diff --git a/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
index d6171ec831..cdaaea5227 100644
--- a/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
+++ b/core/modules/system/tests/src/Functional/Theme/ThemeUiTest.php
@@ -64,8 +64,8 @@ public function testThemeInstallWithModuleDependencies($theme_name) {
     $page = $this->getSession()->getPage();
     $this->drupalGet('admin/appearance');
     $expected_requires_list_items = [
-      'test module required by theme (disabled)',
-      'test another module required by theme (disabled)',
+      'Test Module Required by Theme (disabled)',
+      'Test Another Module Required by Theme (disabled)',
     ];
     $this->assertUninstallableTheme($expected_requires_list_items, $theme_name);
 
@@ -80,7 +80,7 @@ public function testThemeInstallWithModuleDependencies($theme_name) {
     // Confirm the theme is still uninstallable due to a remaining module
     // dependency.
     $expected_requires_list_items = [
-      'test another module required by theme (disabled)',
+      'Test Another Module Required by Theme (disabled)',
     ];
     $this->assertUninstallableTheme($expected_requires_list_items, $theme_name);
 
@@ -92,9 +92,9 @@ public function testThemeInstallWithModuleDependencies($theme_name) {
 
     // The theme should now be installable, so install it.
     $this->drupalGet('admin/appearance');
-    $page->clickLink('Install test theme depending on modules theme');
+    $page->clickLink('Install Test Theme Depending on Modules theme');
     $assert_session->addressEquals('admin/appearance');
-    $assert_session->pageTextContains('The test theme depending on modules theme has been installed');
+    $assert_session->pageTextContains('The Test Theme Depending on Modules theme has been installed');
 
     // Confirm that the dependee modules can't be uninstalled because an enabled
     // theme depends on them.
@@ -107,8 +107,8 @@ public function testThemeInstallWithModuleDependencies($theme_name) {
     // Uninstall the theme that depends on the modules, and confirm the modules
     // can now be uninstalled.
     $this->drupalGet('admin/appearance');
-    $this->clickLink('Uninstall test theme depending on modules theme');
-    $assert_session->pageTextContains('The test theme depending on modules theme has been uninstalled.');
+    $this->clickLink('Uninstall Test Theme Depending on Modules theme');
+    $assert_session->pageTextContains('The Test Theme Depending on Modules theme has been uninstalled.');
     $this->drupalGet('admin/modules/uninstall');
     $assert_session->elementExists('css', '[name="uninstall[test_module_required_by_theme]"]:not([disabled])');
     $assert_session->elementExists('css', '[name="uninstall[test_another_module_required_by_theme]"]:not([disabled])');
@@ -127,8 +127,8 @@ public function testThemeInstallWithModuleDependencies($theme_name) {
    */
   public function providerTestThemeInstallWithModuleDependencies() {
     return [
-      'test theme depending on modules' => ['test theme depending on modules'],
-      'test theme with a base theme depending on modules' => ['test theme with a base theme depending on modules'],
+      'test theme depending on modules' => ['Test Theme Depending on Modules'],
+      'test theme with a base theme depending on modules' => ['Test Theme with a Base Theme Depending on Modules'],
     ];
   }
 
@@ -151,7 +151,7 @@ protected function assertUninstallableTheme(array $expected_requires_list_items,
     $incompatible = $theme_container->find('css', '.incompatible');
     $expected_incompatible_text = 'This theme requires the listed modules to operate correctly. They must first be enabled via the Extend page.';
     $this->assertSame($expected_incompatible_text, $incompatible->getText());
-    $this->assertFalse($theme_container->hasLink('Install test theme depending on modules theme'));
+    $this->assertFalse($theme_container->hasLink('Install Test Theme Depending on Modules theme'));
   }
 
   /**
@@ -159,7 +159,7 @@ protected function assertUninstallableTheme(array $expected_requires_list_items,
    */
   public function testInstallModuleWithMissingDependencies() {
     $this->drupalGet('admin/appearance');
-    $theme_container = $this->getSession()->getPage()->find('css', 'h3:contains("test theme depending on nonexisting module")')->getParent();
+    $theme_container = $this->getSession()->getPage()->find('css', 'h3:contains("Test Theme Depending on Nonexisting Module")')->getParent();
     $this->assertContains('missing', $theme_container->getText());
     $this->assertContains('This theme requires the listed modules to operate correctly.', $theme_container->getText());
   }