diff --git a/core/includes/batch.inc b/core/includes/batch.inc
index fbbcd09..2640fc4 100644
--- a/core/includes/batch.inc
+++ b/core/includes/batch.inc
@@ -205,316 +205,6 @@ function _batch_progress_page() {
 }
 
 /**
- * Processes sets in a batch.
- *
- * If the batch was marked for progressive execution (default), this executes as
- * many operations in batch sets until an execution time of 1 second has been
- * exceeded. It will continue with the next operation of the same batch set in
- * the next request.
- *
- * @return
- *   An array containing a completion value (in percent) and a status message.
- */
-function _batch_process() {
-  $batch       = &batch_get();
-  $current_set = &_batch_current_set();
-  // Indicate that this batch set needs to be initialized.
-  $set_changed = TRUE;
-
-  // If this batch was marked for progressive execution (e.g. forms submitted by
-  // \Drupal::formBuilder()->submitForm(), initialize a timer to determine
-  // whether we need to proceed with the same batch phase when a processing time
-  // of 1 second has been exceeded.
-  if ($batch['progressive']) {
-    Timer::start('batch_processing');
-  }
-
-  if (empty($current_set['start'])) {
-    $current_set['start'] = microtime(TRUE);
-  }
-
-  $queue = _batch_queue($current_set);
-
-  while (!$current_set['success']) {
-    // If this is the first time we iterate this batch set in the current
-    // request, we check if it requires an additional file for functions
-    // definitions.
-    if ($set_changed && isset($current_set['file']) && is_file($current_set['file'])) {
-      include_once \Drupal::root() . '/' . $current_set['file'];
-    }
-
-    $task_message = $label = '';
-    // Assume a single pass operation and set the completion level to 1 by
-    // default.
-    $finished = 1;
-
-    if ($item = $queue->claimItem()) {
-      list($callback, $args) = $item->data;
-
-      // Build the 'context' array and execute the function call.
-      $batch_context = array(
-        'sandbox'  => &$current_set['sandbox'],
-        'results'  => &$current_set['results'],
-        'finished' => &$finished,
-        'message'  => &$task_message,
-      );
-      call_user_func_array($callback, array_merge($args, array(&$batch_context)));
-
-      if ($finished >= 1) {
-        // Make sure this step is not counted twice when computing $current.
-        $finished = 0;
-        // Remove the processed operation and clear the sandbox.
-        $queue->deleteItem($item);
-        $current_set['count']--;
-        $current_set['sandbox'] = array();
-      }
-    }
-
-    // When all operations in the current batch set are completed, browse
-    // through the remaining sets, marking them 'successfully processed'
-    // along the way, until we find a set that contains operations.
-    // _batch_next_set() executes form submit handlers stored in 'control'
-    // sets (see \Drupal::service('form_submitter')), which can in turn add new
-    // sets to the batch.
-    $set_changed = FALSE;
-    $old_set = $current_set;
-    while (empty($current_set['count']) && ($current_set['success'] = TRUE) && _batch_next_set()) {
-      $current_set = &_batch_current_set();
-      $current_set['start'] = microtime(TRUE);
-      $set_changed = TRUE;
-    }
-
-    // At this point, either $current_set contains operations that need to be
-    // processed or all sets have been completed.
-    $queue = _batch_queue($current_set);
-
-    // If we are in progressive mode, break processing after 1 second.
-    if ($batch['progressive'] && Timer::read('batch_processing') > 1000) {
-      // Record elapsed wall clock time.
-      $current_set['elapsed'] = round((microtime(TRUE) - $current_set['start']) * 1000, 2);
-      break;
-    }
-  }
-
-  if ($batch['progressive']) {
-    // Gather progress information.
-
-    // Reporting 100% progress will cause the whole batch to be considered
-    // processed. If processing was paused right after moving to a new set,
-    // we have to use the info from the new (unprocessed) set.
-    if ($set_changed && isset($current_set['queue'])) {
-      // Processing will continue with a fresh batch set.
-      $remaining        = $current_set['count'];
-      $total            = $current_set['total'];
-      $progress_message = $current_set['init_message'];
-      $task_message     = '';
-    }
-    else {
-      // Processing will continue with the current batch set.
-      $remaining        = $old_set['count'];
-      $total            = $old_set['total'];
-      $progress_message = $old_set['progress_message'];
-    }
-
-    // Total progress is the number of operations that have fully run plus the
-    // completion level of the current operation.
-    $current    = $total - $remaining + $finished;
-    $percentage = _batch_api_percentage($total, $current);
-    $elapsed    = isset($current_set['elapsed']) ? $current_set['elapsed'] : 0;
-    $values     = array(
-      '@remaining'  => $remaining,
-      '@total'      => $total,
-      '@current'    => floor($current),
-      '@percentage' => $percentage,
-      '@elapsed'    => \Drupal::service('date.formatter')->formatInterval($elapsed / 1000),
-      // If possible, estimate remaining processing time.
-      '@estimate'   => ($current > 0) ? \Drupal::service('date.formatter')->formatInterval(($elapsed * ($total - $current) / $current) / 1000) : '-',
-    );
-    $message = strtr($progress_message, $values);
-    if (!empty($task_message)) {
-      $label = $task_message;
-    }
-
-    return array($percentage, $message, $label);
-  }
-  else {
-    // If we are not in progressive mode, the entire batch has been processed.
-    return _batch_finished();
-  }
-}
-
-/**
- * Formats the percent completion for a batch set.
- *
- * @param $total
- *   The total number of operations.
- * @param $current
- *   The number of the current operation. This may be a floating point number
- *   rather than an integer in the case of a multi-step operation that is not
- *   yet complete; in that case, the fractional part of $current represents the
- *   fraction of the operation that has been completed.
- *
- * @return
- *   The properly formatted percentage, as a string. We output percentages
- *   using the correct number of decimal places so that we never print "100%"
- *   until we are finished, but we also never print more decimal places than
- *   are meaningful.
- *
- * @see _batch_process()
- */
-function _batch_api_percentage($total, $current) {
-  return Percentage::format($total, $current);
-}
-
-/**
- * Returns the batch set being currently processed.
- */
-function &_batch_current_set() {
-  $batch = &batch_get();
-  return $batch['sets'][$batch['current_set']];
-}
-
-/**
- * Retrieves the next set in a batch.
- *
- * If there is a subsequent set in this batch, assign it as the new set to
- * process and execute its form submit handler (if defined), which may add
- * further sets to this batch.
- *
- * @return
- *   TRUE if a subsequent set was found in the batch.
- */
-function _batch_next_set() {
-  $batch = &batch_get();
-  if (isset($batch['sets'][$batch['current_set'] + 1])) {
-    $batch['current_set']++;
-    $current_set = &_batch_current_set();
-    if (isset($current_set['form_submit']) && ($callback = $current_set['form_submit']) && is_callable($callback)) {
-      // We use our stored copies of $form and $form_state to account for
-      // possible alterations by previous form submit handlers.
-      $complete_form = &$batch['form_state']->getCompleteForm();
-      call_user_func_array($callback, array(&$complete_form, &$batch['form_state']));
-    }
-    return TRUE;
-  }
-}
-
-/**
- * Ends the batch processing.
- *
- * Call the 'finished' callback of each batch set to allow custom handling of
- * the results and resolve page redirection.
- */
-function _batch_finished() {
-  $batch = &batch_get();
-  $batch_finished_redirect = NULL;
-
-  // Execute the 'finished' callbacks for each batch set, if defined.
-  foreach ($batch['sets'] as $batch_set) {
-    if (isset($batch_set['finished'])) {
-      // Check if the set requires an additional file for function definitions.
-      if (isset($batch_set['file']) && is_file($batch_set['file'])) {
-        include_once \Drupal::root() . '/' . $batch_set['file'];
-      }
-      if (is_callable($batch_set['finished'])) {
-        $queue = _batch_queue($batch_set);
-        $operations = $queue->getAllItems();
-        $batch_set_result = call_user_func_array($batch_set['finished'], array($batch_set['success'], $batch_set['results'], $operations, \Drupal::service('date.formatter')->formatInterval($batch_set['elapsed'] / 1000)));
-        // If a batch 'finished' callback requested a redirect after the batch
-        // is complete, save that for later use. If more than one batch set
-        // returned a redirect, the last one is used.
-        if ($batch_set_result instanceof RedirectResponse) {
-          $batch_finished_redirect = $batch_set_result;
-        }
-      }
-    }
-  }
-
-  // Clean up the batch table and unset the static $batch variable.
-  if ($batch['progressive']) {
-    \Drupal::service('batch.storage')->delete($batch['id']);
-    foreach ($batch['sets'] as $batch_set) {
-      if ($queue = _batch_queue($batch_set)) {
-        $queue->deleteQueue();
-      }
-    }
-    // Clean-up the session. Not needed for CLI updates.
-    if (isset($_SESSION)) {
-      unset($_SESSION['batches'][$batch['id']]);
-      if (empty($_SESSION['batches'])) {
-        unset($_SESSION['batches']);
-      }
-    }
-  }
-  $_batch = $batch;
-  $batch = NULL;
-
-  // Redirect if needed.
-  if ($_batch['progressive']) {
-    // Revert the 'destination' that was saved in batch_process().
-    if (isset($_batch['destination'])) {
-      \Drupal::request()->query->set('destination', $_batch['destination']);
-    }
-
-    // Determine the target path to redirect to. If a batch 'finished' callback
-    // returned a redirect response object, use that. Otherwise, fall back on
-    // the form redirection.
-    if (isset($batch_finished_redirect)) {
-      return $batch_finished_redirect;
-    }
-    elseif (!isset($_batch['form_state'])) {
-      $_batch['form_state'] = new FormState();
-    }
-    if ($_batch['form_state']->getRedirect() === NULL) {
-      $redirect = $_batch['batch_redirect'] ?: $_batch['source_url'];
-      // Any path with a scheme does not correspond to a route.
-      if (!$redirect instanceof Url) {
-        $options = UrlHelper::parse($redirect);
-        if (parse_url($options['path'], PHP_URL_SCHEME)) {
-          $redirect = Url::fromUri($options['path'], $options);
-        }
-        else {
-          $redirect = \Drupal::pathValidator()->getUrlIfValid($options['path']);
-          if (!$redirect) {
-            // Stay on the same page if the redirect was invalid.
-            $redirect = Url::fromRoute('<current>');
-          }
-          $redirect->setOptions($options);
-        }
-      }
-      $_batch['form_state']->setRedirectUrl($redirect);
-    }
-
-    // Use \Drupal\Core\Form\FormSubmitterInterface::redirectForm() to handle
-    // the redirection logic.
-    $redirect = \Drupal::service('form_submitter')->redirectForm($_batch['form_state']);
-    if (is_object($redirect)) {
-      return $redirect;
-    }
-
-    // If no redirection happened, redirect to the originating page. In case the
-    // form needs to be rebuilt, save the final $form_state for
-    // \Drupal\Core\Form\FormBuilderInterface::buildForm().
-    if ($_batch['form_state']->isRebuilding()) {
-      $_SESSION['batch_form_state'] = $_batch['form_state'];
-    }
-    $callback = $_batch['redirect_callback'];
-    /** @var \Drupal\Core\Url $source_url */
-    $source_url = $_batch['source_url'];
-    if (is_callable($callback)) {
-      $callback($_batch['source_url'], array('query' => array('op' => 'finish', 'id' => $_batch['id'])));
-    }
-    elseif ($callback === NULL) {
-      // Default to RedirectResponse objects when nothing specified.
-      $url = $source_url
-        ->setAbsolute()
-        ->setOption('query', ['op' => 'finish', 'id' => $_batch['id']]);
-      return new RedirectResponse($url->toString());
-    }
-  }
-}
-
-/**
  * Shutdown function: Stores the current batch data for the next request.
  *
  * @see _batch_page()
diff --git a/core/tests/Drupal/Tests/Core/Batch/BatchProcessorTest.php b/core/tests/Drupal/Tests/Core/Batch/BatchProcessorTest.php
index 198b796..45c7033 100644
--- a/core/tests/Drupal/Tests/Core/Batch/BatchProcessorTest.php
+++ b/core/tests/Drupal/Tests/Core/Batch/BatchProcessorTest.php
@@ -7,6 +7,11 @@
 
 namespace Drupal\Tests\Core\Batch;
 
-class BatchProcessorTest {
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Batch\BatchProcessor
+ */
+class BatchProcessorTest extends UnitTestCase {
 
 }