diff --git a/core/tests/Drupal/FunctionalTests/Theme/ClaroTest.php b/core/tests/Drupal/FunctionalTests/Theme/ClaroTest.php
index 7af61a150552c1f693b829adcbafc3351d180a44..a36ac32792b668f61c3675f5346c8b046b2dc8ab 100644
--- a/core/tests/Drupal/FunctionalTests/Theme/ClaroTest.php
+++ b/core/tests/Drupal/FunctionalTests/Theme/ClaroTest.php
@@ -57,15 +57,13 @@ public function testConfigSchema() {
   }
 
   /**
-   * Tests that the Claro theme can be uninstalled, despite being experimental.
-   *
-   * @todo Remove in https://www.drupal.org/project/drupal/issues/3066007
+   * Tests that the Claro theme can be uninstalled.
    */
   public function testIsUninstallable() {
     $this->drupalLogin($this->drupalCreateUser(['access administration pages', 'administer themes']));
 
     $this->drupalGet('admin/appearance');
-    $this->cssSelect('a[title="Install Seven as default theme"]')[0]->click();
+    $this->cssSelect('a[title="Install <strong>Test theme</strong> as default theme"]')[0]->click();
     $this->cssSelect('a[title="Uninstall Claro theme"]')[0]->click();
     $this->assertSession()->pageTextContains('The Claro theme has been uninstalled.');
   }
diff --git a/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php b/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
index 4a0e8d09d4034920994b8eab7172ab60012689c7..b31b9bafb43b8f7234ff6c654bdcd63e75828f0b 100644
--- a/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
+++ b/core/tests/Drupal/FunctionalTests/Theme/OliveroTest.php
@@ -124,7 +124,7 @@ public function testIsUninstallable() {
     ]));
 
     $this->drupalGet('admin/appearance');
-    $this->cssSelect('a[title="Install Bartik as default theme"]')[0]->click();
+    $this->cssSelect('a[title="Install <strong>Test theme</strong> as default theme"]')[0]->click();
     $this->cssSelect('a[title="Uninstall Olivero theme"]')[0]->click();
     $this->assertSession()->pageTextContains('The Olivero theme has been uninstalled.');
   }
diff --git a/core/tests/Drupal/FunctionalTests/Theme/BartikTest.php b/core/themes/bartik/tests/src/Functional/BartikTest.php
similarity index 94%
rename from core/tests/Drupal/FunctionalTests/Theme/BartikTest.php
rename to core/themes/bartik/tests/src/Functional/BartikTest.php
index 86cf7de9e2e8ec0749e40441e509a5d559219f44..7c70c2fcd392b30504ded3bd26174dde1a98ad0d 100644
--- a/core/tests/Drupal/FunctionalTests/Theme/BartikTest.php
+++ b/core/themes/bartik/tests/src/Functional/BartikTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\FunctionalTests\Theme;
+namespace Drupal\Tests\bartik\Functional;
 
 use Drupal\Tests\BrowserTestBase;
 
diff --git a/core/tests/Drupal/FunctionalTests/Theme/SevenLayoutBuilderTest.php b/core/themes/seven/tests/src/Functional/SevenLayoutBuilderTest.php
similarity index 98%
rename from core/tests/Drupal/FunctionalTests/Theme/SevenLayoutBuilderTest.php
rename to core/themes/seven/tests/src/Functional/SevenLayoutBuilderTest.php
index f738f125614f7442a7b3310d97e6f8ec6cc153ff..e39bfaa3b3c8198f484be20325def4b32616a1ca 100644
--- a/core/tests/Drupal/FunctionalTests/Theme/SevenLayoutBuilderTest.php
+++ b/core/themes/seven/tests/src/Functional/SevenLayoutBuilderTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace Drupal\FunctionalTests\Theme;
+namespace Drupal\Tests\seven\Functional;
 
 use Drupal\Tests\BrowserTestBase;