setInitMessage example

public function submitForm(array &$form, FormStateInterface $form_state) {
    $this->moduleHandler->loadInclude('update', 'inc', 'update.manager');
    $projects = [];
    foreach (['projects', 'disabled_projects'] as $type) {
      if (!$form_state->isValueEmpty($type)) {
        $projects = array_merge($projects, array_keys(array_filter($form_state->getValue($type))));
      }
    }
    $batch_builder = (new BatchBuilder())
      ->setFile($this->moduleHandler->getModule('update')->getPath() . '/update.manager.inc')
      ->setTitle($this->t('Downloading updates'))
      ->setInitMessage($this->t('Preparing to download selected updates'))
      ->setFinishCallback('update_manager_download_batch_finished');
    foreach ($projects as $project) {
      $batch_builder->addOperation('update_manager_batch_project_get', [
        $project,
        $form_state->getValue(['project_downloads', $project]),
      ]);
    }
    batch_set($batch_builder->toArray());
  }

}

$this->themeExtensionList
    );
    if ($config_importer->alreadyImporting()) {
      $this->messenger()->addStatus($this->t('Another request may be synchronizing configuration already.'));
    }
    else {
      try {
        $sync_steps = $config_importer->initialize();
        $batch_builder = (new BatchBuilder())
          ->setTitle($this->t('Synchronizing configuration'))
          ->setFinishCallback([ConfigImporterBatch::class, 'finish'])
          ->setInitMessage($this->t('Starting configuration synchronization.'))
          ->setProgressMessage($this->t('Completed step @current of @total.'))
          ->setErrorMessage($this->t('Configuration synchronization has encountered an error.'));
        foreach ($sync_steps as $sync_step) {
          $batch_builder->addOperation([ConfigImporterBatch::class, 'process'], [$config_importer, $sync_step]);
        }

        batch_set($batch_builder->toArray());
      }
      catch (ConfigImporterException $e) {
        // There are validation errors.         $this->messenger()->addError($this->t('The configuration cannot be imported because it failed validation for the following reasons:'));
        

$this->assertEquals('\Drupal\Tests\Core\Batch\BatchBuilderTest::finishedCallback', $batch['finished']);
  }

  /** * Tests setInitMessage(). * * @covers ::setInitMessage */
  public function testSetInitMessage() {
    $batch = (new BatchBuilder())
      ->setInitMessage(new TranslatableMarkup('New initialization message.'))
      ->toArray();

    $this->assertEquals(new TranslatableMarkup('New initialization message.'), $batch['init_message']);
  }

  /** * Tests setProgressMessage(). * * @covers ::setProgressMessage */
  public function testSetProgressMessage() {
    

    // be restored at the end of the batch.     $request->getSession()->set('maintenance_mode', $maintenance_mode);
    // During the update, always put the site into maintenance mode so that     // in-progress schema changes do not affect visiting users.     if (empty($maintenance_mode)) {
      $this->state->set('system.maintenance_mode', TRUE);
    }

    /** @var \Drupal\Core\Batch\BatchBuilder $batch_builder */
    $batch_builder = (new BatchBuilder())
      ->setTitle($this->t('Updating'))
      ->setInitMessage($this->t('Starting updates'))
      ->setErrorMessage($this->t('An unrecoverable error has occurred. You can find the error message below. It is advised to copy it to the clipboard for reference.'))
      ->setFinishCallback([DbUpdateController::class, 'batchFinished']);

    // Resolve any update dependencies to determine the actual updates that will     // be run and the order they will be run in.     $start = $this->getModuleUpdates();
    $updates = update_resolve_dependencies($start);

    // Store the dependencies for each update function in an array which the     // batch API can pass in to the batch operation each time it is called. (We     // do not store the entire update dependency array here because it is

/** @var \Drupal\Core\Config\ConfigImporter $config_importer */
    $config_importer = $form_state->get('config_importer');
    if ($config_importer->alreadyImporting()) {
      $this->messenger()->addError($this->t('Another request may be importing configuration already.'));
    }
    else {
      try {
        $sync_steps = $config_importer->initialize();
        $batch_builder = (new BatchBuilder())
          ->setTitle($this->t('Importing configuration'))
          ->setFinishCallback([ConfigImporterBatch::class, 'finish'])
          ->setInitMessage($this->t('Starting configuration import.'))
          ->setProgressMessage($this->t('Completed @current step of @total.'))
          ->setErrorMessage($this->t('Configuration import has encountered an error.'));
        foreach ($sync_steps as $sync_step) {
          $batch_builder->addOperation([ConfigImporterBatch::class, 'process'], [$config_importer, $sync_step]);
        }
        batch_set($batch_builder->toArray());
      }
      catch (ConfigImporterException $e) {
        // There are validation errors.         $this->messenger()->addError($this->t('The configuration import failed for the following reasons:'));
        foreach ($config_importer->getErrors() as $message) {