Issue #2715663 by ravi.shankar, andrewmacpherson, waako, yogeshmpawar,...

          $details.attr('open', true).each(hidePackageDetails);

          Drupal.announce(

            Drupal.t('!modules modules are available in the modified list.', {

              '!modules': $rowsAndDetails.find('tbody tr:visible').length,

            }),

            Drupal.formatPlural(

              $rowsAndDetails.find('tbody tr:visible').length,

              '1 module is available in the modified list.',

              '@count modules are available in the modified list.',

            ),

          );

        } else if (searching) {

          searching = false;

<?php

namespace Drupal\Tests\system\FunctionalJavascript;

use Drupal\FunctionalJavascriptTests\WebDriverTestBase;

/**

 * Tests the JavaScript functionality of the module filter.

 *

 * @group system

 */

class ModuleFilterTest extends WebDriverTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = ['user', 'system'];

  /**

   * {@inheritdoc}

   */

  protected $defaultTheme = 'stark';

  /**

   * {@inheritdoc}

   */

  protected function setUp(): void {

    parent::setUp();

    $admin_user = $this->drupalCreateUser([

      'administer modules',

    ]);

    $this->drupalLogin($admin_user);

  }

  /**

   * Tests that filter results announcement has correct pluralization.

   */

  public function testModuleFilter() {

    // Find the module filter field.

    $this->drupalGet('admin/modules');

    $assertSession = $this->assertSession();

    $session = $this->getSession();

    $page = $session->getPage();

    $filter = $page->findField('edit-text');

    // Get all module rows, for assertions later.

    $module_rows = $page->findAll('css', '.package-listing tbody tr td.module');

    // Test module filter reduces the number of visible rows.

    $filter->setValue('test');

    $session->wait(1000, 'jQuery("#module-node:visible").length == 0');

    $visible_rows = $this->filterVisibleElements($module_rows);

    // Test Drupal.announce() message when multiple matches are expected.

    $expected_message = count($visible_rows) . ' modules are available in the modified list.';

    $assertSession->elementTextContains('css', '#drupal-live-announce', $expected_message);

    self::assertGreaterThan(count($visible_rows), count($module_rows));

    self::assertGreaterThan(1, count($visible_rows));

    // Test Drupal.announce() message when one match is expected.

    // Using a very specific module name, we expect only one row.

    $filter->setValue('System dependency test');

    $session->wait(1000, 'jQuery("#module-node:visible").length == 0');

    $visible_rows = $this->filterVisibleElements($module_rows);

    self::assertEquals(1, count($visible_rows));

    $expected_message = '1 module is available in the modified list.';

    $assertSession->elementTextContains('css', '#drupal-live-announce', $expected_message);

    // Test Drupal.announce() message when no matches are expected.

    $filter->setValue('Pan-Galactic Gargle Blaster');

    $session->wait(1000, 'jQuery("#module-node:visible").length == 0');

    $visible_rows = $this->filterVisibleElements($module_rows);

    self::assertEquals(0, count($visible_rows));

    $expected_message = '0 modules are available in the modified list.';

    $assertSession->elementTextContains('css', '#drupal-live-announce', $expected_message);

  }

  /**

   * Removes any non-visible elements from the passed array.

   *

   * @param \Behat\Mink\Element\NodeElement[] $elements

   *   An array of node elements.

   *

   * @return \Behat\Mink\Element\NodeElement[]

   *   An array of node elements.

   */

  protected function filterVisibleElements(array $elements): array {

    $elements = array_filter($elements, function ($element) {

      return $element->isVisible();

    });

    return $elements;

  }

}