assertSaveLayout example

'administer node fields',
      'create and edit custom blocks',
    ]));

    // Enable layout builder.     $this->drupalGet(static::FIELD_UI_PREFIX . '/display/default');
    $this->submitForm(['layout[enabled]' => TRUE], 'Save');
    $this->clickLink('Manage layout');
    $assert_session->addressEquals(static::FIELD_UI_PREFIX . '/display/default/layout');
    // Add a basic block with the body field set.     $this->addInlineBlockToLayout('Block title', 'The DEFAULT block body');
    $this->assertSaveLayout();

    $this->drupalGet('node/1');
    $assert_session->pageTextContains('The DEFAULT block body');
    $this->drupalGet('node/2');
    $assert_session->pageTextContains('The DEFAULT block body');

    // Enable overrides.     $this->drupalGet(static::FIELD_UI_PREFIX . '/display/default');
    $this->submitForm(['layout[allow_custom]' => TRUE], 'Save');
    $this->drupalGet('node/1/layout');

    

'create and edit custom blocks',
    ]));
    $this->drupalGet('node/1/layout');
    // @todo Occasionally SQLite has database locks here. Waiting seems to     // resolve it. https://www.drupal.org/project/drupal/issues/3055983     $assert_session->assertWaitOnAjaxRequest();
    $file = $this->createPrivateFile('drupal.txt');

    $file_real_path = $this->fileSystem->realpath($file->getFileUri());
    $this->assertFileExists($file_real_path);
    $this->addInlineFileBlockToLayout('The file', $file);
    $this->assertSaveLayout();

    $this->drupalGet('node/1');
    $private_href1 = $this->getFileHrefAccessibleOnNode($file);

    // Remove the inline block with the private file.     $this->drupalGet('node/1/layout');
    $this->removeInlineBlockFromLayout();
    $this->assertSaveLayout();

    $this->drupalGet('node/1');
    $assert_session->pageTextNotContains($file->label());