--- /dev/null
+<?php
+
+namespace Drupal\Tests\system\Functional\Update;
+
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\FunctionalTests\Update\UpdatePathTestBase;
+
+/**
+ * Tests hook_post_update().
+ *
+ * @group Update
+ */
+class UpdatePostUpdateTest extends UpdatePathTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setDatabaseDumpFiles() {
+ $this->databaseDumpFiles = [
+ __DIR__ . '/../../../../tests/fixtures/update/drupal-8.bare.standard.php.gz',
+ __DIR__ . '/../../../../tests/fixtures/update/drupal-8.update-test-postupdate-enabled.php',
+ ];
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function doSelectionTest() {
+ parent::doSelectionTest();
+
+ // Ensure that normal and post_update updates are merged together on the
+ // selection page.
+ $this->assertRaw('<ul><li>8001 - Normal update_N() function. </li><li>First update.</li><li>Second update.</li><li>Test0 update.</li><li>Test1 update.</li><li>Testing batch processing in post updates update.</li></ul>');
+ }
+
+ /**
+ * Tests hook_post_update_NAME().
+ */
+ public function testPostUpdate() {
+ $this->runUpdates();
+
+ $this->assertRaw('<h3>Update first</h3>');
+ $this->assertRaw('First update');
+ $this->assertRaw('<h3>Update second</h3>');
+ $this->assertRaw('Second update');
+ $this->assertRaw('<h3>Update test1</h3>');
+ $this->assertRaw('Test1 update');
+ $this->assertRaw('<h3>Update test0</h3>');
+ $this->assertRaw('Test0 update');
+ $this->assertRaw('<h3>Update test_batch</h3>');
+ $this->assertRaw('Test post update batches');
+
+ // Test state value set by each post update.
+ $updates = [
+ 'update_test_postupdate_post_update_first',
+ 'update_test_postupdate_post_update_second',
+ 'update_test_postupdate_post_update_test0',
+ 'update_test_postupdate_post_update_test1',
+ 'update_test_postupdate_post_update_test_batch-1',
+ 'update_test_postupdate_post_update_test_batch-2',
+ 'update_test_postupdate_post_update_test_batch-3',
+ ];
+ $this->assertIdentical($updates, \Drupal::state()->get('post_update_test_execution', []));
+
+ // Test post_update key value stores contains a list of the update functions
+ // that have run.
+ $existing_updates = array_count_values(\Drupal::keyValue('post_update')->get('existing_updates'));
+ $expected_updates = [
+ 'update_test_postupdate_post_update_first',
+ 'update_test_postupdate_post_update_second',
+ 'update_test_postupdate_post_update_test1',
+ 'update_test_postupdate_post_update_test0',
+ 'update_test_postupdate_post_update_test_batch',
+ ];
+ foreach ($expected_updates as $expected_update) {
+ $this->assertEqual($existing_updates[$expected_update], 1, new FormattableMarkup("@expected_update exists in 'existing_updates' key and only appears once.", ['@expected_update' => $expected_update]));
+ }
+
+ $this->drupalGet('update.php/selection');
+ $this->assertText('No pending updates.');
+ }
+
+}