assertLinksFormIframeNotInteractive example

$this->submitForm(['layout[enabled]' => TRUE], 'Save');
    $assert_session->linkExists('Manage layout');
    $this->clickLink('Manage layout');

    // Add a block with a form, another with a link, and one with an iframe.     $this->addBlock('Search form', '#layout-builder .search-block-form');
    $this->addBlock('Block with link', '#link-that-should-be-disabled');
    $this->addBlock('Block with iframe', '#iframe-that-should-be-disabled');

    // Ensure the links and forms are disabled using the defaults before the     // layout is saved.     $this->assertLinksFormIframeNotInteractive();

    $page->pressButton('Save layout');
    $this->clickLink('Manage layout');

    // Ensure the links and forms are disabled using the defaults.     $this->assertLinksFormIframeNotInteractive();

    // Ensure contextual links were not disabled.     $this->assertContextualLinksClickable();

    $this->drupalGet("{$field_ui_prefix}/display/default");