      '/admin/config/search/pages' => '/ALIASprefix/admin/config/search/pages',
+      '/admin/config/user-interface/shortcut' => '/ALIASprefix/admin/config/user-interface/shortcut',
+      '/admin/structure/taxonomy/add' => '/ALIASprefix/admin/structure/taxonomy/add',
+      '/admin/structure/taxonomy' => '/ALIASprefix/admin/structure/taxonomy',
+      '/admin/config/people/accounts' => '/ALIASprefix/admin/config/people/accounts',
+      '/admin/people' => '/ALIASprefix/admin/people',
+      '/admin/config/people/accounts/fields' => '/ALIASprefix/admin/config/people/accounts/fields',
+      '/admin/people/roles' => '/ALIASprefix/admin/people/roles',
+      '/admin/structure/views' => '/ALIASprefix/admin/structure/views',
+      '/admin/structure/display-modes' => '/ALIASprefix/admin/structure/display-modes',
+      '/admin/structure/display-modes/form/add' => '/ALIASprefix/admin/structure/display-modes/form/add',
+      '/admin/structure/display-modes/view/add' => '/ALIASprefix/admin/structure/display-modes/view/add',
+      '/admin/config/people/accounts/fields/add-field' => '/ALIASprefix/admin/config/people/accounts/fields/add-field',
+      '/file/progress' => '/ALIASprefix/file/progress',
+      '/admin/config/content/formats' => '/ALIASprefix/admin/config/content/formats',
+      '/admin/config/content/formats/add' => '/ALIASprefix/admin/config/content/formats/add',
+      '/filter/tips' => '/ALIASprefix/filter/tips',
+      '/admin/help' => '/ALIASprefix/admin/help',
+      '/history/get_node_read_timestamps' => '/ALIASprefix/history/get_node_read_timestamps',
+      '/admin/config/media/image-styles/add' => '/ALIASprefix/admin/config/media/image-styles/add',
+      '/admin/structure/menu/parents' => '/ALIASprefix/admin/structure/menu/parents',
+      '/admin/reports/status/rebuild' => '/ALIASprefix/admin/reports/status/rebuild',
+      '/admin/content/node/delete' => '/ALIASprefix/admin/content/node/delete',
+      '/admin/structure/types/add' => '/ALIASprefix/admin/structure/types/add',
+      '/admin/config/search/path/add' => '/ALIASprefix/admin/config/search/path/add',
+      '/admin/config/search/path' => '/ALIASprefix/admin/config/search/path',
+      '/quickedit/attachments' => '/ALIASprefix/quickedit/attachments',
+      '/quickedit/metadata' => '/ALIASprefix/quickedit/metadata',
+      '/search/node/help' => '/ALIASprefix/search/node/help',
+      '/admin/config/search/pages/reindex' => '/ALIASprefix/admin/config/search/pages/reindex',
+      '/search' => '/ALIASprefix/search',
+      '/search/node' => '/ALIASprefix/search/node',
+      '/search/user' => '/ALIASprefix/search/user',
+      '/admin/config/user-interface/shortcut/add-set' => '/ALIASprefix/admin/config/user-interface/shortcut/add-set',
+      '/admin' => '/ALIASprefix/admin',
+      '/admin/config' => '/ALIASprefix/admin/config',
+      '/admin/config/content' => '/ALIASprefix/admin/config/content',
+      '/admin/config/development' => '/ALIASprefix/admin/config/development',
+      '/admin/config/media' => '/ALIASprefix/admin/config/media',
+      '/admin/config/regional' => '/ALIASprefix/admin/config/regional',
+      '/admin/config/search' => '/ALIASprefix/admin/config/search',
+      '/admin/config/services' => '/ALIASprefix/admin/config/services',
+      '/admin/config/system' => '/ALIASprefix/admin/config/system',
+      '/admin/config/user-interface' => '/ALIASprefix/admin/config/user-interface',
+      '/admin/config/workflow' => '/ALIASprefix/admin/config/workflow',
+      '/admin/content' => '/ALIASprefix/admin/content',
+      '/admin/index' => '/ALIASprefix/admin/index',
+      '/admin/reports' => '/ALIASprefix/admin/reports',
+      '/admin/structure' => '/ALIASprefix/admin/structure',
+      '/admin/config/system/cron' => '/ALIASprefix/admin/config/system/cron',
+      '/admin/config/regional/date-time/formats/add' => '/ALIASprefix/admin/config/regional/date-time/formats/add',
+      '/admin/config/media/file-system' => '/ALIASprefix/admin/config/media/file-system',
+      '/admin/config/media/image-toolkit' => '/ALIASprefix/admin/config/media/image-toolkit',
+      '/admin/config/development/logging' => '/ALIASprefix/admin/config/development/logging',
+      '/machine_name/transliterate' => '/ALIASprefix/machine_name/transliterate',
+      '/admin/modules' => '/ALIASprefix/admin/modules',
+      '/admin/modules/list/confirm' => '/ALIASprefix/admin/modules/list/confirm',
+      '/admin/modules/uninstall' => '/ALIASprefix/admin/modules/uninstall',
+      '/admin/modules/uninstall/confirm' => '/ALIASprefix/admin/modules/uninstall/confirm',
+      '/admin/config/development/performance' => '/ALIASprefix/admin/config/development/performance',
+      '/admin/reports/status/php' => '/ALIASprefix/admin/reports/status/php',
+      '/admin/config/regional/settings' => '/ALIASprefix/admin/config/regional/settings',
+      '/admin/config/services/rss-publishing' => '/ALIASprefix/admin/config/services/rss-publishing',
+      '/admin/reports/status/run-cron' => '/ALIASprefix/admin/reports/status/run-cron',
+      '/admin/config/system/site-information' => '/ALIASprefix/admin/config/system/site-information',
+      '/admin/config/development/maintenance' => '/ALIASprefix/admin/config/development/maintenance',
+      '/admin/reports/status' => '/ALIASprefix/admin/reports/status',
+      '/system/temporary' => '/ALIASprefix/system/temporary',
+      '/admin/appearance' => '/ALIASprefix/admin/appearance',
+      '/admin/appearance/install' => '/ALIASprefix/admin/appearance/install',
+      '/admin/appearance/settings' => '/ALIASprefix/admin/appearance/settings',
+      '/admin/appearance/default' => '/ALIASprefix/admin/appearance/default',
+      '/admin/appearance/uninstall' => '/ALIASprefix/admin/appearance/uninstall',
+      '/admin/people/create' => '/ALIASprefix/admin/people/create',
+      '/admin/config/people' => '/ALIASprefix/admin/config/people',
+      '/admin/people/permissions' => '/ALIASprefix/admin/people/permissions',
+      '/user/login' => '/ALIASprefix/user/login',
+      '/user/logout' => '/ALIASprefix/user/logout',
+      '/admin/people/cancel' => '/ALIASprefix/admin/people/cancel',
+      '/user' => '/ALIASprefix/user',
+      '/user/password' => '/ALIASprefix/user/password',
+      '/user/register' => '/ALIASprefix/user/register',
+      '/admin/people/roles/add' => '/ALIASprefix/admin/people/roles/add',
+      '/admin/structure/block/block-content' => '/ALIASprefix/admin/structure/block/block-content',
+      '/admin/content/files' => '/ALIASprefix/admin/content/files',
+      '/rss.xml' => '/ALIASprefix/rss.xml',
+      '/node' => '/ALIASprefix/node',
+      '/admin/structure/views/add' => '/ALIASprefix/admin/structure/views/add',
+      '/admin/views/ajax/autocomplete/tag' => '/ALIASprefix/admin/views/ajax/autocomplete/tag',
+      '/admin/reports/fields/views-fields' => '/ALIASprefix/admin/reports/fields/views-fields',
+      '/admin/reports/views-plugins' => '/ALIASprefix/admin/reports/views-plugins',
+      '/admin/structure/views/settings/advanced' => '/ALIASprefix/admin/structure/views/settings/advanced',
+      '/admin/structure/views/settings' => '/ALIASprefix/admin/structure/views/settings',
+      '/search/user/help' => '/SEARCH/people/HELP',
+    ];
+  }
+
 }
diff --git a/core/modules/system/tests/fixtures/update/drupal-8.path-alias-lowercase-2075889.php b/core/modules/system/tests/fixtures/update/drupal-8.path-alias-lowercase-2075889.php
index b53279d..4f6f8a2 100644
--- a/core/modules/system/tests/fixtures/update/drupal-8.path-alias-lowercase-2075889.php
+++ b/core/modules/system/tests/fixtures/update/drupal-8.path-alias-lowercase-2075889.php
@@ -14,6 +14,104 @@
 $data = [
   '/node/add' => '/Content/CREATE',
   '/admin/config/search/path/filter' => '/ADMIN/config/FIND/paths',
+  '/admin/reports/fields' => '/ALIASprefix/admin/reports/fields',
+  '/admin/config/media/image-styles' => '/ALIASprefix/admin/config/media/image-styles',
+  '/admin/structure/menu/add' => '/ALIASprefix/admin/structure/menu/add',
+  '/admin/structure/menu' => '/ALIASprefix/admin/structure/menu',
+  '/admin/structure/types' => '/ALIASprefix/admin/structure/types',
+  '/admin/config/search/pages' => '/ALIASprefix/admin/config/search/pages',
+  '/admin/config/user-interface/shortcut' => '/ALIASprefix/admin/config/user-interface/shortcut',
+  '/admin/structure/taxonomy/add' => '/ALIASprefix/admin/structure/taxonomy/add',
+  '/admin/structure/taxonomy' => '/ALIASprefix/admin/structure/taxonomy',
+  '/admin/config/people/accounts' => '/ALIASprefix/admin/config/people/accounts',
+  '/admin/people' => '/ALIASprefix/admin/people',
+  '/admin/config/people/accounts/fields' => '/ALIASprefix/admin/config/people/accounts/fields',
+  '/admin/people/roles' => '/ALIASprefix/admin/people/roles',
+  '/admin/structure/views' => '/ALIASprefix/admin/structure/views',
+  '/admin/structure/display-modes' => '/ALIASprefix/admin/structure/display-modes',
+  '/admin/structure/display-modes/form/add' => '/ALIASprefix/admin/structure/display-modes/form/add',
+  '/admin/structure/display-modes/view/add' => '/ALIASprefix/admin/structure/display-modes/view/add',
+  '/admin/config/people/accounts/fields/add-field' => '/ALIASprefix/admin/config/people/accounts/fields/add-field',
+  '/file/progress' => '/ALIASprefix/file/progress',
+  '/admin/config/content/formats' => '/ALIASprefix/admin/config/content/formats',
+  '/admin/config/content/formats/add' => '/ALIASprefix/admin/config/content/formats/add',
+  '/filter/tips' => '/ALIASprefix/filter/tips',
+  '/admin/help' => '/ALIASprefix/admin/help',
+  '/history/get_node_read_timestamps' => '/ALIASprefix/history/get_node_read_timestamps',
+  '/admin/config/media/image-styles/add' => '/ALIASprefix/admin/config/media/image-styles/add',
+  '/admin/structure/menu/parents' => '/ALIASprefix/admin/structure/menu/parents',
+  '/admin/reports/status/rebuild' => '/ALIASprefix/admin/reports/status/rebuild',
+  '/admin/content/node/delete' => '/ALIASprefix/admin/content/node/delete',
+  '/admin/structure/types/add' => '/ALIASprefix/admin/structure/types/add',
+  '/admin/config/search/path/add' => '/ALIASprefix/admin/config/search/path/add',
+  '/admin/config/search/path' => '/ALIASprefix/admin/config/search/path',
+  '/quickedit/attachments' => '/ALIASprefix/quickedit/attachments',
+  '/quickedit/metadata' => '/ALIASprefix/quickedit/metadata',
+  '/search/node/help' => '/ALIASprefix/search/node/help',
+  '/admin/config/search/pages/reindex' => '/ALIASprefix/admin/config/search/pages/reindex',
+  '/search' => '/ALIASprefix/search',
+  '/search/node' => '/ALIASprefix/search/node',
+  '/search/user' => '/ALIASprefix/search/user',
+  '/admin/config/user-interface/shortcut/add-set' => '/ALIASprefix/admin/config/user-interface/shortcut/add-set',
+  '/admin' => '/ALIASprefix/admin',
+  '/admin/config' => '/ALIASprefix/admin/config',
+  '/admin/config/content' => '/ALIASprefix/admin/config/content',
+  '/admin/config/development' => '/ALIASprefix/admin/config/development',
+  '/admin/config/media' => '/ALIASprefix/admin/config/media',
+  '/admin/config/regional' => '/ALIASprefix/admin/config/regional',
+  '/admin/config/search' => '/ALIASprefix/admin/config/search',
+  '/admin/config/services' => '/ALIASprefix/admin/config/services',
+  '/admin/config/system' => '/ALIASprefix/admin/config/system',
+  '/admin/config/user-interface' => '/ALIASprefix/admin/config/user-interface',
+  '/admin/config/workflow' => '/ALIASprefix/admin/config/workflow',
+  '/admin/content' => '/ALIASprefix/admin/content',
+  '/admin/index' => '/ALIASprefix/admin/index',
+  '/admin/reports' => '/ALIASprefix/admin/reports',
+  '/admin/structure' => '/ALIASprefix/admin/structure',
+  '/admin/config/system/cron' => '/ALIASprefix/admin/config/system/cron',
+  '/admin/config/regional/date-time/formats/add' => '/ALIASprefix/admin/config/regional/date-time/formats/add',
+  '/admin/config/media/file-system' => '/ALIASprefix/admin/config/media/file-system',
+  '/admin/config/media/image-toolkit' => '/ALIASprefix/admin/config/media/image-toolkit',
+  '/admin/config/development/logging' => '/ALIASprefix/admin/config/development/logging',
+  '/machine_name/transliterate' => '/ALIASprefix/machine_name/transliterate',
+  '/admin/modules' => '/ALIASprefix/admin/modules',
+  '/admin/modules/list/confirm' => '/ALIASprefix/admin/modules/list/confirm',
+  '/admin/modules/uninstall' => '/ALIASprefix/admin/modules/uninstall',
+  '/admin/modules/uninstall/confirm' => '/ALIASprefix/admin/modules/uninstall/confirm',
+  '/admin/config/development/performance' => '/ALIASprefix/admin/config/development/performance',
+  '/admin/reports/status/php' => '/ALIASprefix/admin/reports/status/php',
+  '/admin/config/regional/settings' => '/ALIASprefix/admin/config/regional/settings',
+  '/admin/config/services/rss-publishing' => '/ALIASprefix/admin/config/services/rss-publishing',
+  '/admin/reports/status/run-cron' => '/ALIASprefix/admin/reports/status/run-cron',
+  '/admin/config/system/site-information' => '/ALIASprefix/admin/config/system/site-information',
+  '/admin/config/development/maintenance' => '/ALIASprefix/admin/config/development/maintenance',
+  '/admin/reports/status' => '/ALIASprefix/admin/reports/status',
+  '/system/temporary' => '/ALIASprefix/system/temporary',
+  '/admin/appearance' => '/ALIASprefix/admin/appearance',
+  '/admin/appearance/install' => '/ALIASprefix/admin/appearance/install',
+  '/admin/appearance/settings' => '/ALIASprefix/admin/appearance/settings',
+  '/admin/appearance/default' => '/ALIASprefix/admin/appearance/default',
+  '/admin/appearance/uninstall' => '/ALIASprefix/admin/appearance/uninstall',
+  '/admin/people/create' => '/ALIASprefix/admin/people/create',
+  '/admin/config/people' => '/ALIASprefix/admin/config/people',
+  '/admin/people/permissions' => '/ALIASprefix/admin/people/permissions',
+  '/user/login' => '/ALIASprefix/user/login',
+  '/user/logout' => '/ALIASprefix/user/logout',
+  '/admin/people/cancel' => '/ALIASprefix/admin/people/cancel',
+  '/user' => '/ALIASprefix/user',
+  '/user/password' => '/ALIASprefix/user/password',
+  '/user/register' => '/ALIASprefix/user/register',
+  '/admin/people/roles/add' => '/ALIASprefix/admin/people/roles/add',
+  '/admin/structure/block/block-content' => '/ALIASprefix/admin/structure/block/block-content',
+  '/admin/content/files' => '/ALIASprefix/admin/content/files',
+  '/rss.xml' => '/ALIASprefix/rss.xml',
+  '/node' => '/ALIASprefix/node',
+  '/admin/structure/views/add' => '/ALIASprefix/admin/structure/views/add',
+  '/admin/views/ajax/autocomplete/tag' => '/ALIASprefix/admin/views/ajax/autocomplete/tag',
+  '/admin/reports/fields/views-fields' => '/ALIASprefix/admin/reports/fields/views-fields',
+  '/admin/reports/views-plugins' => '/ALIASprefix/admin/reports/views-plugins',
+  '/admin/structure/views/settings/advanced' => '/ALIASprefix/admin/structure/views/settings/advanced',
+  '/admin/structure/views/settings' => '/ALIASprefix/admin/structure/views/settings',
   '/search/user/help' => '/SEARCH/people/HELP',
 ];