--- /dev/null
+<?php
+
+namespace Drupal\Tests\block\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests the block administration page for a non-default theme.
+ *
+ * @group block
+ */
+class NonDefaultBlockAdminTest extends BrowserTestBase {
+
+ /**
+ * Modules to install.
+ *
+ * @var array
+ */
+ public static $modules = ['block'];
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setUp() {
+ parent::setUp();
+
+ $this->drupalPlaceBlock('local_tasks_block');
+ }
+
+ /**
+ * Test non-default theme admin.
+ */
+ public function testNonDefaultBlockAdmin() {
+ $admin_user = $this->drupalCreateUser(['administer blocks', 'administer themes']);
+ $this->drupalLogin($admin_user);
+ $new_theme = 'bartik';
+ \Drupal::service('theme_handler')->install([$new_theme]);
+ $this->drupalGet('admin/structure/block/list/' . $new_theme);
+ $this->assertText('Bartik(' . t('active tab') . ')', 'Tab for non-default theme found.');
+ }
+
+}