diff --git a/core/modules/aggregator/src/Plugin/FetcherInterface.php b/core/modules/aggregator/src/Plugin/FetcherInterface.php
index be9734e..9d08a3a 100644
--- a/core/modules/aggregator/src/Plugin/FetcherInterface.php
+++ b/core/modules/aggregator/src/Plugin/FetcherInterface.php
@@ -34,7 +34,7 @@
    *   Download the data at the URL and expose it
    *   to other modules by attaching it to $feed->source_string.
    *
-   * @return
+   * @return bool
    *   TRUE if fetching was successful, FALSE otherwise.
    */
   public function fetch(FeedInterface $feed);
diff --git a/core/modules/aggregator/src/Plugin/QueueWorker/AggregatorRefresh.php b/core/modules/aggregator/src/Plugin/QueueWorker/AggregatorRefresh.php
index d3267eb..5ec1f83 100644
--- a/core/modules/aggregator/src/Plugin/QueueWorker/AggregatorRefresh.php
+++ b/core/modules/aggregator/src/Plugin/QueueWorker/AggregatorRefresh.php
@@ -11,6 +11,8 @@
 use Drupal\Core\Queue\QueueWorkerBase;
 
 /**
+ * Ensures the feed is updated.
+ *
  * @QueueWorker(
  *   id = "aggregator_feeds",
  *   title = @Translation("Aggregator refresh"),
diff --git a/core/modules/aggregator/src/Plugin/aggregator/fetcher/DefaultFetcher.php b/core/modules/aggregator/src/Plugin/aggregator/fetcher/DefaultFetcher.php
index a3bdce0..be12c43 100644
--- a/core/modules/aggregator/src/Plugin/aggregator/fetcher/DefaultFetcher.php
+++ b/core/modules/aggregator/src/Plugin/aggregator/fetcher/DefaultFetcher.php
@@ -96,7 +96,6 @@ public function fetch(FeedInterface $feed) {
       $feed->http_headers = $response->getHeaders();
 
       // Update the feed URL in case of a 301 redirect.
-
       if ($response->getEffectiveUrl() != $feed->getUrl()) {
         $feed->setUrl($response->getEffectiveUrl());
       }
diff --git a/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php b/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
index cadd84b..800b5b0 100644
--- a/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
+++ b/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
@@ -192,8 +192,8 @@ public function process(FeedInterface $feed) {
     }
     foreach ($feed->items as $item) {
       // @todo: The default entity view builder always returns an empty
-      //   array, which is ignored in aggregator_save_item() currently. Should
-      //   probably be fixed.
+      // array, which is ignored in aggregator_save_item() currently. Should
+      // probably be fixed.
       if (empty($item['title'])) {
         continue;
       }
diff --git a/core/modules/aggregator/src/Plugin/views/field/TitleLink.php b/core/modules/aggregator/src/Plugin/views/field/TitleLink.php
index fa56ab2..ba05199 100644
--- a/core/modules/aggregator/src/Plugin/views/field/TitleLink.php
+++ b/core/modules/aggregator/src/Plugin/views/field/TitleLink.php
@@ -15,8 +15,9 @@
 use Drupal\views\ViewExecutable;
 
 /**
- * Defines a field handler that turns an item's title into a clickable link to
- * the original source article.
+ * Defines a field handler that turns an item's title into a clickable link.
+ *
+ * The link refers to the original source article.
  *
  * @ingroup views_field_handlers
  *
diff --git a/core/modules/aggregator/src/Tests/AggregatorTestBase.php b/core/modules/aggregator/src/Tests/AggregatorTestBase.php
index c0630ce..3c5a452 100644
--- a/core/modules/aggregator/src/Tests/AggregatorTestBase.php
+++ b/core/modules/aggregator/src/Tests/AggregatorTestBase.php
@@ -30,6 +30,9 @@
    */
   public static $modules = array('node', 'aggregator', 'aggregator_test', 'views');
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
 
@@ -237,7 +240,7 @@ public function uniqueFeed($feed_name, $feed_url) {
    * @return string
    *   Path to valid OPML file.
    */
-  public function getValidOpml($feeds) {
+  public function getValidOpml(array $feeds) {
     // Properly escape URLs so that XML parsers don't choke on them.
     foreach ($feeds as &$feed) {
       $feed['url[0][value]'] = htmlspecialchars($feed['url[0][value]']);
@@ -309,16 +312,34 @@ public function getEmptyOpml() {
     return file_unmanaged_save_data($opml, $path);
   }
 
+  /**
+   * Returns a example RSS091 feed.
+   *
+   * @return string
+   *   Path to the feed.
+   */
   public function getRSS091Sample() {
     return $GLOBALS['base_url'] . '/' . drupal_get_path('module', 'aggregator') . '/tests/modules/aggregator_test/aggregator_test_rss091.xml';
   }
 
+  /**
+   * Returns a example Atom feed.
+   *
+   * @return string
+   *   Path to the feed.
+   */
   public function getAtomSample() {
     // The content of this sample ATOM feed is based directly off of the
     // example provided in RFC 4287.
     return $GLOBALS['base_url'] . '/' . drupal_get_path('module', 'aggregator') . '/tests/modules/aggregator_test/aggregator_test_atom.xml';
   }
 
+  /**
+   * Returns a example feed.
+   *
+   * @return string
+   *   Path to the feed.
+   */
   public function getHtmlEntitiesSample() {
     return $GLOBALS['base_url'] . '/' . drupal_get_path('module', 'aggregator') . '/tests/modules/aggregator_test/aggregator_test_title_entities.xml';
   }
@@ -348,7 +369,7 @@ public function enableTestPlugins() {
       ->set('parser', 'aggregator_test_parser')
       ->set('processors', array(
         'aggregator_test_processor' => 'aggregator_test_processor',
-        'aggregator' => 'aggregator'
+        'aggregator' => 'aggregator',
       ))
       ->save();
   }
diff --git a/core/modules/aggregator/src/Tests/FeedFetcherPluginTest.php b/core/modules/aggregator/src/Tests/FeedFetcherPluginTest.php
index d98f0c7..618104f 100644
--- a/core/modules/aggregator/src/Tests/FeedFetcherPluginTest.php
+++ b/core/modules/aggregator/src/Tests/FeedFetcherPluginTest.php
@@ -16,6 +16,9 @@
  */
 class FeedFetcherPluginTest extends AggregatorTestBase {
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
     // Enable test plugins.
diff --git a/core/modules/aggregator/src/Tests/FeedLanguageTest.php b/core/modules/aggregator/src/Tests/FeedLanguageTest.php
index 1f48bb1..d259c82 100644
--- a/core/modules/aggregator/src/Tests/FeedLanguageTest.php
+++ b/core/modules/aggregator/src/Tests/FeedLanguageTest.php
@@ -30,6 +30,9 @@ class FeedLanguageTest extends AggregatorTestBase {
    */
   protected $langcodes = array();
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
 
diff --git a/core/modules/aggregator/src/Tests/FeedParserTest.php b/core/modules/aggregator/src/Tests/FeedParserTest.php
index 2e79ef3..371b10f 100644
--- a/core/modules/aggregator/src/Tests/FeedParserTest.php
+++ b/core/modules/aggregator/src/Tests/FeedParserTest.php
@@ -16,6 +16,10 @@
  * @group aggregator
  */
 class FeedParserTest extends AggregatorTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
     // Do not delete old aggregator items during these tests, since our sample
diff --git a/core/modules/aggregator/src/Tests/UpdateFeedItemTest.php b/core/modules/aggregator/src/Tests/UpdateFeedItemTest.php
index 046fd70..e100d64 100644
--- a/core/modules/aggregator/src/Tests/UpdateFeedItemTest.php
+++ b/core/modules/aggregator/src/Tests/UpdateFeedItemTest.php
@@ -17,7 +17,7 @@ class UpdateFeedItemTest extends AggregatorTestBase {
   /**
    * Tests running "update items" from 'admin/config/services/aggregator' page.
    */
-  function testUpdateFeedItem() {
+  public function testUpdateFeedItem() {
     $this->createSampleNodes();
 
     // Create a feed and test updating feed items if possible.
diff --git a/core/modules/aggregator/src/Tests/UpdateFeedTest.php b/core/modules/aggregator/src/Tests/UpdateFeedTest.php
index 16d47d9..71ca7de 100644
--- a/core/modules/aggregator/src/Tests/UpdateFeedTest.php
+++ b/core/modules/aggregator/src/Tests/UpdateFeedTest.php
@@ -23,7 +23,8 @@ public function testUpdateFeed() {
 
       // Get new feed data array and modify newly created feed.
       $edit = $this->getFeedEditArray();
-      $edit['refresh'] = 1800; // Change refresh value.
+      // Change refresh value.
+      $edit['refresh'] = 1800;
       if (isset($feed->{$same_field}->value)) {
         $edit[$same_field] = $feed->{$same_field}->value;
       }
@@ -39,8 +40,10 @@ public function testUpdateFeed() {
       $this->assertResponse(200, 'Feed source exists.');
       $this->assertText($edit['title[0][value]'], 'Page title');
 
+      // Set correct title so deleteFeed() will work.
+      $feed->title = $edit['title[0][value]'];
+
       // Delete feed.
-      $feed->title = $edit['title[0][value]']; // Set correct title so deleteFeed() will work.
       $this->deleteFeed($feed);
     }
   }