Issue #3309475 by sorabh.v6: Write tests to invalidate cache when settings are changed

    $this->assertSame($render_counter, $state->get('render_counter'));

  }

  /**

   * Tests that cache gets invalidated upon trailless_menu form save if form

   * setting is changed.

   */

  function testCacheInvalidationOnFormSave() {

    /** @var \Drupal\Core\Cache\DatabaseCacheTagsChecksum $cacheTagChecksum **/

    $cacheTagChecksum = \Drupal::service('cache_tags.invalidator.checksum');

    // Create menu links for footer menu.

    $this->first_item = MenuLinkContent::create([

      'link' => 'https://example.com',

      'title' => 'footer1',

      'menu_name' => 'footer',

    ]);

    $this->first_item->save();

    $this->second_item = MenuLinkContent::create([

      'link' => 'https://example.com/footer2',

      'title' => 'footer2',

      'menu_name' => 'footer',

    ]);

    $this->second_item->save();

    // Place footer menu on the page.

    $this->block = $this->drupalPlaceBlock(

      'system_menu_block:footer',

      [

        'label' => 'trailless_menu footer navigation'

      ]

    );

    // Goto home page or some other page.

    $this->drupalGet('');

    // Goto trailless menu config page.

    $this->drupalGet('/admin/config/user-interface/trailless-menu');

    // Check cachetag count for tag reset of main and footer.

    $mainMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.main']);

    $footerMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.footer']);

    // Tick footer in the config page and save config.

    $edit = [

      'trailless_menus[main]' => TRUE,

      'trailless_menus[footer]' => TRUE,

    ];

    $this->submitForm($edit, 'Save configuration');

    // Check that main menu cachetag count is same and for footer is changed.

    $newMainMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.main']);

    $newFooterMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.footer']);

    $this->assertSame($mainMenuCount, $newMainMenuCount);

    $this->assertNotSame($footerMenuCount, $newFooterMenuCount);

    // Untick main menu and save config.

    $this->drupalGet('/admin/config/user-interface/trailless-menu');

    $edit['trailless_menus[main]'] = FALSE;

    $this->submitForm($edit, 'Save configuration');

    // Check that footer menu cachetag count is same and for main menu is changed.

    $mainMenuCount = $newMainMenuCount;

    $footerMenuCount = $newFooterMenuCount;

    $newMainMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.main']);

    $newFooterMenuCount = $cacheTagChecksum

      ->getCurrentChecksum(['config:system.menu.footer']);

    $this->assertNotSame($mainMenuCount, $newMainMenuCount);

    $this->assertSame($footerMenuCount, $newFooterMenuCount);

  }

}