Issue #3248816 by bsuttis, danflanagan8, quietone:...

Issue #3248816 by bsuttis, danflanagan8, quietone: ResponsiveImageFieldUiTest.php should be moved to tests directory

core/modules/responsive_image/src/FunctionalJavascript/ResponsiveImageFieldUiTest.php → core/modules/responsive_image/tests/src/FunctionalJavascript/ResponsiveImageFieldUiTest.php

 <?php
 
-namespace Drupal\responsive_image\Tests;
+namespace Drupal\Tests\responsive_image\FunctionalJavascript;
 
 use Drupal\FunctionalJavascriptTests\WebDriverTestBase;
 use Drupal\responsive_image\Entity\ResponsiveImageStyle;
@@ -12,6 +12,11 @@
  */
 class ResponsiveImageFieldUiTest extends WebDriverTestBase {
 
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
   /**
    * Modules to install.
    *