Issue #3523705 by amateescu, rkoller, poker10: InvalidComponentException when...

          'title' => $active_workspace ? $active_workspace->label() : $this->t('Live'),

          'url' => $url,

          'class' => 'workspaces',

          'icon' => [

            'icon_id' => 'workspaces',

          ],

        ],

      ],

      '#attached' => [

<?php

declare(strict_types=1);

namespace Drupal\Tests\navigation\Functional;

use Drupal\Tests\BrowserTestBase;

/**

 * Tests for \Drupal\navigation\WorkspacesLazyBuilder.

 *

 * @group navigation

 */

class NavigationWorkspacesUiTest extends BrowserTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = ['navigation', 'workspaces_ui'];

  /**

   * {@inheritdoc}

   */

  protected $defaultTheme = 'stark';

  /**

   * {@inheritdoc}

   */

  protected function setUp(): void {

    parent::setUp();

    $admin_user = $this->drupalCreateUser([

      'access navigation',

      'administer workspaces',

    ]);

    $this->drupalLogin($admin_user);

  }

  /**

   * Tests the Workspaces button in the navigation bar.

   */

  public function testWorkspacesNavigationButton(): void {

    $this->drupalGet('<front>');

    $this->assertSession()->statusCodeEquals(200);

    $this->assertSession()->elementAttributeContains('css', 'a.toolbar-button--icon--workspaces svg', 'width', '20');

    $this->assertSession()->elementAttributeContains('css', 'a.toolbar-button--icon--workspaces svg', 'class', 'toolbar-button__icon');

  }

}