setSetting('maintenance_theme', 'seven'); // Get the maintenance theme loaded. drupal_maintenance_theme(); // Do we have an active theme? $this->assertTrue(\Drupal::theme()->hasActiveTheme()); $active_theme = \Drupal::theme()->getActiveTheme(); $this->assertEquals('seven', $active_theme->getName()); $base_themes = $active_theme->getBaseThemeExtensions(); $base_theme_names = array_keys($base_themes); $this->assertSame(['classy', 'stable'], $base_theme_names); } }