diff --git a/core/modules/system/src/Tests/Update/SiteBrandingConvertedIntoBlockUpdateTest.php b/core/modules/system/src/Tests/Update/SiteBrandingConvertedIntoBlockUpdateTest.php
new file mode 100644
index 0000000..73e681b
--- /dev/null
+++ b/core/modules/system/src/Tests/Update/SiteBrandingConvertedIntoBlockUpdateTest.php
@@ -0,0 +1,64 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\Update\LocalActionsAndTasksConvertedIntoBlocksUpdateTest.
+ */
+
+namespace Drupal\system\Tests\Update;
+
+use Drupal\node\Entity\Node;
+
+/**
+ * Tests the upgrade path for local actions/tasks being converted into blocks.
+ *
+ * @see https://www.drupal.org/node/507488
+ *
+ * @group system
+ */
+class SiteBrandingConvertedIntoBlockUpdateTest extends UpdatePathTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    $this->databaseDumpFiles = [
+      __DIR__ . '/../../../../system/tests/fixtures/update/drupal-8.bare.standard.php.gz',
+      __DIR__ . '/../../../../system/tests/fixtures/update/drupal-8.site-branding-into-block-2005546.php',
+    ];
+    parent::setUp();
+  }
+
+  /**
+   * Tests that site branding elements are being converted into blocks.
+   */
+  public function testUpdateHookN() {
+    $this->runUpdates();
+
+    /** @var \Drupal\block\BlockInterface $block_storage */
+    $block_storage = \Drupal::entityManager()->getStorage('block');
+
+    $this->assertRaw('Because your site has custom theme(s) installed, we had to set the branding block into the content region. Please manually review the block configuration and remove the site name, slogan, and logo variables from your templates.');
+
+    // Disable maintenance mode.
+    // @todo Can be removed once maintenance mode is automatically turned off
+    // after updates in https://www.drupal.org/node/2435135.
+    \Drupal::state()->set('system.maintenance_mode', FALSE);
+
+    // We finished updating so we can login the user now.
+    $this->drupalLogin($this->rootUser);
+
+    // Site branding is visible on the home page.
+    $this->drupalGet('/');
+    $this->assertRaw('site-branding__logo');
+    $this->assertRaw('site-branding__name');
+    $this->assertRaw('site-branding__slogan');
+
+    $this->drupalGet('admin/structure/block/list/bartik');
+
+    /** @var \Drupal\Core\Config\StorageInterface $config_storage */
+    $config_storage = \Drupal::service('config.storage');
+    $this->assertTrue($config_storage->exists('block.block.test_theme_branding'), 'Site branding block has been created for the custom theme.');
+  }
+
+}
diff --git a/core/modules/system/tests/fixtures/update/block.block.testfor2005546.yml b/core/modules/system/tests/fixtures/update/block.block.testfor2005546.yml
new file mode 100644
index 0000000..4396c75
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/block.block.testfor2005546.yml
@@ -0,0 +1,25 @@
+uuid: b299258f-6fb5-47f8-b42f-473787d02e22
+langcode: en
+status: true
+dependencies:
+  module:
+    - system
+  theme:
+    - bartik
+id: bartik_branding
+theme: bartik
+region: header
+weight: 0
+provider: null
+plugin: system_branding_block
+settings:
+  id: system_branding_block
+  label: 'Site Branding'
+  provider: system
+  label_display: '0'
+  cache:
+    max_age: -1
+  use_site_logo: true
+  use_site_name: true
+  use_site_slogan: true
+visibility: {  }
diff --git a/core/modules/system/tests/fixtures/update/drupal-8.site-branding-into-block-2005546.php b/core/modules/system/tests/fixtures/update/drupal-8.site-branding-into-block-2005546.php
new file mode 100644
index 0000000..576762d
--- /dev/null
+++ b/core/modules/system/tests/fixtures/update/drupal-8.site-branding-into-block-2005546.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * @file
+ * Contains database additions to drupal-8.bare.standard.php.gz for testing the
+ * upgrade path of https://www.drupal.org/node/2005546.
+ */
+
+use Drupal\Core\Database\Database;
+
+$connection = Database::getConnection();
+
+// Structure of a custom block with visibility settings.
+$block_configs[] = \Drupal\Component\Serialization\Yaml::decode(file_get_contents(__DIR__ . '/block.block.testfor2005546.yml'));
+
+foreach ($block_configs as $block_config) {
+  $connection->insert('config')
+    ->fields([
+      'collection',
+      'name',
+      'data',
+    ])
+    ->values([
+      'collection' => '',
+      'name' => 'block.block.' . $block_config['id'],
+      'data' => serialize($block_config),
+    ])
+    ->execute();
+}
+
+// Update the config entity query "index".
+$existing_blocks = $connection->select('key_value')
+  ->fields('key_value', ['value'])
+  ->condition('collection', 'config.entity.key_store.block')
+  ->condition('name', 'theme:bartik')
+  ->execute()
+  ->fetchField();
+$existing_blocks = unserialize($existing_blocks);
+
+$connection->update('key_value')
+  ->fields([
+    'value' => serialize(array_merge($existing_blocks, ['block.block.bartik_branding']))
+  ])
+  ->condition('collection', 'config.entity.key_store.block')
+  ->condition('name', 'theme:bartik')
+  ->execute();
+
+// Enable test theme.
+$extensions = $connection->select('config')
+  ->fields('config', ['data'])
+  ->condition('name', 'core.extension')
+  ->execute()
+  ->fetchField();
+$extensions = unserialize($extensions);
+$connection->update('config')
+  ->fields([
+    'data' => serialize(array_merge_recursive($extensions, ['theme' => ['test_theme' => 0]]))
+  ])
+  ->condition('name', 'core.extension')
+  ->execute();