diff --git a/core/modules/aggregator/aggregator.admin.inc b/core/modules/aggregator/aggregator.admin.inc
index a859e85..eb55b95 100644
--- a/core/modules/aggregator/aggregator.admin.inc
+++ b/core/modules/aggregator/aggregator.admin.inc
@@ -2,14 +2,17 @@
 
 /**
  * @file
- * Admin page callbacks for the aggregator module.
+ * Administration page callbacks for the Aggregator module.
  */
 
 use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
 use Drupal\aggregator\Plugin\FetcherManager;
 
 /**
- * Page callback: Displays the aggregator administration page.
+ * Page callback: Displays the Aggregator administration page.
+ *
+ * @return string
+ *   A HTML-formatted string with administration page content.
  *
  * @see aggregator_menu()
  */
@@ -18,7 +21,7 @@ function aggregator_admin_overview() {
 }
 
 /**
- * Displays the aggregator administration page.
+ * Displays the Aggregator administration page.
  *
  * @return
  *   The page HTML.
@@ -92,8 +95,8 @@ function aggregator_view() {
  * Form constructor for adding and editing feed sources.
  *
  * @param $feed
- *   If editing a feed, the feed to edit as a PHP stdClass value; if adding a
- *   new feed, NULL.
+ *   (optional) If editing a feed, the feed to edit as a PHP stdClass value; if
+ *   adding a new feed, NULL. Defaults to NULL.
  *
  * @ingroup forms
  * @see aggregator_menu()
@@ -199,6 +202,7 @@ function aggregator_form_feed_validate($form, &$form_state) {
  * Form submission handler for aggregator_form_feed().
  *
  * @see aggregator_form_feed_validate()
+ *
  * @todo Add delete confirmation dialog.
  */
 function aggregator_form_feed_submit($form, &$form_state) {
@@ -453,7 +457,7 @@ function aggregator_admin_refresh_feed($feed) {
 }
 
 /**
- * Form constructor for the aggregator system settings.
+ * Form constructor for the Aggregator system settings.
  *
  * @see aggregator_menu()
  * @see aggregator_admin_form_submit()
@@ -578,7 +582,7 @@ function aggregator_admin_form_submit($form, &$form_state) {
 }
 
 /**
- * Form constructor to add/edit/delete aggregator categories.
+ * Form constructor to add/edit/delete Aggregator categories.
  *
  * @param $edit
  *   An associative array containing:
@@ -636,6 +640,7 @@ function aggregator_form_category_validate($form, &$form_state) {
  * Form submission handler for aggregator_form_category().
  *
  * @see aggregator_form_category_validate()
+ *
  * @todo Add delete confirmation dialog.
  */
 function aggregator_form_category_submit($form, &$form_state) {
diff --git a/core/modules/aggregator/aggregator.api.php b/core/modules/aggregator/aggregator.api.php
index a6cb1c5..632b3af 100644
--- a/core/modules/aggregator/aggregator.api.php
+++ b/core/modules/aggregator/aggregator.api.php
@@ -73,8 +73,8 @@ function hook_aggregator_fetch_info() {
  * @return
  *   TRUE if parsing was successful, FALSE otherwise.
  *
- * @see hook_aggregator_parse_info()
  * @see hook_aggregator_fetch()
+ * @see hook_aggregator_parse_info()
  * @see hook_aggregator_process()
  *
  * @ingroup aggregator
@@ -131,9 +131,9 @@ function hook_aggregator_parse_info() {
  *   $feed->items array. For the exact format refer to the particular parser in
  *   use.
  *
- * @see hook_aggregator_process_info()
  * @see hook_aggregator_fetch()
  * @see hook_aggregator_parse()
+ * @see hook_aggregator_process_info()
  *
  * @ingroup aggregator
  */
diff --git a/core/modules/aggregator/aggregator.install b/core/modules/aggregator/aggregator.install
index bc0a369..c02c0b7 100644
--- a/core/modules/aggregator/aggregator.install
+++ b/core/modules/aggregator/aggregator.install
@@ -259,7 +259,7 @@ function aggregator_schema() {
 }
 
 /**
- * Moves aggregator settings from variables to config.
+ * Move Aggregator settings from variables to config.
  *
  * @ingroup config_upgrade
  */
diff --git a/core/modules/aggregator/aggregator.module b/core/modules/aggregator/aggregator.module
index 047026a..5f13c80 100644
--- a/core/modules/aggregator/aggregator.module
+++ b/core/modules/aggregator/aggregator.module
@@ -267,20 +267,20 @@ function aggregator_menu() {
 }
 
 /**
- * Title callback: Returns a title for aggregatory category pages.
+ * Title callback: Returns a title for Aggregator category pages.
  *
  * @param $category
- *   An aggregator category.
+ *   An Aggregator category.
  *
  * @return
- *   An aggregator category title.
+ *   A string with the Aggregator category title.
  */
 function _aggregator_category_title($category) {
   return $category['title'];
 }
 
 /**
- * Access callback: Determines whether there are any aggregator categories.
+ * Access callback: Determines whether there are any Aggregator categories.
  *
  * @return
  *   TRUE if there is at least one category and the user has access to them;
@@ -436,7 +436,7 @@ function aggregator_block_view($delta = '') {
 }
 
 /**
- * Adds/edits/deletes aggregator categories.
+ * Adds/edits/deletes Aggregator categories.
  *
  * @param $edit
  *   An associative array describing the category to be added/edited/deleted.
@@ -487,7 +487,7 @@ function aggregator_save_category($edit) {
 }
 
 /**
- * Adds/edits/deletes an aggregator feed.
+ * Adds/edits/deletes an Aggregator feed.
  *
  * @param $edit
  *   An associative array describing the feed to be added/edited/deleted.
@@ -688,7 +688,7 @@ function aggregator_refresh($feed) {
 }
 
 /**
- * Loads an aggregator feed.
+ * Loads an Aggregator feed.
  *
  * @param $fid
  *   The feed id.
@@ -706,7 +706,7 @@ function aggregator_feed_load($fid) {
 }
 
 /**
- * Loads an aggregator category.
+ * Loads an Aggregator category.
  *
  * @param $cid
  *   The category id.
@@ -739,7 +739,7 @@ function theme_aggregator_block_item($variables) {
 }
 
 /**
- * Safely renders HTML content, as allowed.
+ * Renders the HTML content safely, as allowed.
  *
  * @param $value
  *   The content to be filtered.
@@ -752,10 +752,10 @@ function aggregator_filter_xss($value) {
 }
 
 /**
- * Checks and sanitizes the aggregator configuration.
+ * Checks and sanitizes the Aggregator configuration.
  *
  * Goes through all fetchers, parsers and processors and checks whether they
- * are available. If one is missing resets to standard configuration.
+ * are available. If one is missing, resets to standard configuration.
  *
  * @return
  *   TRUE if this function resets the configuration; FALSE if not.
@@ -794,7 +794,7 @@ function aggregator_sanitize_configuration() {
  *   Items count.
  *
  * @return
- *   Plural-formatted "@count items"
+ *   A string that is plural-formatted as "@count items"
  */
 function _aggregator_items($count) {
   return format_plural($count, '1 item', '@count items');
diff --git a/core/modules/aggregator/aggregator.pages.inc b/core/modules/aggregator/aggregator.pages.inc
index 78ca5bc..a06ad2e 100644
--- a/core/modules/aggregator/aggregator.pages.inc
+++ b/core/modules/aggregator/aggregator.pages.inc
@@ -2,12 +2,15 @@
 
 /**
  * @file
- * User page callbacks for the aggregator module.
+ * User page callbacks for the Aggregator module.
  */
 
 /**
  * Page callback: Displays the most recent items gathered from any feed.
  *
+ * @return string
+ *   The rendered list of items for the feed.
+ *
  * @see aggregator_menu()
  */
 function aggregator_page_last() {
@@ -19,11 +22,14 @@ function aggregator_page_last() {
 }
 
 /**
- * Page callback: Displays all the items captured from a particular feed.
+ * Page callback: Displays all the items captured from the particular feed.
  *
  * @param $feed
  *   The feed for which to display all items.
  *
+ * @return string
+ *   The rendered list of items for the feed.
+ *
  * @see aggregator_menu()
  */
 function aggregator_page_source($feed) {
@@ -41,7 +47,10 @@ function aggregator_page_source($feed) {
  * Form constructor to show all items captured from a feed.
  *
  * @param $feed
- *   The feed for which to list all the aggregated items.
+ *   The feed for which to list all of the aggregated items.
+ *
+ * @return string
+ *   The rendered list of items for the feed.
  *
  * @see aggregator_menu()
  * @see aggregator_page_source()
@@ -55,7 +64,10 @@ function aggregator_page_source_form($form, $form_state, $feed) {
  * Form constructor to list items aggregated in a category.
  *
  * @param $category
- *   The category for which to list all the aggregated items.
+ *   The category for which to list all of the aggregated items.
+ *
+ * @return string
+ *   The rendered list of items for the feed.
  *
  * @see aggregator_menu()
  * @ingroup forms
@@ -74,7 +86,10 @@ function aggregator_page_category($category) {
  * Form constructor to list items aggregated in a category.
  *
  * @param $category
- *   The category for which to list all the aggregated items.
+ *   The category for which to list all of the aggregated items.
+ *
+ * @return string
+ *   The rendered list of items for the feed.
  *
  * @see aggregator_menu()
  * @see aggregator_page_category()
@@ -162,7 +177,7 @@ function aggregator_load_feed_items($type, $data = NULL) {
  *   The feed source URL.
  *
  * @return
- *   The rendered list of items for a feed.
+ *   The rendered list of items for the feed.
  */
 function _aggregator_page_list($items, $op, $feed_source = '') {
   if (user_access('administer news feeds') && ($op == 'categorize')) {
@@ -184,13 +199,17 @@ function _aggregator_page_list($items, $op, $feed_source = '') {
 /**
  * Form constructor to build the page list form.
  *
- * @param $items
+ * @param array $items
  *   An array of the feed items.
- * @param $feed_source
- *   The feed source URL.
+ * @param string $feed_source
+ *   (optional) The feed source URL. Defaults to an empty string.
+ *
+ * @return array
+ *   An array of FAPI elements.
  *
- * @ingroup forms
  * @see aggregator_categorize_items_submit()
+ * @see theme_aggregator_categorize_items()
+ * @ingroup forms
  */
 function aggregator_categorize_items($items, $feed_source = '') {
   $form['#submit'][] = 'aggregator_categorize_items_submit';
@@ -345,7 +364,10 @@ function template_preprocess_aggregator_item(&$variables) {
 }
 
 /**
- * Page callback: Displays all the feeds used by the aggregator.
+ * Page callback: Displays all the feeds used by the Aggregator module.
+ *
+ * @return string
+ *   An HTML-formatted string.
  *
  * @see aggregator_menu()
  */
@@ -372,7 +394,10 @@ function aggregator_page_sources() {
 }
 
 /**
- * Page callback: Displays all the categories used by the aggregator.
+ * Page callback: Displays all the categories used by the Aggregator module.
+ *
+ * @return string
+ *   An HTML formatted string.
  *
  * @see aggregator_menu()
  */
@@ -399,6 +424,9 @@ function aggregator_page_categories() {
 /**
  * Page callback: Generates an RSS 0.92 feed of aggregator items or categories.
  *
+ * @return string
+ *   An HTML formatted string.
+ *
  * @see aggregator_menu()
  */
 function aggregator_page_rss() {
@@ -420,15 +448,13 @@ function aggregator_page_rss() {
 }
 
 /**
- * Prints the RSS page for a feed.
+ * Prints the RSS page for the feed.
  *
  * @param $variables
  *   An associative array containing:
  *   - feeds: An array of the feeds to theme.
  *   - category: A common category, if any, for all the feeds.
  *
- * @return void
- *
  * @ingroup themeable
  */
 function theme_aggregator_page_rss($variables) {
@@ -471,8 +497,11 @@ function theme_aggregator_page_rss($variables) {
  * Page callback: Generates an OPML representation of all feeds.
  *
  * @param $cid
- *   If set, feeds are exported only from a category with this ID. Otherwise,
- *   all feeds are exported.
+ *   (optional) If set, feeds are exported only from a category with this ID.
+ *   Otherwise, all feeds are exported. Defaults to NULL.
+ *
+ * @return string
+ *   An HTML formatted string.
  *
  * @see aggregator_menu()
  */
@@ -489,14 +518,12 @@ function aggregator_page_opml($cid = NULL) {
 }
 
 /**
- * Prints the OPML page for a feed.
+ * Prints the OPML page for the feed.
  *
- * @param $variables
+ * @param array $variables
  *   An associative array containing:
  *   - feeds: An array of the feeds to theme.
  *
- * @return void
- *
  * @ingroup themeable
  */
 function theme_aggregator_page_opml($variables) {
diff --git a/core/modules/aggregator/aggregator.processor.inc b/core/modules/aggregator/aggregator.processor.inc
index b333a96..d3f272a 100644
--- a/core/modules/aggregator/aggregator.processor.inc
+++ b/core/modules/aggregator/aggregator.processor.inc
@@ -133,6 +133,12 @@ function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
  *
  * Callback for drupal_map_assoc() within
  * aggregator_form_aggregator_admin_form_alter().
+ *
+ * @param int $length
+ *   The desired length of teaser text, in bytes.
+ *
+ * @return string
+ *   A translated string explaining the teaser string length.
  */
 function _aggregator_characters($length) {
   return ($length == 0) ? t('Unlimited') : format_plural($length, '1 character', '@count characters');
diff --git a/core/modules/aggregator/aggregator.theme-rtl.css b/core/modules/aggregator/aggregator.theme-rtl.css
index f02ae91..3efccd0 100644
--- a/core/modules/aggregator/aggregator.theme-rtl.css
+++ b/core/modules/aggregator/aggregator.theme-rtl.css
@@ -1,3 +1,7 @@
+/**
+ * Right-to-Left styles for theme in Aggregator module.
+ */
+
 .aggregator .feed-icon {
   float: left;
 }
diff --git a/core/modules/aggregator/aggregator.theme.css b/core/modules/aggregator/aggregator.theme.css
index e2182ac..7943913 100644
--- a/core/modules/aggregator/aggregator.theme.css
+++ b/core/modules/aggregator/aggregator.theme.css
@@ -1,3 +1,7 @@
+/**
+ * Styles for theme in Aggregator module.
+ */
+
 .aggregator .feed-icon {
   float: right; /* LTR */
   display: block;
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/FetcherInterface.php b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/FetcherInterface.php
index 39fc19d..6c79a59 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Plugin/FetcherInterface.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Plugin/FetcherInterface.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file
  * Definition of Drupal\aggregator\Plugin\FetcherInterface.
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AddFeedTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AddFeedTest.php
index 69ad6d6..2e66ca9 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AddFeedTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AddFeedTest.php
@@ -8,7 +8,7 @@
 namespace Drupal\aggregator\Tests;
 
 /**
- * Tests aggregator feed adding.
+ * Tests Aggregator feed adding.
  */
 class AddFeedTest extends AggregatorTestBase {
   public static function getInfo() {
@@ -20,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Create a feed, ensure that it is unique, check the source, and delete the feed.
+   * Creates and ensures that a feed is unique, checks source, and deletes feed.
    */
   function testAddFeed() {
     $feed = $this->createFeed();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorConfigurationTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorConfigurationTest.php
index 503b9a1..2c5fccb 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorConfigurationTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorConfigurationTest.php
@@ -8,7 +8,7 @@
 namespace Drupal\aggregator\Tests;
 
 /**
- * Tests aggregator configuration settings.
+ * Tests the configuration settings functionality in the Aggregator module.
  */
 class AggregatorConfigurationTest extends AggregatorTestBase {
   public static function getInfo() {
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorCronTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorCronTest.php
index 0966937..1154be5 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorCronTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorCronTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests cron process functionality in Aggregator module.
+ */
 class AggregatorCronTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Add feeds update them on cron.
+   * Adds feeds and updates them via cron process.
    */
   public function testCron() {
     // Create feed and test basic updating on cron.
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
index 7f09317..3955014 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorRenderingTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests rendering functionality in Aggregator module.
+ */
 class AggregatorRenderingTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,9 +20,9 @@ public static function getInfo() {
   }
 
   /**
-   * Add a feed block to the page and checks its links.
+   * Adds a feed block to the page and checks its links.
    *
-   * TODO: Test the category block as well.
+   * @todo Test the category block as well.
    */
   public function testBlockLinks() {
     // Create feed.
@@ -78,7 +81,7 @@ public function testBlockLinks() {
   }
 
   /**
-   * Create a feed and check that feed's page.
+   * Creates a feed and checks that feed's page.
    */
   public function testFeedPage() {
     // Increase the number of items published in the rss.xml feed so we have
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorTestBase.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorTestBase.php
index f46c2c4..3ff2ac6 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorTestBase.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/AggregatorTestBase.php
@@ -10,7 +10,7 @@
 use Drupal\simpletest\WebTestBase;
 
 /**
- * Defines a base class for testing aggregator.module.
+ * Defines a base class for testing the Aggregator module.
  */
 abstract class AggregatorTestBase extends WebTestBase {
 
@@ -34,10 +34,15 @@ function setUp() {
   }
 
   /**
-   * Create an aggregator feed (simulate form submission on admin/config/services/aggregator/add/feed).
+   * Creates an Aggregator feed.
+   *
+   * This method simulates the form submission on path
+   * admin/config/services/aggregator/add/feed.
    *
    * @param $feed_url
-   *   If given, feed will be created with this URL, otherwise /rss.xml will be used.
+   *   (optional) If given, feed will be created with this URL, otherwise
+   *   /rss.xml will be used. Defaults to NULL.
+   *
    * @return $feed
    *   Full feed object if possible.
    *
@@ -54,7 +59,7 @@ function createFeed($feed_url = NULL) {
   }
 
   /**
-   * Delete an aggregator feed.
+   * Deletes an Aggregator feed.
    *
    * @param $feed
    *   Feed object representing the feed.
@@ -65,10 +70,12 @@ function deleteFeed($feed) {
   }
 
   /**
-   * Return a randomly generated feed edit array.
+   * Returns a randomly generated feed edit array.
    *
    * @param $feed_url
-   *   If given, feed will be created with this URL, otherwise /rss.xml will be used.
+   *   (optional) If given, feed will be created with this URL, otherwise
+   *   /rss.xml will be used. Defaults to NULL.
+   *
    * @return
    *   A feed array.
    */
@@ -89,7 +96,7 @@ function getFeedEditArray($feed_url = NULL) {
   }
 
   /**
-   * Return the count of the randomly created feed array.
+   * Returns the count of the randomly created feed array.
    *
    * @return
    *   Number of feed items on default feed created by createFeed().
@@ -101,10 +108,13 @@ function getDefaultFeedItemCount() {
   }
 
   /**
-   * Update feed items (simulate click to admin/config/services/aggregator/update/$fid).
+   * Updates the feed items.
+   *
+   * This method simulates a click to
+   * admin/config/services/aggregator/update/$fid.
    *
    * @param $feed
-   *   Feed object representing the feed.
+   *   Feed object representing the feed, passed by reference.
    * @param $expected_count
    *   Expected number of feed items.
    */
@@ -133,7 +143,7 @@ function updateFeedItems(&$feed, $expected_count) {
   }
 
   /**
-   * Confirm item removal from a feed.
+   * Confirms an item removal from a feed.
    *
    * @param $feed
    *   Feed object representing the feed.
@@ -144,7 +154,7 @@ function removeFeedItems($feed) {
   }
 
   /**
-   * Add and remove feed items and ensure that the count is zero.
+   * Adds and removes feed items and ensure that the count is zero.
    *
    * @param $feed
    *   Feed object representing the feed.
@@ -161,7 +171,7 @@ function updateAndRemove($feed, $expected_count) {
   }
 
   /**
-   * Pull feed categories from aggregator_category_feed table.
+   * Pulls feed categories from {aggregator_category_feed} table.
    *
    * @param $feed
    *   Feed object representing the feed.
@@ -175,7 +185,11 @@ function getFeedCategories($feed) {
   }
 
   /**
-   * Pull categories from aggregator_category table.
+   * Pulls categories from {aggregator_category} table.
+   *
+   * @return array
+   *   An associative array keyed by category ID and values are set to the
+   *   category names.
    */
   function getCategories() {
     $categories = array();
@@ -186,14 +200,14 @@ function getCategories() {
     return $categories;
   }
 
-
   /**
-   * Check if the feed name and url is unique.
+   * Checks if the feed name and url is unique.
    *
    * @param $feed_name
    *   String containing the feed name to check.
    * @param $feed_url
    *   String containing the feed url to check.
+   *
    * @return
    *   TRUE if feed is unique.
    */
@@ -203,10 +217,11 @@ function uniqueFeed($feed_name, $feed_url) {
   }
 
   /**
-   * Create a valid OPML file from an array of feeds.
+   * Creates a valid OPML file from an array of feeds.
    *
    * @param $feeds
    *   An array of feeds.
+   *
    * @return
    *   Path to valid OPML file.
    */
@@ -244,7 +259,7 @@ function getValidOpml($feeds) {
   }
 
   /**
-   * Create an invalid OPML file.
+   * Creates an invalid OPML file.
    *
    * @return
    *   Path to invalid OPML file.
@@ -261,7 +276,7 @@ function getInvalidOpml() {
   }
 
   /**
-   * Create a valid but empty OPML file.
+   * Creates a valid but empty OPML file.
    *
    * @return
    *   Path to empty OPML file.
@@ -300,7 +315,7 @@ function getHtmlEntitiesSample() {
    * Creates sample article nodes.
    *
    * @param $count
-   *   (optional) The number of nodes to generate.
+   *   (optional) The number of nodes to generate. Defaults to five.
    */
   function createSampleNodes($count = 5) {
     $langcode = LANGUAGE_NOT_SPECIFIED;
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedItemTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedItemTest.php
index ae71799..5aa5808 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedItemTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedItemTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests categorization functionality in Aggregator module.
+ */
 class CategorizeFeedItemTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,6 +20,8 @@ public static function getInfo() {
   }
 
   /**
+   * Checks that children of a feed inherit a defined category.
+   *
    * If a feed has a category, make sure that the children inherit that
    * categorization.
    */
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
index 977dbcb..dab885d 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/CategorizeFeedTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests the categorize feed functionality in Aggregator module.
+ */
 class CategorizeFeedTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Create a feed and make sure you can add more than one category to it.
+   * Creates a feed and makes sure you can add more than one category to it.
    */
   function testCategorizeFeed() {
 
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
index 907bc3a..5cc0415 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/FeedParserTest.php
@@ -8,7 +8,7 @@
 namespace Drupal\aggregator\Tests;
 
 /**
- * Tests for feed parsing.
+ * Tests for feed parsing in the Aggregator module.
  */
 class FeedParserTest extends AggregatorTestBase {
   public static function getInfo() {
@@ -28,7 +28,7 @@ function setUp() {
   }
 
   /**
-   * Test a feed that uses the RSS 0.91 format.
+   * Tests a feed that uses the RSS 0.91 format.
    */
   function testRSS091Sample() {
     $feed = $this->createFeed($this->getRSS091Sample());
@@ -50,7 +50,7 @@ function testRSS091Sample() {
   }
 
   /**
-   * Test a feed that uses the Atom format.
+   * Tests a feed that uses the Atom format.
    */
   function testAtomSample() {
     $feed = $this->createFeed($this->getAtomSample());
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/ImportOpmlTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/ImportOpmlTest.php
index 0e2f1e9..273c8b1 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/ImportOpmlTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/ImportOpmlTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests importing feeds from OPML functionality for Aggregator module.
+ */
 class ImportOpmlTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Open OPML import form.
+   * Opens OPML import form.
    */
   function openImportForm() {
     db_delete('aggregator_category')->execute();
@@ -39,7 +42,7 @@ function openImportForm() {
   }
 
   /**
-   * Submit form filled with invalid fields.
+   * Submits form filled with invalid fields.
    */
   function validateImportFormFields() {
     $before = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
@@ -65,7 +68,7 @@ function validateImportFormFields() {
   }
 
   /**
-   * Submit form with invalid, empty and valid OPML files.
+   * Submits form with invalid, empty and valid OPML files.
    */
   function submitImportForm() {
     $before = db_query('SELECT COUNT(*) FROM {aggregator_feed}')->fetchField();
@@ -124,6 +127,9 @@ function submitImportForm() {
     $this->assertTrue($category, 'Categories are correct.');
   }
 
+  /**
+   * Tests the import of an OPML feed.
+   */
   function testOpmlImport() {
     $this->openImportForm();
     $this->validateImportFormFields();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedItemTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedItemTest.php
index 32433ae..1e9de6f 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedItemTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedItemTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests removing a feed item functionality in the Aggregator module.
+ */
 class RemoveFeedItemTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Test running "remove items" from the 'admin/config/services/aggregator' page.
+   * Tests running "remove items" from 'admin/config/services/aggregator' page.
    */
   function testRemoveFeedItem() {
     // Create a bunch of test feeds.
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedTest.php
index 983ec57..e756193 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/RemoveFeedTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Test the removal of a feed functionality in the Aggregator module.
+ */
 class RemoveFeedTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Remove a feed and ensure that all it services are removed.
+   * Removes a feed and ensures that all of its services are removed.
    */
   function testRemoveFeed() {
     $feed = $this->createFeed();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedItemTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedItemTest.php
index bf1d2be..f94001e 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedItemTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedItemTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests updating a feed item functionality in the Aggregator module.
+ */
 class UpdateFeedItemTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Test running "update items" from the 'admin/config/services/aggregator' page.
+   * Tests running "update items" from 'admin/config/services/aggregator' page.
    */
   function testUpdateFeedItem() {
     $this->createSampleNodes();
diff --git a/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedTest.php b/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedTest.php
index fd8a828..b976436 100644
--- a/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedTest.php
+++ b/core/modules/aggregator/lib/Drupal/aggregator/Tests/UpdateFeedTest.php
@@ -7,6 +7,9 @@
 
 namespace Drupal\aggregator\Tests;
 
+/**
+ * Tests updating the feed functionality in the Aggregator module.
+ */
 class UpdateFeedTest extends AggregatorTestBase {
   public static function getInfo() {
     return array(
@@ -17,7 +20,7 @@ public static function getInfo() {
   }
 
   /**
-   * Create a feed and attempt to update it.
+   * Creates a feed and attempts to update it.
    */
   function testUpdateFeed() {
     $remamining_fields = array('title', 'url', '');